RE: AC Power Primer?
jrbar...@lexmark.com wrote: > > An aspect that I just heard of yesterday, from one of our Product Safety > engineers, is that Australia, Argentina, and the People's > Republic of China have > what looks like the identical plug. The Australian plug is used > over much of > the South Pacific. The prongs for the Chinese plug are 1mm > longer than the > prongs in the Australian plug. The prongs in the Argentina plug > are 1mm longer > that the prongs in the Australian plug, AND hot and neutral are swapped! < nod > One of the reasons why I was asking my question. If an 'international' version of a power supply has trouble with a reversed input, then there'd definitely be a problem in Germany. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
Andrew Carson" wrote: > With phase connected to the phase terminal and neutral connected to the > neutral terminal, the international version was fine on the immunities. It > was only when the PSU was connected to a phase to phase supply, or the > phase and neutral reversed, that the problem became apparent. An example > of, despite outward appearances, not all supplies can be reliably > connected to phase to phase or any input terminal to phase and the other > to neutral. An aspect that I just heard of yesterday, from one of our Product Safety engineers, is that Australia, Argentina, and the People's Republic of China have what looks like the identical plug. The Australian plug is used over much of the South Pacific. The prongs for the Chinese plug are 1mm longer than the prongs in the Australian plug. The prongs in the Argentina plug are 1mm longer that the prongs in the Australian plug, AND hot and neutral are swapped! John Barnes Advisory Engineer Lexmark International --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
With phase connected to the phase terminal and neutral connected to the neutral terminal, the international version was fine on the immunities. It was only when the PSU was connected to a phase to phase supply, or the phase and neutral reversed, that the problem became apparent. An example of, despite outward appearances, not all supplies can be reliably connected to phase to phase or any input terminal to phase and the other to neutral. Doug McKean wrote: > "Andrew Carson" wrote: > > > > I encountered a problem with power supply a few years back. It would > haply > > run across a wide range of input voltages, phase to neutral or phase > ot > > phase, it did not really care. Apart from one little capacitor > sitting in > > the EMF noise filter. It was polarized and only happy if the Phase > and > > neutral were the correct way around. The effect of reversing the > polarity > > was harmonic distortions with measured current harmonics upto the > 39th > > order. Also the immunity to the line noise changed, changing form > happily > > shaking of a 3kV surge, to watching the boost caps explode at a 2kV > surge. > > Would run with either terminal connected to the phase, but a whole > new emc > > profile. The standard offering had this capacitor, the USA version > did > > not. Only difference on the power supply, two letters in a 20 > character > > part number. These little things do sometimes catch designers by > surprise. > > I'm not quite sure I understand. The US version had to be used to > pass > immunity testing when the international version couldn't pass > immunity? > > - Doug McKean > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson:pstc_ad...@garretson.org > Dave Healddavehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > http://www.rcic.com/ click on "Virtual Conference Hall," -- Andrew Carson - Product Safety Engineer Xyratex Engineering Laboratory Tele 023 92496855 Fax 023 92496014 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
"Andrew Carson" wrote: > > I encountered a problem with power supply a few years back. It would haply > run across a wide range of input voltages, phase to neutral or phase ot > phase, it did not really care. Apart from one little capacitor sitting in > the EMF noise filter. It was polarized and only happy if the Phase and > neutral were the correct way around. The effect of reversing the polarity > was harmonic distortions with measured current harmonics upto the 39th > order. Also the immunity to the line noise changed, changing form happily > shaking of a 3kV surge, to watching the boost caps explode at a 2kV surge. > Would run with either terminal connected to the phase, but a whole new emc > profile. The standard offering had this capacitor, the USA version did > not. Only difference on the power supply, two letters in a 20 character > part number. These little things do sometimes catch designers by surprise. I'm not quite sure I understand. The US version had to be used to pass immunity testing when the international version couldn't pass immunity? - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
I encountered a problem with power supply a few years back. It would haply run across a wide range of input voltages, phase to neutral or phase ot phase, it did not really care. Apart from one little capacitor sitting in the EMF noise filter. It was polarized and only happy if the Phase and neutral were the correct way around. The effect of reversing the polarity was harmonic distortions with measured current harmonics upto the 39th order. Also the immunity to the line noise changed, changing form happily shaking of a 3kV surge, to watching the boost caps explode at a 2kV surge. Would run with either terminal connected to the phase, but a whole new emc profile. The standard offering had this capacitor, the USA version did not. Only difference on the power supply, two letters in a 20 character part number. These little things do sometimes catch designers by surprise. Doug McKean wrote: > From: > > > > Another potential problem I see with calling both a phase-to-phase > > connection and a phase-to-neutral connection, "single-phase" is that > it > > presumes that all power supplies can be connected either way. What > if a > > vendor designs a system in which the power supply is changed many > times over > > the years? Can you be absolutely, 100% sure that any power supply > that you, > > or your successor, select will work with a phase-to-phase > connection? Would > > you bet your reputation on it? Would you bet your job on it? > > Uh, yes - I have many times and do with the products I've > worked on. That's part of my job responsibility. > > My original statement which may have been lost in translation > was the following - *IF* you can connect either as input, you > have a single phase system, AFAIC. > > Your examples are obviously valid if those are the issues at > hand. But, they are outside my point and do not contradict > what I originally said. If however these issues are surprises > in the course of someone's job, then of course there's > reason for concern. > > Regards, Doug McKean > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson:pstc_ad...@garretson.org > Dave Healddavehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > http://www.rcic.com/ click on "Virtual Conference Hall," -- Andrew Carson - Product Safety Engineer Xyratex Engineering Laboratory Tele 023 92496855 Fax 023 92496014 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
Palomar observatory will look forward to these blackouts (they have generators). And my (battery-operated) scope will be ready. Always a good side to others' misfortunes ... -Original Message- From: Peter Tarver [mailto:peter.tar...@sanmina.com] Sent: Monday, May 07, 2001 11:04 AM To: emc-p...@ieee.org Subject: RE: AC Power Primer? Not so. Most household appliances contain motors (excluding entertainment appliances). Motors (ac induction types; the most commonly used) are generally less efficient at lower voltages (largely by virtue of their increased I^2*R loss) and draw more current to perform the same amount of work or produce the same amount of torque. Thus, more load on the grid. Imagine all the air conditioners and fan motors laboring under a voltage depression this summer. California would be dark a lot quicker --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
Not so. Most household appliances contain motors (excluding entertainment appliances). Motors (ac induction types; the most commonly used) are generally less efficient at lower voltages (largely by virtue of their increased I^2*R loss) and draw more current to perform the same amount of work or produce the same amount of torque. Thus, more load on the grid. Imagine all the air conditioners and fan motors laboring under a voltage depression this summer. California would be dark a lot quicker. Regards, Peter L. Tarver peter.tar...@sanmina.com > -Original Message- > From: owner-emc-p...@ieee.org > [mailto:owner-emc-p...@ieee.org]On Behalf > Of Hans Mellberg > Sent: Friday, May 04, 2001 9:05 AM > To: Nerad, Daren HS-SNS; 'Price, Ed'; 'mkel...@es.com'; > emc-p...@ieee.org > Subject: RE: AC Power Primer? > > > > Daren, you bring up an interesting point. > California's energy woes could possibly be > band-aid if the voltage was reduced 10%. (maybe > that is too big of a management > issue, does anyone know?) Assuming that a large > percentage of the users don't have > switcher regulators then that would equate to a > 5-9% reduction in energy consumption > hence reducing California's power problems > significantly till more power plants are > built. That might lower the spot market price! > > --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
