RE: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
Thanks guys for all the feedback! Jim WD5JKO Also, Check out the following links. A 1000vA elgar is in the first link for $200.00 http://www.sg-photo.com/powersup.htm http://www.surplussales.com/PowerSupplies/PowerS-1.html > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED] > Sent: Saturday, January 18, 2003 10:09 AM > To: amradio@mailman.qth.net > Subject: Re: [AMRadio] Today's AC Mains voltage too high for many BA > Rigs > > > Hi John, > > I don't have a digital camera of my own, but can easily borrow > one and send > you a picture. They are heavy. About 70lbs. They use no > filtering. They are > high quality, audio power amplifiers, in series with the > secondary of a split > bobbin, shielded power transformer. The transformer is > responsible for most > of the weight. The amplifier can make about 70 volt ac, and is > connected in > series with about an 80 volt winding of the transformer. They use an > oscillator, that is PLL locked to the line, and the output of > this oscillator > is the reference to the amplifier. The amplifier will buck or boost, real > time, to make the output look just like the input. (the sine wave > oscillator) > The transformer in these units are beautiful. They have full faraday > shielding between primary and secondary, including shielded coax > type leads > in and out. The line is completely isolated from the load. The unit is > configurable to allow full isolation including it's own floating neutral. > These units are beautifully built, and were well over $1000 when > they were > new 25yrs ago, but they can be found today for about $35 on the > used market. > > The only thing I did before using them in the shack, was to > install 20amp EMI > filters on the input and output. This is to keep rf out of the > unit. I run > legal limit from time to time and didn't want rf getting in and > causing it to > misbehave. Although I have not tried running them without the > filters. The > units may work just fine without them. I mounted the input filter > directly on > the rear apron. I cut the power cord and ran it through the > filter first. The > output filter is identical to the input filter. I have a short power cord > (about 8") plugged into the back of the line conditioner, and the filters > output is connected to a power strip where I have all my radio > gear plugged > in. > > I'll send you a picture as soon as I can John. They are > distinctive looking > enough to spot them from a distance at a flea market. They are a > great asset > to any shack. > > 73, Ed > AA8TV > ___ > AMRadio mailing list > AMRadio@mailman.qth.net > http://mailman.qth.net/mailman/listinfo/amradio
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
Hi John, I don't have a digital camera of my own, but can easily borrow one and send you a picture. They are heavy. About 70lbs. They use no filtering. They are high quality, audio power amplifiers, in series with the secondary of a split bobbin, shielded power transformer. The transformer is responsible for most of the weight. The amplifier can make about 70 volt ac, and is connected in series with about an 80 volt winding of the transformer. They use an oscillator, that is PLL locked to the line, and the output of this oscillator is the reference to the amplifier. The amplifier will buck or boost, real time, to make the output look just like the input. (the sine wave oscillator) The transformer in these units are beautiful. They have full faraday shielding between primary and secondary, including shielded coax type leads in and out. The line is completely isolated from the load. The unit is configurable to allow full isolation including it's own floating neutral. These units are beautifully built, and were well over $1000 when they were new 25yrs ago, but they can be found today for about $35 on the used market. The only thing I did before using them in the shack, was to install 20amp EMI filters on the input and output. This is to keep rf out of the unit. I run legal limit from time to time and didn't want rf getting in and causing it to misbehave. Although I have not tried running them without the filters. The units may work just fine without them. I mounted the input filter directly on the rear apron. I cut the power cord and ran it through the filter first. The output filter is identical to the input filter. I have a short power cord (about 8") plugged into the back of the line conditioner, and the filters output is connected to a power strip where I have all my radio gear plugged in. I'll send you a picture as soon as I can John. They are distinctive looking enough to spot them from a distance at a flea market. They are a great asset to any shack. 73, Ed AA8TV
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
Hi Jim My situation is quite different from yours, but I thought that my experience might be useful to you. I use an old pole pig, in the power supply, used as a high voltage source, for a number of HF, VHF & UHF power amplifiers. The high voltage was initially excessive, so I used a 2 KVA varible auto transformer to reduce the supplys' output voltage. After experiencing problems with the vari-autoxfmr. (arcing at the brush), I replaced it with a fixed xfmr., that dropped the line voltage the desired amount. This lash-up has worked flawlessly, for appx. 20 years, AND as a side benefit, the no load to full load voltage regulation, of the HV supply, improved very noticeably! Why? Because, as the load, on the power supply, and thus on the "bucking transformer" increases, the output of the latter decreases, decreasing the amount of "buck". As a result, the voltage delivered to the pole pig increases, producing a sort of compensation. Another consideration would be that it would be a lot less effort to drop the line voltage, external to your equipment, relative to the effort required to modify all the individual pieces of equipment involved. A heavy duty filament transformer should do nicely. In my case, I had to drop my line voltage appx. 30 volts, or so, thus I used a power xfmr., from a defunct paper tape reader, that happened to be available. GL & 73 de Ron n4gjv --- Jim Candela <[EMAIL PROTECTED]> wrote: > Follow-Up on 20A. > I have an observation that is perplexing me. > Some of my old AM Boat > Anchor gear was designed in the days when the AC > mains power was lower. For > example on one of my Central Electronics 20a 's, >I measured the > filament voltage (non-RMS DVM), and it came out to > 6.9 vac with a AC line > voltage of 123 volts. I had to lower my ac mains > with a variac to 112 vac to > get the filaments down to the nominal 6.3 volts. > > This brings up a couple of issues: > > 1.) The filaments running ~ 10% high may have more > emission, but cathode > longevity may suffer along with more likely heater > to cathode shorts. > > 2.) The AC power transformers may not have adequate > flux BH headroom, and > could start to saturate, leading to high AC input > current, and hot > magnetics. > > 3.) The High voltage may be beyond the ratings of > the components (too much > voltage) which may lead to higher heat dissipation. > For example, > electrolytic capacitors may see too much voltage. > This is especially true > when solid state power supplies are used with vacuum > tube circuits. The > voltage soars to the peak AC value until the tube > heaters warm up enough to > pull current. The higher tube element voltages may > also (if unregulated) > move the DC operation points to dangerously unstable > levels. For example, a > 10% rise in the G2 voltage (say 400 to 440) of a > Beam Power tube can > increase the DC operating point such that the plate > dissipation is too high > leading to a thermal run away condition. > > My first thought of attack concerning my 20A was to > add resistance to the > filament wiring. This is doable so long as the ac > mains voltage is > reasonably constant. The DC voltage issue can be > solved in other ways, such > as regulating the G1 fixed bias, and the G2 screen > voltage to my 7591 beam > power tubes. It seems that when the ac mains > increases, the G1 fixed bias > goes more negative, and the screen G2 goes more > positive. The sensitivity to > G2 is greater than G1, so the plate current varies > quite a bit with a small > change in ac mains voltage. Just thinking about > this, I could add some gain > to the G1 potential VS ac mains voltage change to > cancel out the G2 effect > on plate current. A little bit of cathode bias to > the 7591's might also help > with stabilizing the DC operating point as well as > adding a little > degeneration (gain, and distortion reduction). This > approach might be an > option to regulating both element voltages. I have > plenty of headroom with > the electrolytics. > > Another option would be to add a multi-tap > buck/boost transformer so that I > can accommodate a variety of AC mains voltages, and > still get the nominal > 6.3 volts ac to the filaments. This need not be > large, and could be > installed within the rig. A 12Vct 2A transformer > could be used to add 6, 12, > or subtract 6, 12 volts from the AC mains input. It > would require a fancy > switch (maybe 2), or network of jumpers to work > however. > > What I have ended up doing was to install a 5 amp > variac to a 6 plug outlet > strip. I am currently running my RCA AR88 receiver, > CE 20A, BC-458 VFO, and > a rack mount Kepco 200 volt power supply all off the > strip. I set the variac > to 114 volts. The AC drops to 112 with my linear set > to 200 watts carrier > output. Now I need to find out about my Gonset > GSB-201 linear (4 X 572B), > and determine what filament voltage is on the > 572B's. Hey at $50 bucks each > (today's pr
RE: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