One of the formulas for power is Voltage Squared/Resistance. So, in the case where the load is purely resistive (and doesn't change), a dramatic reduction in power can be obtained by reducing the voltage. Max Kelson Evans & Sutherland -Original Message- From: Ravinder Ajmani [mailto:ajm...@us.ibm.com] Sent: Friday, May 04, 2001 11:28 AM To: emc-p...@ieee.org Subject: RE: AC Power Primer? Can someone explain to me how reducing the voltage will lower the power consumption, if the load is kept constant. On the contrary, this should cause an increase in consumption because higher current means increased copper losses in the wiring. This is the reason why power distribution is done at very high voltage levels. Regards, Ravinder PCB Development and Design Department IBM Corporation Email: ajm...@us.ibm.com *** Always do right. This will gratify some people and astonish the rest. . Mark Twain Hans Mellberg @ieee.org on 05/04/2001 09:04:41 AM Please respond to Hans Mellberg Sent by: owner-emc-p...@ieee.org To: "Nerad, DarenHS-SNS" , "'Price, Ed'" , "'mkel...@es.com'" , emc-p...@ieee.org cc: Subject: RE: AC Power Primer? Daren, you bring up an interesting point. California's energy woes could possibly be band-aid if the voltage was reduced 10%. (maybe that is too big of a management issue, does anyone know?) Assuming that a large percentage of the users don't have switcher regulators then that would equate to a 5-9% reduction in energy consumption hence reducing California's power problems significantly till more power plants are built. That might lower the spot market price! --- "Nerad, DarenHS-SNS" wrote: > > It all boils down to $$$s! > Notice you don't see 110 V on the lines, probably not even 115 or 117 but as > close to 120V as they can keep it (except for you folks in CA, then this is > a digital thing, HA!). > > WHY? > > You consume more Watts if the V is greater! > > Check your wall outlet, what does it read? > > IT would be interesting to use this forum to do a quick & dirty survey. > Granted we can only hit where engineers feel like making measurements, & > when they do, but it would be interesting... > > Daren A. Nerad > EMC Engineer > = Best Regards Hans Mellberg Regulatory Compliance Consultant and Design Services By the Pacific Coast next to Silicon Valley Santa Cruz, CA, USA 408-507-9694 __ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
<236f133b43f4d211a4b00090273c79dc060b6...@us-rv-exch-2.rsvl.unisys.com>, Richardson, William G wrote: >The important thing to note is that a good amount of the utility load is not >constant power. It is light bulbs, toasters, coffeemakers, hairdryers and >electric heaters and so on. So lowering the voltage 10 % is the first step - >the so-called brown-outs. Power is a square function, so the new power is >then 90% times 90% or only 81% of the original load. Not with light bulbs, actually. At a lower voltage the filament temperature is lower, so the resistance is lower. Over a certain voltage range, a lamp draws a nearly constant current, so for a 10% voltage drop, the power drops by around 10%. not 20%. -- Regards, John Woodgate, OOO - Own Opinions Only. Phone +44 (0)1268 747839 Fax +44 (0)1268 777124. http://www.jmwa.demon.co.uk Why not call a vertically- applied manulo-pedally-operated quasi-planar chernozem-penetrating and excavating implement a SPADE? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
, Ravinder Ajmani wrote: >Can someone explain to me how reducing the voltage will lower the power >consumption, if the load is kept constant. What is it about the load that you propose is kept constant? If the load is a constant resistance R, Ohm's and Joule's Laws give you W = V^2/R, so reducing the voltage V reduces the power W. You are probably thinking in terms of switch-mode power supplies, where the input current increases if the input voltage decreases. The incremental input resistance is thus negative, but you can't put such an incremental value into W =V^2/R. For these power supplies, W is approximately constant, and independent of V, within the specified range of input voltage. -- Regards, John Woodgate, OOO - Own Opinions Only. Phone +44 (0)1268 747839 Fax +44 (0)1268 777124. http://www.jmwa.demon.co.uk Why not call a vertically- applied manulo-pedally-operated quasi-planar chernozem-penetrating and excavating implement a SPADE? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
From: > > Another potential problem I see with calling both a phase-to-phase > connection and a phase-to-neutral connection, "single-phase" is that it > presumes that all power supplies can be connected either way. What if a > vendor designs a system in which the power supply is changed many times over > the years? Can you be absolutely, 100% sure that any power supply that you, > or your successor, select will work with a phase-to-phase connection? Would > you bet your reputation on it? Would you bet your job on it? Uh, yes - I have many times and do with the products I've worked on. That's part of my job responsibility. My original statement which may have been lost in translation was the following - *IF* you can connect either as input, you have a single phase system, AFAIC. Your examples are obviously valid if those are the issues at hand. But, they are outside my point and do not contradict what I originally said. If however these issues are surprises in the course of someone's job, then of course there's reason for concern. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
Rick, and group members, I thought that I would weigh in with an opinion on this one. The definition of phase should be determined by the requirements of the equipment. If the equipment only requires single phase power, regardless of voltage, then that is what should be specified. It does not matter if this single phase is derived from a three phase source, it is still single phase. One way to determine this is to ask yourself if the equipment could be powered from a single phase electronic ac source. In my experience true two phase equipment is extremely rare. Instead, what we usually find are racks of equipment intended to be supplied from split phase (such as the typical U.S. residential service). This is because the rack either contains a mix of 120V and 240V equipment, or the 120V equipment draws too much current for a single circuit and must be split into two groups. None of these setups actually require two phases of the same source and could easily be rewired to operate from completely separate circuits. If anyone is still confused, here is some (greatly simplified) background on electrical power generation. Single phase alternators (often mistakenly called generators) produce a single sinusoidal cycle for each revolution of the input shaft. Frequency is determined by rotational speed. If an additional connection is made at the midpoint of the winding the alternator becomes a split phase type such as the 120V/240V types commonly sold as portable power sources. Three phase alternators have additional windings that each produce a single sinusoidal cycle for every revolution of the input shaft. These waveforms are staggered in time so that the peaks do not coincide with each other. This is the most efficient way to generate electrical power. This is why power companies use them. Automobile alternators are also three phase. The outputs are rectified by diode pairs to produce a pulsating dc output. The battery acts as a filter. If an oscilloscope lead is placed right at the alternator terminals a slight trace of the waveform can be seen. It is possible to detect "blown" diodes that way. Scott Lacey -Original Message- From: owner-emc-p...@ieee.org [mailto:owner-emc-p...@ieee.org]On Behalf Of rbus...@es.com Sent: Wednesday, May 02, 2001 4:31 PM To: emc-p...@majordomo.ieee.org Subject: AC Power Primer? I am in the process of assisting our publications group with documenting an ac power configuration. As simple as this sounds, it turns out there are varying opinions in our engineering group regarding the naming convention for input power, in particular single phase verses two phase. We all probably agree that a phase to neutral connection is single phase and devices that use all thee phases, whether they are 208V 60Hz or 400V 50Hz, are truly three phase. The discussion heats up when you are talking about a phase to phase connection on a three phase distribution (208 or 400V). Is this called single phase or two phase? It has been suggested that in the European community it is called two phase, while in the U.S. we call it single phase. I am looking for opinions or discussion on this issue. On a related note in the U.S. we have 240V 60Hz (two 120V drops) coming into our into our homes. This is provided by a transformer with a center taped winding. On the outside legs of the transformer we have 240V but between either outside leg and neutral (center tap) we have 120V. I would call this a single phase system with two additive (in phase) 120V windings. Again others have called this two phase. My apologies to the group if this is a stupid question. Its just one of those nagging questions. Rick Busche Evans & Sutherland Salt Lake City, Utah rbus...@es.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions,
RE: AC Power Primer?