I don't know if I have ever seen one of these Elgar line conditioners but they sound cool. I bet they are real heavy though. If you ship them Ed, be sure the other guy pays the freight. HIHI I wonder how they get the sine wave as clean as you say there must be some resonate filters that add more weight. I would like to have one but how would I get it here to south Texas. Seriously Ed, send a picture if you have one, of what one looks like so I can keep an eye out for one down here some where. EMAIL: mailto:[EMAIL PROTECTED] TNX John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Friday, January 17, 2003 10:58 PM To: amradio@mailman.qth.net Subject: Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs For what it's worth.. I have four Elgar line conditioners. Two that work perfectly, and two for parts units. They are the 6000B series. I didn't pay more than $35 for any of the units. The will input 105-125vac and output 110-120vac (user adjustable) with better than .025% regulation, line or load, with less than .1% distortion. They will react to incoming transients, and fix it, within 20 microseconds! You can supply it absolute garbage, and it will output a pure, regulated sine wave, at up to 10 amps continuous. All my boatanchors see a steady110vac regardless of the line fluctuations. I have also seen as much as 130vac here. I'm convinced the power companies are doing this deliberately to generate more revenue. After using these conditioners (since the mid 70's) I wouldn't even consider plugging my precious old rigs directly into the line, unprotected. You wouldn't believe how stable the vfo looks on a DX-100 when the line voltage doesn't vary more than 30mv!! (The published input range is 95-115, 105-125, or 115-135 user selectable, but they will actually handle 95-135vac on the middle setting if you're less than the 10amps max load) 73, Ed AA8TV Lakewood, Ohio ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio
RE: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
You may be right there Gary. I don't know a lot about the different types of meters. I was using a RCA Senior VoltOhmist (AC measure by rectification and filter) which actually reads rectified and filtered PTP and is calibrated in PTP as well as RMS, For this meter, the RMS is only accurate if the voltage is a sine wave while the PTP is actually Peak TO Peak of what ever the wave form is. In the case of the squared AC output, a capacitor input filter on the rectified output will charge to the Peak of the wave, regardless of the shape. This means that if the thing was to be used for delivery of DC with capacitor input filtering, it would be the same DC regardless of wave shape. PTP voltages being the same: The actual power delivered by the AC output to a resistive load, such as heaters, is more with the squared wave because the average level of the E*I is greater for a Square Wave than for a Sine Wave. I would like to know more about the iron vane movement. Does it work via induced eddy currents that cause opposing magnetic fields? John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gary Schafer Sent: Friday, January 17, 2003 10:22 PM To: amradio@mailman.qth.net Subject: Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs Hi John, I think that an "iron vane" type meter to read the voltage will give the true rms voltage no matter what the wave form is. 73 Gary K4FMX
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
For what it's worth.. I have four Elgar line conditioners. Two that work perfectly, and two for parts units. They are the 6000B series. I didn't pay more than $35 for any of the units. The will input 105-125vac and output 110-120vac (user adjustable) with better than .025% regulation, line or load, with less than .1% distortion. They will react to incoming transients, and fix it, within 20 microseconds! You can supply it absolute garbage, and it will output a pure, regulated sine wave, at up to 10 amps continuous. All my boatanchors see a steady110vac regardless of the line fluctuations. I have also seen as much as 130vac here. I'm convinced the power companies are doing this deliberately to generate more revenue. After using these conditioners (since the mid 70's) I wouldn't even consider plugging my precious old rigs directly into the line, unprotected. You wouldn't believe how stable the vfo looks on a DX-100 when the line voltage doesn't vary more than 30mv!! (The published input range is 95-115, 105-125, or 115-135 user selectable, but they will actually handle 95-135vac on the middle setting if you're less than the 10amps max load) 73, Ed AA8TV Lakewood, Ohio
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
Hi John, I think that an "iron vane" type meter to read the voltage will give the true rms voltage no matter what the wave form is. 73 Gary K4FMX John E. Coleman wrote: I haven't seen any post about the saturated core constant voltage XFMRs. I use them a lot. They keep the OSCs on the RCVR and XMTR stable. I have never used one on a filament source for a directly heated cathode tube but since the output wave form is not a sine wave but somewhat squared due to the saturation of the core, I would assume the voltage would need to be reduced to arrive at the same heat on the filaments. They were easy to make. A lot of the hybrid TVs of old use power XFMRs with saturated core technology to keep the output voltages constant so that the picture didn't shrink or jump when the air conditioners or heaters would kick on. There was a 2 or 4 uF oil filled cap across part of a secondary winding that some what resonated and saturated the core. The input voltage could vary for 100 - 130 with very little change in the DC from the rectifiers. I would use the filament winds to buck or add to the output to get it where I wanted it to be. With one manufacture, I actually came up with 115 volts as read on a RMS meter. The scope showed it to be clipped about 10-15 percent. A light bulb test was made and found to be brighter on the constant voltage XFMT than on a variac delivering the same RMS measured voltage. This could be compensated for I would think. John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Donald Chester Sent: Friday, January 17, 2003 11:53 AM To: amradio@mailman.qth.net Subject: Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs I have the problem here. I have seen the voltage as low as 108v and as high is 125. My main transmitter has a rheostat on the tube filament transformer line feeding several transformers, but I have the same problem, having to keep a constant eye on the thing and frequent adjustment. Incorrect voltage won't burn out tubes right away, but the manufacturers have warned for years that this will shorten useful tube life. One solution I have thought of, and probably have all the parts for, would be an automatic voltage regulator using a variac and reversible motor. I have a relay that looks like a meter, but the pointer has two sets of contacts, one of which will engage wenever the pointer is above or below the set value which is adjustable with a knob near the zeroing screw. It's just a matter of figuring out exactly how to build the thing and putting it together. Minus the special relay, I have thought about using a VR tube and comparing its voltage output to that of an unregulated power supply with the same nominal output voltage. Of course, it could also be done using solid state components. One thought about using a variac. With most of the ones I have used, even the HD ones, the regulation sucks. A tapped autoformer with a heavy duty switch is better. Instead of using the variac to drive the equipment direcly, it would be better to use a large, high current, low voltage transformer@ about 15-24 vac/ 30 amps as a bucking transformer and use the variac in the primaryof the transformer. That way you get better resolution of voltage and better regulation. The problem with variacs is the carbon brush contact. It must have a certain amount of resistance so that shorted adjacent turns don't overheat, since the wiper contact must make before break to assure uninterrupted output as the voltage is varied. Don K4KYV ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio
RE: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
I haven't seen any post about the saturated core constant voltage XFMRs. I use them a lot. They keep the OSCs on the RCVR and XMTR stable. I have never used one on a filament source for a directly heated cathode tube but since the output wave form is not a sine wave but somewhat squared due to the saturation of the core, I would assume the voltage would need to be reduced to arrive at the same heat on the filaments. They were easy to make. A lot of the hybrid TVs of old use power XFMRs with saturated core technology to keep the output voltages constant so that the picture didn't shrink or jump when the air conditioners or heaters would kick on. There was a 2 or 4 uF oil filled cap across part of a secondary winding that some what resonated and saturated the core. The input voltage could vary for 100 - 130 with very little change in the DC from the rectifiers. I would use the filament winds to buck or add to the output to get it where I wanted it to be. With one manufacture, I actually came up with 115 volts as read on a RMS meter. The scope showed it to be clipped about 10-15 percent. A light bulb test was made and found to be brighter on the constant voltage XFMT than on a variac delivering the same RMS measured voltage. This could be compensated for I would think. John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Donald Chester Sent: Friday, January 17, 2003 11:53 AM To: amradio@mailman.qth.net Subject: Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs I have the problem here. I have seen the voltage as low as 108v and as high is 125. My main transmitter has a rheostat on the tube filament transformer line feeding several transformers, but I have the same problem, having to keep a constant eye on the thing and frequent adjustment. Incorrect voltage won't burn out tubes right away, but the manufacturers have warned for years that this will shorten useful tube life. One solution I have thought of, and probably have all the parts for, would be an automatic voltage regulator