The important thing to note is that a good amount of the utility load is not constant power. It is light bulbs, toasters, coffeemakers, hairdryers and electric heaters and so on. So lowering the voltage 10 % is the first step - the so-called brown-outs. Power is a square function, so the new power is then 90% times 90% or only 81% of the original load. Bill Richardson -Original Message- From: Ravinder Ajmani [mailto:ajm...@us.ibm.com] Sent: Friday, May 04, 2001 12:28 PM To: emc-p...@ieee.org Subject: RE: AC Power Primer? Can someone explain to me how reducing the voltage will lower the power consumption, if the load is kept constant. On the contrary, this should cause an increase in consumption because higher current means increased copper losses in the wiring. This is the reason why power distribution is done at very high voltage levels. Regards, Ravinder PCB Development and Design Department IBM Corporation Email: ajm...@us.ibm.com *** Always do right. This will gratify some people and astonish the rest. . Mark Twain Hans Mellberg @ieee.org on 05/04/2001 09:04:41 AM Please respond to Hans Mellberg Sent by: owner-emc-p...@ieee.org To: "Nerad, DarenHS-SNS" , "'Price, Ed'" , "'mkel...@es.com'" , emc-p...@ieee.org cc: Subject: RE: AC Power Primer? Daren, you bring up an interesting point. California's energy woes could possibly be band-aid if the voltage was reduced 10%. (maybe that is too big of a management issue, does anyone know?) Assuming that a large percentage of the users don't have switcher regulators then that would equate to a 5-9% reduction in energy consumption hence reducing California's power problems significantly till more power plants are built. That might lower the spot market price! --- "Nerad, DarenHS-SNS" wrote: > > It all boils down to $$$s! > Notice you don't see 110 V on the lines, probably not even 115 or 117 but as > close to 120V as they can keep it (except for you folks in CA, then this is > a digital thing, HA!). > > WHY? > > You consume more Watts if the V is greater! > > Check your wall outlet, what does it read? > > IT would be interesting to use this forum to do a quick & dirty survey. > Granted we can only hit where engineers feel like making measurements, & > when they do, but it would be interesting... > > Daren A. Nerad > EMC Engineer > = Best Regards Hans Mellberg Regulatory Compliance Consultant and Design Services By the Pacific Coast next to Silicon Valley Santa Cruz, CA, USA 408-507-9694 __ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee
RE: AC Power Primer?
It looks like California does run on reduced voltage. See the following URL, for instance: <http://www.world.std.com/~techbook/seec2_2.htm> http://www.world.std.com/~techbook/seec2_2.htm It says: 2.2.2 North America ANSI C84.1 "Electric Power Systems and Equipment - Voltage Ratings (60 Hz) sets the preferred nominal voltage at 120V and allows a range of 114 - 126V (240V nominal, range 228 - 252V). Equivalent Canadian spec is CAN3-C235. Voltage at a 120 volt nominal single phase receptacle should be 110 to 125V under normal conditions. However, the California Public Utilities Commission has specified that the service voltage shall be kept in the range 114-120V, with some exceptions. This was done because some studies showed a reduction in energy consumption at the lower voltages. Max Kelson, Evans & Sutherland --- To: "Nerad, DarenHS-SNS" , "'Price, Ed'" , "'mkel...@es.com'" , emc-p...@ieee.org cc: Subject: RE: AC Power Primer? Daren, you bring up an interesting point. California's energy woes could possibly be band-aid if the voltage was reduced 10%. (maybe that is too big of a management issue, does anyone know?) Assuming that a large percentage of the users don't have switcher regulators then that would equate to a 5-9% reduction in energy consumption hence reducing California's power problems significantly till more power plants are built. That might lower the spot market price! --- "Nerad, DarenHS-SNS" wrote: > > It all boils down to $$$s! > Notice you don't see 110 V on the lines, probably not even 115 or 117 but as > close to 120V as they can keep it (except for you folks in CA, then this is > a digital thing, HA!). > > WHY? > > You consume more Watts if the V is greater! > > Check your wall outlet, what does it read? > > IT would be interesting to use this forum to do a quick & dirty survey. > Granted we can only hit where engineers feel like making measurements, & > when they do, but it would be interesting... > > Daren A. Nerad > EMC Engineer > = Best Regards Hans Mellberg Regulatory Compliance Consultant and Design Services By the Pacific Coast next to Silicon Valley Santa Cruz, CA, USA 408-507-9694 __ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices <http://auctions.yahoo.com/> http://auctions.yahoo.com/ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: <http://www.ewh.ieee.org/soc/emcs/pstc/> http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: <http://www.rcic.com/> http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: <http://www.ewh.ieee.org/soc/emcs/pstc/> http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: <http://www.rcic.com/> http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
Can someone explain to me how reducing the voltage will lower the power consumption, if the load is kept constant. On the contrary, this should cause an increase in consumption because higher current means increased copper losses in the wiring. This is the reason why power distribution is done at very high voltage levels. Regards, Ravinder PCB Development and Design Department IBM Corporation Email: ajm...@us.ibm.com *** Always do right. This will gratify some people and astonish the rest. . Mark Twain Hans Mellberg @ieee.org on 05/04/2001 09:04:41 AM Please respond to Hans Mellberg Sent by: owner-emc-p...@ieee.org To: "Nerad, DarenHS-SNS" , "'Price, Ed'" , "'mkel...@es.com'" , emc-p...@ieee.org cc: Subject: RE: AC Power Primer? Daren, you bring up an interesting point. California's energy woes could possibly be band-aid if the voltage was reduced 10%. (maybe that is too big of a management issue, does anyone know?) Assuming that a large percentage of the users don't have switcher regulators then that would equate to a 5-9% reduction in energy consumption hence reducing California's power problems significantly till more power plants are built. That might lower the spot market price! --- "Nerad, DarenHS-SNS" wrote: > > It all boils down to $$$s! > Notice you don't see 110 V on the lines, probably not even 115 or 117 but as > close to 120V as they can keep it (except for you folks in CA, then this is > a digital thing, HA!). > > WHY? > > You consume more Watts if the V is greater! > > Check your wall outlet, what does it read? > > IT would be interesting to use this forum to do a quick & dirty survey. > Granted we can only hit where engineers feel like making measurements, & > when they do, but it would be interesting... > > Daren A. Nerad > EMC Engineer > = Best Regards Hans Mellberg Regulatory Compliance Consultant and Design Services By the Pacific Coast next to Silicon Valley Santa Cruz, CA, USA 408-507-9694 __ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