using a variac and reversible motor. I have a relay that looks like a meter, but the pointer has two sets of contacts, one of which will engage wenever the pointer is above or below the set value which is adjustable with a knob near the zeroing screw. It's just a matter of figuring out exactly how to build the thing and putting it together. Minus the special relay, I have thought about using a VR tube and comparing its voltage output to that of an unregulated power supply with the same nominal output voltage. Of course, it could also be done using solid state components. One thought about using a variac. With most of the ones I have used, even the HD ones, the regulation sucks. A tapped autoformer with a heavy duty switch is better. Instead of using the variac to drive the equipment direcly, it would be better to use a large, high current, low voltage transformer@ about 15-24 vac/ 30 amps as a bucking transformer and use the variac in the primaryof the transformer. That way you get better resolution of voltage and better regulation. The problem with variacs is the carbon brush contact. It must have a certain amount of resistance so that shorted adjacent turns don't overheat, since the wiper contact must make before break to assure uninterrupted output as the voltage is varied. Don K4KYV
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
From: "Jeffrey J. May" <[EMAIL PROTECTED]> ... I am thinking about using two heavy duty automatic regulated Variacs on each line that will automatically adjust within a set range..pricey though..problem is that my line voltage varies enough that I am adjusting too often manually..Jeff..W0XV I have the problem here. I have seen the voltage as low as 108v and as high is 125. My main transmitter has a rheostat on the tube filament transformer line feeding several transformers, but I have the same problem, having to keep a constant eye on the thing and frequent adjustment. Incorrect voltage won't burn out tubes right away, but the manufacturers have warned for years that this will shorten useful tube life. One solution I have thought of, and probably have all the parts for, would be an automatic voltage regulator using a variac and reversible motor. I have a relay that looks like a meter, but the pointer has two sets of contacts, one of which will engage wenever the pointer is above or below the set value which is adjustable with a knob near the zeroing screw. It's just a matter of figuring out exactly how to build the thing and putting it together. Minus the special relay, I have thought about using a VR tube and comparing its voltage output to that of an unregulated power supply with the same nominal output voltage. Of course, it could also be done using solid state components. One thought about using a variac. With most of the ones I have used, even the HD ones, the regulation sucks. A tapped autoformer with a heavy duty switch is better. Instead of using the variac to drive the equipment direcly, it would be better to use a large, high current, low voltage transformer@ about 15-24 vac/ 30 amps as a bucking transformer and use the variac in the primaryof the transformer. That way you get better resolution of voltage and better regulation. The problem with variacs is the carbon brush contact. It must have a certain amount of resistance so that shorted adjacent turns don't overheat, since the wiper contact must make before break to assure uninterrupted output as the voltage is varied. Don K4KYV _ MSN 8 helps eliminate e-mail viruses. Get 2 months FREE* http://join.msn.com/?page=features/virus
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
I am not an engineer but have visited with some concerning this issue. Anyone with 129 volts at the outlets should call their electric supply company and have it checked after they check the calibration of their meter. Pretty much the standard today is 120 volts at your outlets. In my previous location which was rural and quite a way from a substation, I had what I thought was low voltage so I called the company. The guy measured it at 119 volts and stated that it would vary between 115 and 120 on a regular basis. Someone who has 129 probably lives nears a capacitor bank or in an area of heavy usage during peak days. That can be changed and should be if it is truly that high. There are taps on the house transformer to adjust for that. The electric man also stated that variations of 10% were normal and expected. At 115 volts nominal that is a 11.5 volt variation which equipment manufacturers should have taken into account in the design of the equipment. On the higher end equipment, taps on the primary of the power transformer were provided to address the issue. My B&W 5100B has a switch for 107 and 117 volt mains. So with 117 plus the high variation that makes it about the 129 someone mentioned. These variations should be temporary and if I read 125 or more volts on my main regularly, I would check the calibration of my equipment first then contact the electric company. If we read our manuals voltage chart, we find that voltage tolerances are 10% there. Add that to any variations of the supply and you can have pretty high voltage. Good equipment and tube manufacturers took this into account. 