Daren, you bring up an interesting point. California's energy woes could possibly be band-aid if the voltage was reduced 10%. (maybe that is too big of a management issue, does anyone know?) Assuming that a large percentage of the users don't have switcher regulators then that would equate to a 5-9% reduction in energy consumption hence reducing California's power problems significantly till more power plants are built. That might lower the spot market price! --- "Nerad, DarenHS-SNS" wrote: > > It all boils down to $$$s! > Notice you don't see 110 V on the lines, probably not even 115 or 117 but as > close to 120V as they can keep it (except for you folks in CA, then this is > a digital thing, HA!). > > WHY? > > You consume more Watts if the V is greater! > > Check your wall outlet, what does it read? > > IT would be interesting to use this forum to do a quick & dirty survey. > Granted we can only hit where engineers feel like making measurements, & > when they do, but it would be interesting... > > Daren A. Nerad > EMC Engineer > = Best Regards Hans Mellberg Regulatory Compliance Consultant and Design Services By the Pacific Coast next to Silicon Valley Santa Cruz, CA, USA 408-507-9694 __ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
The US 220 came from the days of single phase split winding transformers yielding 110 to Neutral. Not a three phase thing but, the "open-delta" two phase transformers used in residential distribution, were two split winding transformers wound is a three phase style with the third winding missing. It also provided splits for 110V and are truly a two phase system. But a matter of semantics. The open delta transformer was a cost reduced virtual three phase!!!. --- mkel...@es.com wrote: > > Just out of curiosity, where does the designation "220V come from? If you > measure the potential difference between two phases of a three-phase system, > you get 208V. If you measure the difference between the two phases in a > residential or light commercial area, you would probably get 240V. > > So, where does the term "220V" come from? > > Thanks, > > Max Kelson > Evans & Sutherland = Best Regards Hans Mellberg Regulatory Compliance Consultant and Design Services By the Pacific Coast next to Silicon Valley Santa Cruz, CA, USA 408-507-9694 __ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
>From the point of view of an electrician or a technician, I can understand, to some extent, how one could consider a phase-to-phase connection as being single phase. From the point of view of a design engineer, however, there would probably be some differences. With a system that references neutral you might only use one circuit breaker for instance and one of the wires connected to the power supply would be blue. There is also a potential problem in providing documentation for customers. If a vendor's documentation specifies a single-phase connection and indicates that the power supply is auto-ranging, a European customer would assume that the product was plug and play compatible with European line voltage. When he plugged it in, however, the supply would fry with 400V, phase-to-phase voltage across the inputs. You could solve this problem, I suppose, by sending the European customer a "true" single-phase system and sending the American customer a "pseudo?" single-phase system. For U.S. customers, you need to add a voltage specification to try to help the him understand the requirements since some customers might expect that the term single phase means a phase to neutral connection. Many (most?) manufacturer's might say "220 VAC, single-phase" to clarify things. Now the plot thickens even more since there is no such thing as "220 VAC" in the U.S., unless the customer has some unusual facilities wiring. Standard, nominal voltages in the US for light-industrial installations are 208 and 120. At this point, I wouldn't be surprised if the vendor were to get a call from a customer asking: "Hey do you guys really know what you're doing?". Another potential problem I see with calling both a phase-to-phase connection and a phase-to-neutral connection, "single-phase" is that it presumes that all power supplies can be connected either way. What if a vendor designs a system in which the power supply is changed many times over the years? Can you be absolutely, 100% sure that any power supply that you, or your successor, select will work with a phase-to-phase connection? Would you bet your reputation on it? Would you bet your job on it? What if the guy that designed the power supply happened to hang a relatively low-voltage capacitor from the neutral input to ground, for instance? It's possible, I suppose, that a technician or electrician might be able to use the same term to describe two different configurations. A design engineer cannot. Max Kelson Evans & Sutherland -Original Message- From: Doug McKean [mailto:dmck...@corp.auspex.com] Sent: Thursday, May 03, 2001 7:30 PM To: emc-p...@majordomo.ieee.org Subject: Re: AC Power Primer? In my experience, a system that gets its power from a power supply which for input has either a transformer or a switcher with a two port input across which is connected one hot line and one neutral line or two hots out of phase from each other, that system is a 'single phase' system. Even though two phases may be used as power input, the effectivity is to act as a single phase input and can operate that way as well. In other words, if you can plug and chug with no problems by replacing an input consisting of two hots out of phase from each other by a single phase hot/neutral input, then you've got a single phase system. It's effectively what the primary 'sees', one phase and that's what's counts, AFAIC. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
, Price, Ed wrote: >The nominal 208 Vrms value exists >from any phase-to-phase pair. The voltage from any phase to neutral is 115 >Vrms. 208/sqrt(3) = 120, not 115. 110 V was around in the 1920s, AIUI. By WW2, the voltage had already crept up to 115 V or thereabouts, witness the tubes like 117N7GT, with 117 V heaters. -- Regards, John Woodgate, OOO - Own Opinions Only. Phone +44 (0)1268 747839 Fax +44 (0)1268 777124. http://www.jmwa.demon.co.uk Why not call a vertically- applied manulo-pedally-operated quasi-planar chernozem-penetrating and excavating implement a SPADE? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
Hi Brian. << Just to add a little more fuel to the flames! We supplied an Instrument to a well known semiconductor Manufacturer in Oregon which was powered from two 220 volt phases. I marked the rating plate as 220 volt one phase as has been suggested. However the local inspector made us change it to 220 volt two phase. So what is the correct definition. >> I was always encouraged to describe a supply by how many phases were not earthed, and a device by how many phases it used. In that context there is no such thing as a two phase device, at least not in the UK, as a two phase device would have three wires and the third phase is already there as the algebraic sum of the two phases. In the UK the distribution system is Earthed Neutral 3 phase equal star. In the USA and many other places there are all sorts of systems, e.g. open delta - earthed centre tap one phase, close delta earthed on phase, two phase earthed centre tap... the list is long.. In the UK, we use 1 phase and neutral, or three phases with or without neutral. Industrial systems use 2 phases, usually for control transformers which are single phase devices running at 415V, as there is no neutral. In the UK neutral and Earth are tied together at the distribution room, but NO current is permitted in the local Protective Earth conductor or the 30mA RCD's trip. I think your local inspector was probably OK in asking for the label to say Two Phase, as it was a Single phase device connected to Two phases. Sound reasonable? Chris Dupres Surrey, UK. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
In my experience, a system that gets its power from a power supply which for input has either a transformer or a switcher with a two port input across which is connected one hot line and one neutral line or two hots out of phase from each other, that system is a 'single phase' system. Even though two phases may be used as power input, the effectivity is to act as a single phase input and can operate that way as well. In other words, if you can plug and chug with no problems by replacing an input consisting of two hots out of phase from each other by a single phase hot/neutral input, then you've got a single phase system. It's effectively what the primary 'sees', one phase and that's what's counts, AFAIC. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
All right... I had heard this from a former nuclear power plant worker (NOT Homer Simpson, opposite end of intelligence spectrum). Passed it on as a bit of cynical (realist?) humor... (the caffeine in the Mountain Dew made me get an early jump on "Friday Funnies") Daren A. Nerad EMC Engineer 815.226.6123 -Original Message- From: mkel...@es.com [mailto:mkel...@es.com] Sent: Thursday, May 03, 2001 4:57 PM To: emc-p...@ieee.org Subject: RE: AC Power Primer? Look at the bright side. With a higher voltage, your wife can buy more kitchen appliances and put more of them on the same circuit :) -Original Message- From: Nerad, Daren HS-SNS [mailto:daren.ne...@hs.utc.com] Sent: Thursday, May 03, 2001 2:32 PM To: 'Price, Ed'; 'mkel...@es.com'; emc-p...@ieee.org Subject: RE: AC Power Primer? It all boils down to $$$s! Notice you don't see 110 V on the lines, probably not even 115 or 117 but as close to 120V as they can keep it (except for you folks in CA, then this is a digital thing, HA!). WHY? You consume more Watts if the V is greater! Check your wall outlet, what does it read? IT would be interesting to use this forum to do a quick & dirty survey. Granted we can only hit where engineers feel like making measurements, & when they do, but it would be interesting... Daren A. Nerad EMC Engineer -Original Message- From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: Thursday, May 03, 2001 1:05 PM To: 'mkel...@es.com'; emc-p...@ieee.org Subject: RE: AC Power Primer? >-Original Message- >From: mkel...@es.com [mailto:mkel...@es.com] >Sent: Thursday, May 03, 2001 8:22 AM >To: brian.harl...@vgscientific.com; emc-p...@ieee.org >Subject: RE: AC Power Primer? > > > >Just out of curiosity, where does the designation "220V come >from? If you >measure the potential difference between two phases of a >three-phase system, >you get 208V. If you measure the difference between the two >phases in a >residential or light commercial area, you would probably get 240V. > >So, where does the term "220V" come from? > >Thanks, > >Max Kelson >Evans & Sutherland > [SNIP] Max: There's many more expert than I on this subject, but The USA has several "standard" powers available to non-heavy industrial consumers. A typical home is supplied with a three-wire drop (although the trend is not to drop, but to bury the feeders) that consists of two hot wires and a return. The return line is grounded. The voltage from hot to hot is 240 Vrms, and is a single phase. The transformer that supplies the several homes on the last power branch has a center-tapped secondary, so the voltage from either hot to the center-tap is 120 Vrms. I have heard the hot-to-center-tap voltage called 110 V, 115 V, 117 V and 120 V. That would mean the hot-to-hot voltage would be either 220 V, 230 V 234 V or 240 V. FWIW, the voltage at my home (between blackouts, I live in Southern California) consistently runs about 119 Vrms. High-power appliances (air conditioning, range, heating) are usually designed to draw from the hot-to-hot 240 Vrms (this minimizes losses). Lesser loads are connected from one hot to the neutral, hopefully with some thought toward balancing the total load. Light industrial users are often fed by a five-wire three-phase wye system (three phases, neutral and safety ground). The nominal 208 Vrms value exists from any phase-to-phase pair. The voltage from any phase to neutral is 115 Vrms. Heavy loads (large motors) are usually 3-phase models, and other heavy loads (like industrial ovens) also draw phase-to-phase power. The phase-to-neutral voltage is close enough to residential values that ordinary lights, appliances and computers can be fed from this circuit. Again, you should try to balance the phase-to-neutral loads. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --
RE: AC Power Primer?
Look at the bright side. With a higher voltage, your wife can buy more kitchen appliances and put more of them on the same circuit :) -Original Message- From: Nerad, Daren HS-SNS [mailto:daren.ne...@hs.utc.com] Sent: Thursday, May 03, 2001 2:32 PM To: 'Price, Ed'; 'mkel...@es.com'; emc-p...@ieee.org Subject: RE: AC Power Primer? It all boils down to $$$s! Notice you don't see 110 V on the lines, probably not even 115 or 117 but as close to 120V as they can keep it (except for you folks in CA, then this is a digital thing, HA!). WHY? You consume more Watts if the V is greater! Check your wall outlet, what does it read? IT would be interesting to use this forum to do a quick & dirty survey. Granted we can only hit where engineers feel like making measurements, & when they do, but it would be interesting... Daren A. Nerad EMC Engineer -Original Message- From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: Thursday, May 03, 2001 1:05 PM To: 'mkel...@es.com'; emc-p...@ieee.org Subject: RE: AC Power Primer? >-Original Message- >From: mkel...@es.com [mailto:mkel...@es.com] >Sent: Thursday, May 03, 2001 8:22 AM >To: brian.harl...@vgscientific.com; emc-p...@ieee.org >Subject: RE: AC Power Primer? > > > >Just out of curiosity, where does the designation "220V come >from? If you >measure the potential difference between two phases of a >three-phase system, >you get 208V. If you measure the difference between the two >phases in a >residential or light commercial area, you would probably get 240V. > >So, where does the term "220V" come from? > >Thanks, > >Max Kelson >Evans & Sutherland > [SNIP] Max: There's many more expert than I on this subject, but The USA has several "standard" powers available to non-heavy industrial consumers. A typical home is supplied with a three-wire drop (although the trend is not to drop, but to bury the feeders) that consists of two hot wires and a return. The return line is grounded. The voltage from hot to hot is 240 Vrms, and is a single phase. The transformer that supplies the several homes on the last power branch has a center-tapped secondary, so the voltage from either hot to the center-tap is 120 Vrms. I have heard the hot-to-center-tap voltage called 110 V, 115 V, 117 V and 120 V. That would mean the hot-to-hot voltage would be either 220 V, 230 V 234 V or 240 V. FWIW, the voltage at my home (between blackouts, I live in Southern California) consistently runs about 119 Vrms. High-power appliances (air conditioning, range, heating) are usually designed to draw from the hot-to-hot 240 Vrms (this minimizes losses). Lesser loads are connected from one hot to the neutral, hopefully with some thought toward balancing the total load. Light industrial users are often fed by a five-wire three-phase wye system (three phases, neutral and safety ground). The nominal 208 Vrms value exists from any phase-to-phase pair. The voltage from any phase to neutral is 115 Vrms. Heavy loads (large motors) are usually 3-phase models, and other heavy loads (like industrial ovens) also draw phase-to-phase power. The phase-to-neutral voltage is close enough to residential values that ordinary lights, appliances and computers can be fed from this circuit. Again, you should try to balance the phase-to-neutral loads. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For po
RE: AC Power Primer?