73 Jim de W5JO - Original Message - From: "Todd Bigelow - PS" <[EMAIL PROTECTED]> > I'm pretty much with you on this one, Brett - although I can see a problem for > equipment that is older than the 115v standard running at 129V! Yipers! > > I'm in the middle of Vermont using the largest power company in the state, CVPS. > I have a plug-in AC meter which I use to monitor the line voltage. It stays > right around 115-117v. I don't recall ever seeing it drop below 112 or go up to > or over 120. Another ham I know lives north of me maybe 35 miles and has a rural > electric company. His power tends to run low. > > > Todd/'Boomer' KA1KAQ > > ___ > AMRadio mailing list > AMRadio@mailman.qth.net > http://mailman.qth.net/mailman/listinfo/amradio >
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
Great idea, but how do you work out phaseing? I've been toying with that idea, but had decided I'd have to settle for 125-240 as adjustment range. Gary "Jeffrey J. May" <[EMAIL PROTECTED]> wrote:Wayne..same issue here..rural area and voltage varies from 119 to 125V..so bucking transformer doesn't cut it..like you I use a large 115V variac ..also use two heavy duty 115vV variacs on the 240V line..split the line..variac each side and re-combine..have a very accurate digital line voltage monitor on each line.. I am thinking about using two heavy duty automatic regulated Variacs on each line that will automatically adjust within a set range..pricey though..problem is that my line voltage varies enough that I am adjusting too often manually..Jeff..W0XV - Original Message - From: "Sara & Wayne Steiner" To: Sent: Friday, January 17, 2003 6:50 AM Subject: Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs > Jim , > I have had this problem one way or another for years ever since I have > started to use the old boat anchors. There are times when my line voltage > is as high as 129 v! This really plays havoc with a rig like the B&W 5100. > The bucking xfmr seems to work OK for some other vintage enthusiests in the > Mo,Kans area, but since my line voltage (rural elec co-op) varies a lot I > have resorted to variacs.One treasure I have is a 22amp unit which can > handle a bunch of boat anchors at one time. > 73 > Wayne, N0TE > > ___ > AMRadio mailing list > AMRadio@mailman.qth.net > http://mailman.qth.net/mailman/listinfo/amradio > ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio - Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now --- StripMime Report -- processed MIME parts --- multipart/alternative text/plain (text body -- kept) text/html The reason this message is shown is because the post was in HTML or had an attachment. Attachments are not allowed. To learn how to post in Plain-Text go to: http://www.expita.com/nomime.html ---
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
Brett Gazdzinski wrote: > I ignore it. > Never had a problem. > If you are running equipment you have to worry about because the line > voltage > is slightly high, its bad news, things are supposed to have some headroom... I'm pretty much with you on this one, Brett - although I can see a problem for equipment that is older than the 115v standard running at 129V! Yipers! I'm in the middle of Vermont using the largest power company in the state, CVPS. I have a plug-in AC meter which I use to monitor the line voltage. It stays right around 115-117v. I don't recall ever seeing it drop below 112 or go up to or over 120. Another ham I know lives north of me maybe 35 miles and has a rural electric company. His power tends to run low. But as Brett says, wasn't most equipment built with some amount of tolerance for over/under voltage? Not a lot, but certainly a couple-few volts? Most of the gear I have states clearly on it 115VAC. When did this standard come along, sometime in the '40s? I'd find it hard to believe that the 'primary voltate' around 1960 was 108 volts as one response to another list stated, but I wasn't around until '61 so I can't say for sure. At any rate, unless you have wildly fluctuating voltage like some do in rural areas (129v is TOO high IMHO) or the gear is quite old, like from the days of 110v, I can't see that it would be much of a problem. 110v gear I'd use a variac for, not so much for the few volts of higher voltage but more because the technology and processes weren't as refined then so it's probably a lot easier to fry something. Things like insulation in transformers comes to mind. What sayeth the enginners and electricians out there? What is considered a safe range for 115vac? +/- 5 volts? When did the 115v standard come into being, and what were the design standards then as far as voltage tolerance? It would seem to me that some out there have a legitimate reason to be concerned, but probably most of us don't. Todd/'Boomer' KA1KAQ