>-Original Message- >From: Nerad, Daren HS-SNS [mailto:daren.ne...@hs.utc.com] >Sent: Thursday, May 03, 2001 1:32 PM >To: Price, Ed; 'mkel...@es.com'; emc-p...@ieee.org >Subject: RE: AC Power Primer? > > >It all boils down to $$$s! >Notice you don't see 110 V on the lines, probably not even 115 >or 117 but as >close to 120V as they can keep it (except for you folks in CA, >then this is >a digital thing, HA!). > >WHY? > >You consume more Watts if the V is greater! > >Check your wall outlet, what does it read? > >IT would be interesting to use this forum to do a quick & dirty survey. >Granted we can only hit where engineers feel like making >measurements, & >when they do, but it would be interesting... > >Daren A. Nerad >EMC Engineer > [SNIP] Daren: That's true for only a small amount of your total residential load. In most cases, I'm happy to be on the high end of the voltage tolerance. My electric saw cuts better, my hedge trimmers let me move a bit faster, and the air conditioning fan moves more air. My big electric loads (refrigerator & air conditioning) may draw more Watts when they run, but they move the heat faster, and thus shut off sooner. It's not the Watts you pay for; it's the Watt-hours. There's good consulting money for those who can predict the optimum voltage versus run-time to minimize total cost. The higher voltage may cause the incandescent lights to put out a bit more light than you expect, and the lights will fail sooner. But most of my lights are either fluorescent or have dimmers, so I can set the amount of light I want. Ahh, the weekend draws near, and I can instead contemplate the economy. My power company wants to add a surcharge due to the rising cost of gasoline. The gasoline station is adding a surcharge due to the rapidly rising cost of electricity. The water company has already added a surcharge due to the increased cost of electricity and gasoline. My sewer fees are indexed to the cost of water. And the donut shop has stopped giving a baker's dozen. This must have been what life felt like when compound interest was discovered. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
It all boils down to $$$s! Notice you don't see 110 V on the lines, probably not even 115 or 117 but as close to 120V as they can keep it (except for you folks in CA, then this is a digital thing, HA!). WHY? You consume more Watts if the V is greater! Check your wall outlet, what does it read? IT would be interesting to use this forum to do a quick & dirty survey. Granted we can only hit where engineers feel like making measurements, & when they do, but it would be interesting... Daren A. Nerad EMC Engineer -Original Message- From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: Thursday, May 03, 2001 1:05 PM To: 'mkel...@es.com'; emc-p...@ieee.org Subject: RE: AC Power Primer? >-Original Message- >From: mkel...@es.com [mailto:mkel...@es.com] >Sent: Thursday, May 03, 2001 8:22 AM >To: brian.harl...@vgscientific.com; emc-p...@ieee.org >Subject: RE: AC Power Primer? > > > >Just out of curiosity, where does the designation "220V come >from? If you >measure the potential difference between two phases of a >three-phase system, >you get 208V. If you measure the difference between the two >phases in a >residential or light commercial area, you would probably get 240V. > >So, where does the term "220V" come from? > >Thanks, > >Max Kelson >Evans & Sutherland > [SNIP] Max: There's many more expert than I on this subject, but The USA has several "standard" powers available to non-heavy industrial consumers. A typical home is supplied with a three-wire drop (although the trend is not to drop, but to bury the feeders) that consists of two hot wires and a return. The return line is grounded. The voltage from hot to hot is 240 Vrms, and is a single phase. The transformer that supplies the several homes on the last power branch has a center-tapped secondary, so the voltage from either hot to the center-tap is 120 Vrms. I have heard the hot-to-center-tap voltage called 110 V, 115 V, 117 V and 120 V. That would mean the hot-to-hot voltage would be either 220 V, 230 V 234 V or 240 V. FWIW, the voltage at my home (between blackouts, I live in Southern California) consistently runs about 119 Vrms. High-power appliances (air conditioning, range, heating) are usually designed to draw from the hot-to-hot 240 Vrms (this minimizes losses). Lesser loads are connected from one hot to the neutral, hopefully with some thought toward balancing the total load. Light industrial users are often fed by a five-wire three-phase wye system (three phases, neutral and safety ground). The nominal 208 Vrms value exists from any phase-to-phase pair. The voltage from any phase to neutral is 115 Vrms. Heavy loads (large motors) are usually 3-phase models, and other heavy loads (like industrial ovens) also draw phase-to-phase power. The phase-to-neutral voltage is close enough to residential values that ordinary lights, appliances and computers can be fed from this circuit. Again, you should try to balance the phase-to-neutral loads. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
>-Original Message- >From: mkel...@es.com [mailto:mkel...@es.com] >Sent: Thursday, May 03, 2001 8:22 AM >To: brian.harl...@vgscientific.com; emc-p...@ieee.org >Subject: RE: AC Power Primer? > > > >Just out of curiosity, where does the designation "220V come >from? If you >measure the potential difference between two phases of a >three-phase system, >you get 208V. If you measure the difference between the two >phases in a >residential or light commercial area, you would probably get 240V. > >So, where does the term "220V" come from? > >Thanks, > >Max Kelson >Evans & Sutherland > [SNIP] Max: There's many more expert than I on this subject, but The USA has several "standard" powers available to non-heavy industrial consumers. A typical home is supplied with a three-wire drop (although the trend is not to drop, but to bury the feeders) that consists of two hot wires and a return. The return line is grounded. The voltage from hot to hot is 240 Vrms, and is a single phase. The transformer that supplies the several homes on the last power branch has a center-tapped secondary, so the voltage from either hot to the center-tap is 120 Vrms. I have heard the hot-to-center-tap voltage called 110 V, 115 V, 117 V and 120 V. That would mean the hot-to-hot voltage would be either 220 V, 230 V 234 V or 240 V. FWIW, the voltage at my home (between blackouts, I live in Southern California) consistently runs about 119 Vrms. High-power appliances (air conditioning, range, heating) are usually designed to draw from the hot-to-hot 240 Vrms (this minimizes losses). Lesser loads are connected from one hot to the neutral, hopefully with some thought toward balancing the total load. Light industrial users are often fed by a five-wire three-phase wye system (three phases, neutral and safety ground). The nominal 208 Vrms value exists from any phase-to-phase pair. The voltage from any phase to neutral is 115 Vrms. Heavy loads (large motors) are usually 3-phase models, and other heavy loads (like industrial ovens) also draw phase-to-phase power. The phase-to-neutral voltage is close enough to residential values that ordinary lights, appliances and computers can be fed from this circuit. Again, you should try to balance the phase-to-neutral loads. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
Just out of curiosity, where does the designation "220V come from? If you measure the potential difference between two phases of a three-phase system, you get 208V. If you measure the difference between the two phases in a residential or light commercial area, you would probably get 240V. So, where does the term "220V" come from? Thanks, Max Kelson Evans & Sutherland -Original Message- From: Brian Harlowe [mailto:brian.harl...@vgscientific.com] Sent: Thursday, May 03, 2001 1:48 AM To: 'emc-p...@ieee.org' Subject: RE: AC Power Primer? Hi everybody Just to add a little more fuel to the flames! We supplied an Instrument to a well known semiconductor Manufacturer in Oregon which was powered from two 220 volt phases. I marked the rating plate as 220 volt one phase as has been suggested. However the local inspector made us change it to 220 volt two phase. So what is the correct definition. Brian Harlowe Thermo V.G. Scientific Tel +44 (0)1342 327211 Fax +44 (0)1342 315074 > -Original Message- > From: rbus...@es.com > Sent: 02 May 2001 21:31 > To: emc-p...@majordomo.ieee.org > Subject: AC Power Primer? > > > I am in the process of assisting our publications group with documenting > an > ac power configuration. As simple as this sounds, it turns out there are > varying opinions in our engineering group regarding the naming convention > for input power, in particular single phase verses two phase. > > We all probably agree that a phase to neutral connection is single phase > and > devices that use all thee phases, whether they are 208V 60Hz or 400V 50Hz, > are truly three phase. The discussion heats up when you are talking about > a > phase to phase connection on a three phase distribution (208 or 400V). Is > this called single phase or two phase? It has been suggested that in the > European community it is called two phase, while in the U.S. we call it > single phase. I am looking for opinions or discussion on this issue. > > On a related note in the U.S. we have 240V 60Hz (two 120V drops) coming > into > our into our homes. This is provided by a transformer with a center taped > winding. On the outside legs of the transformer we have 240V but between > either outside leg and neutral (center tap) we have 120V. I would call > this > a single phase system with two additive (in phase) 120V windings. Again > others have called this two phase. > > My apologies to the group if this is a stupid question. Its just one of > those nagging questions. > > Rick Busche > Evans & Sutherland > Salt Lake City, Utah > > rbus...@es.com > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson:pstc_ad...@garretson.org > Dave Healddavehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
Re:Rick Busche's question. We all probably agree that a phase to neutral connection is single phase and devices that use all three phases, whether they are 208V 60Hz or 400V 50Hz, are truly three phase. The discussion heats up when you are talking about a phase to phase connection on a three phase distribution (208 or 400V). Is this called single phase or two phase? It has been suggested that in the European community it is called two phase, while in the U.S. we call it single phase. I am looking for opinions or discussion on this issue. Response: I don't know the official answer but as for the phase-to-phase, why not just call it that? Some one somewhere has to make names for the others, let's just decide right here and not to start calling the phase-to-phase system "phase-to-phase". That is the most descriptive and eliminates the single or two phase quandary. * * * * * * Re: Fred Townsend's hypothetical. "Think where we would be today if Edison had won. Response: Well, we wouldn't be talking about the number of phases. We would have developed something different with which to confuse people. Oscar No body, no where, no how, is responsible for any thing I say. Unless of course they like it and then they thought of it first. Therefore, this is yours to do with as you see fit. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
<3af0c662.79a83...@poasana.com>, Fred Townsend inimitably wrote: >Calling such a circuit "two phase" is somewhat dangerous in that there really >are 2 phase circuits (180 degree) But if you 'ground' your double-beam scope to the neutral, as usual, and look at the two live conductors, you see two waveforms, 180 degrees out of phase. What other sort of 'two-phase' circuit, with 180 degrees phase difference, can exist? > as well as 6 phase (65 degree) around! That I would very much like to see! Have you re-defined pi as 3.403392041...?(;-) -- Regards, John Woodgate, OOO - Own Opinions Only. Phone +44 (0)1268 747839 Fax +44 (0)1268 777124. http://www.jmwa.demon.co.uk Why not call a vertically- applied manulo-pedally-operated quasi-planar chernozem-penetrating and excavating implement a SPADE? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
<1d0833cb3b1d7244b617a0dc8399c27e01010...@vega.corp.es.com>, rbus...@es.com inimitably wrote: >The discussion heats up when you are talking about a >phase to phase connection on a three phase distribution (208 or 400V). Is >this called single phase or two phase? It has been suggested that in the >European community it is called two phase, while in the U.S. we call it >single phase. I am looking for opinions or discussion on this issue. In IEC SC77A, we have called this 'interphase' connection, which seems acceptable on both sides of the Atlantic. > >On a related note in the U.S. we have 240V 60Hz (two 120V drops) coming into >our into our homes. This is provided by a transformer with a center taped >winding. On the outside legs of the transformer we have 240V but between >either outside leg and neutral (center tap) we have 120V. I would call this >a single phase system with two additive (in phase) 120V windings. Again >others have called this two phase. Yes, US usage is to call this 'single phase', and it is a mug's game to try to alter usage. But logic indicates that it is a two-phase system, 0 and 180 degrees. Provided everyone understands that, there is no point in arguing about which is 'right'. > >My apologies to the group if this is a stupid question. Its just one of >those nagging questions. No, it's not stupid; the situation is confusing and needs to be aired. -- Regards, John Woodgate, OOO - Own Opinions Only. Phone +44 (0)1268 747839 Fax +44 (0)1268 777124. http://www.jmwa.demon.co.uk Why not call a vertically- applied manulo-pedally-operated quasi-planar chernozem-penetrating and excavating implement a SPADE? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
Hi everybody Just to add a little more fuel to the flames! We supplied an Instrument to a well known semiconductor Manufacturer in Oregon which was powered from two 220 volt phases. I marked the rating plate as 220 volt one phase as has been suggested. However the local inspector made us change it to 220 volt two phase. So what is the correct definition. Brian Harlowe Thermo V.G. Scientific Tel +44 (0)1342 327211 Fax +44 (0)1342 315074 > -Original Message- > From: rbus...@es.com > Sent: 02 May 2001 21:31 > To: emc-p...@majordomo.ieee.org > Subject: AC Power Primer? > > > I am in the process of assisting our publications group with documenting > an > ac power configuration. As simple as this sounds, it turns out there are > varying opinions in our engineering group regarding the naming convention > for input power, in particular single phase verses two phase. > > We all probably agree that a phase to neutral connection is single phase > and > devices that use all thee phases, whether they are 208V 60Hz or 400V 50Hz, > are truly three phase. The discussion heats up when you are talking about > a > phase to phase connection on a three phase distribution (208 or 400V). Is > this called single phase or two phase? It has been suggested that in the > European community it is called two phase, while in the U.S. we call it > single phase. I am looking for opinions or discussion on this issue. > > On a related note in the U.S. we have 240V 60Hz (two 120V drops) coming > into > our into our homes. This is provided by a transformer with a center taped > winding. On the outside legs of the transformer we have 240V but between > either outside leg and neutral (center tap) we have 120V. I would call > this > a single phase system with two additive (in phase) 120V windings. Again > others have called this two phase. > > My apologies to the group if this is a stupid question. Its just one of > those nagging questions. > > Rick Busche > Evans & Sutherland > Salt Lake City, Utah > > rbus...@es.com > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson:pstc_ad...@garretson.org > Dave Healddavehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: AC Power Primer?
I can't speak for the European community but in the US the circuit you describe is single phase. If I put a phase meter or scope on it I will not be able to measure a phase difference. I can buy split phase as Jim suggests . There are split phase motors that run from a single phase that use a capacitor to shift the phase. Calling such a circuit "two phase" is somewhat dangerous in that there really are 2 phase circuits (180 degree) as well as 6 phase (65 degree) around! I suspect most of these even phased circuits are relegated to museums by now since they are holdovers from the days when the "AC boys" battled Edison's "DC" at the turn of the century. Think where we would be today if Edison had won. Fred Townsend Silicon Valley rbus...@es.com wrote: > I am in the process of assisting our publications group with documenting an > ac power configuration. As simple as this sounds, it turns out there are > varying opinions in our engineering group regarding the naming convention > for input power, in particular single phase verses two phase. > > We all probably agree that a phase to neutral connection is single phase and > devices that use all thee phases, whether they are 208V 60Hz or 400V 50Hz, > are truly three phase. The discussion heats up when you are talking about a > phase to phase connection on a three phase distribution (208 or 400V). Is > this called single phase or two phase? It has been suggested that in the > European community it is called two phase, while in the U.S. we call it > single phase. I am looking for opinions or discussion on this issue. > > On a related note in the U.S. we have 240V 60Hz (two 120V drops) coming into > our into our homes. This is provided by a transformer with a center taped > winding. On the outside legs of the transformer we have 240V but between > either outside leg and neutral (center tap) we have 120V. I would call this > a single phase system with two additive (in phase) 120V windings. Again > others have called this two phase. > > My apologies to the group if this is a stupid question. Its just one of > those nagging questions. > > Rick Busche > Evans & Sutherland > Salt Lake City, Utah > > rbus...@es.com > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson:pstc_ad...@garretson.org > Dave Healddavehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
Hi Rick, I've heard the term "split-phase" applied to this sort of set-up. My opinion and not that of my employer. Regards, Kaz Gawrzyjal kazimier_gawrzy...@dell.com -Original Message- From: rbus...@es.com [mailto:rbus...@es.com] Sent: Wednesday, May 02, 2001 3:31 PM To: emc-p...@majordomo.ieee.org Subject: AC Power Primer? I am in the process of assisting our publications group with documenting an ac power configuration. As simple as this sounds, it turns out there are varying opinions in our engineering group regarding the naming convention for input power, in particular single phase verses two phase. We all probably agree that a phase to neutral connection is single phase and devices that use all thee phases, whether they are 208V 60Hz or 400V 50Hz, are truly three phase. The discussion heats up when you are talking about a phase to phase connection on a three phase distribution (208 or 400V). Is this called single phase or two phase? It has been suggested that in the European community it is called two phase, while in the U.S. we call it single phase. I am looking for opinions or discussion on this issue. On a related note in the U.S. we have 240V 60Hz (two 120V drops) coming into our into our homes. This is provided by a transformer with a center taped winding. On the outside legs of the transformer we have 240V but between either outside leg and neutral (center tap) we have 120V. I would call this a single phase system with two additive (in phase) 120V windings. Again others have called this two phase. My apologies to the group if this is a stupid question. Its just one of those nagging questions. Rick Busche Evans & Sutherland Salt Lake City, Utah rbus...@es.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: AC Power Primer?
Hi Rick: 1. Re phase-to-phase connection to 2 legs of a 3-phase system, I'd call it single phase. 2. The 120+120=240 system that enters our homes is commonly called "split-phase" because it is a single phase 240Vac circuit that happens to be split into 2 by the centre-tap to provide 120Vac circuits as well. Jim Eichner, P.Eng. Group Leader, Engineering Services Xantrex Technology Inc. Mobile Markets phone: (604) 422-2546 fax: (604) 420-1591 e-mail: jim.eich...@xantrex.com web: www.xantrex.com -Original Message- From: rbus...@es.com [mailto:rbus...@es.com] Sent: Wednesday, May 02, 2001 1:31 PM To: emc-p...@majordomo.ieee.org Subject: AC Power Primer? I am in the process of assisting our publications group with documenting an ac power configuration. As simple as this sounds, it turns out there are varying opinions in our engineering group regarding the naming convention for input power, in particular single phase verses two phase. We all probably agree that a phase to neutral connection is single phase and devices that use all thee phases, whether they are 208V 60Hz or 400V 50Hz, are truly three phase. The discussion heats up when you are talking about a phase to phase connection on a three phase distribution (208 or 400V). Is this called single phase or two phase? It has been suggested that in the European community it is called two phase, while in the U.S. we call it single phase. I am looking for opinions or discussion on this issue. On a related note in the U.S. we have 240V 60Hz (two 120V drops) coming into our into our homes. This is provided by a transformer with a center taped winding. On the outside legs of the transformer we have 240V but between either outside leg and neutral (center tap) we have 120V. I would call this a single phase system with two additive (in phase) 120V windings. Again others have called this two phase. My apologies to the group if this is a stupid question. Its just one of those nagging questions. Rick Busche Evans & Sutherland Salt Lake City, Utah rbus...@es.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