RE: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
What a wide collection of replies--bucking transformers, variacs and trust to luck--you have your choice. My shack is a mixed bag. I have about 20 stations set up. Most of these are powered on variacs permanently set to deliver 105V. But some of the rigs are more recently constructed homebrew units or they have output voltage controls on their power supplies and so I run them straight off the line. The few solid state items here also run directly off the line. Everything is switched through a sub-panel so that you can't just walk up to a piece of gear and turn it on--you have to turn on the panel first. I did that because I have kids who "look with their hands". But I put EMI/RFI filtering and circuit breakers into each of the panels and variac boxes too. So the panels do more than just switching. I think the only truth here is that you can't take line power for granted. It's worth the time to think through the power situation and take no chances. My 2 cents. 73, Don Merz, N3RHT -Original Message- From: Brett Gazdzinski [mailto:[EMAIL PROTECTED] Sent: Friday, January 17, 2003 8:15 AM To: amradio@mailman.qth.net Subject: RE: [AMRadio] Today's AC Mains voltage too high for many BA Rigs I ignore it. Never had a problem. I have two 32v3 transmitters, that are all solid stated, and run on the high voltage tap, no problems for over 15 years, not a single tube has gone south. I have an R390 that has not needed a tube or anything else, for over 15 years. I have an sx17 that has not needed any tubes or had problems, I have a Scott SLRM that has the filaments in series, no power transformers at all, no tube problems. My line voltage fluctuates wildly at times, for some reason, loads dim the lights, they will even pulse to some loads like my compressor running, or the washing machine. Never burnt any tube out in 15 to 20 years of frequent use. If something was marginal enough to go because the line voltage is a bit high, I want it replaced anyway. I wonder just how long this equipment can go without any tube failures. I have blown out some old scruffy PA amp tubes like 4-400,s and 6146,s but they were broadcast pulls I think, or bad to start with. ...$5.00 ham fest specials. If you are running equipment you have to worry about because the line voltage is slightly high, its bad news, things are supposed to have some headroom... Brett N2DTS > > Follow-Up on 20A. > I have an observation that is perplexing me. Some of my > old AM Boat > Anchor gear was designed in the days when the AC mains power > was lower. For > example on one of my Central Electronics 20a 's,I measured the > filament voltage (non-RMS DVM), and it came out to 6.9 vac > with a AC line > voltage of 123 volts. I had to lower my ac mains with a > variac to 112 vac to > get the filaments down to the nominal 6.3 volts. > > This brings up a couple of issues: > > 1.) The filaments running ~ 10% high may have more emission, > but cathode > longevity may suffer along with more likely heater to cathode shorts. > > 2.) The AC power transformers may not have adequate flux BH > headroom, and > could start to saturate, leading to high AC input current, and hot > magnetics. > > 3.) The High voltage may be beyond the ratings of the > components (too much > voltage) which may lead to higher heat dissipation. For example, > electrolytic capacitors may see too much voltage. This is > especially true > when solid state power supplies are used with vacuum tube > circuits. The > voltage soars to the peak AC value until the tube heaters > warm up enough to > pull current. The higher tube element voltages may also (if > unregulated) > move the DC operation points to dangerously unstable levels. > For example, a > 10% rise in the G2 voltage (say 400 to 440) of a Beam Power tube can > increase the DC operating point such that the plate > dissipation is too high > leading to a thermal run away condition. > > My first thought of attack concerning my 20A was to add > resistance to the > filament wiring. This is doable so long as the ac mains voltage is > reasonably constant. The DC voltage issue can be solved in > other ways, such > as regulating the G1 fixed bias, and the G2 screen voltage to > my 7591 beam > power tubes. It seems that when the ac mains increases, the > G1 fixed bias > goes more negative, and the screen G2 goes more positive. The > sensitivity to > G2 is greater than G1, so the plate current varies quite a > bit with a small > change in ac mains voltage. Just thinking about this, I could > add some gain > to the G1 potential VS ac mains voltage change to cancel out > the G2 effect > on plate current. A little bit of cathode bias to the 7591's > might also help > with stabilizing
RE: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
I ignore it. Never had a problem. I have two 32v3 transmitters, that are all solid stated, and run on the high voltage tap, no problems for over 15 years, not a single tube has gone south. I have an R390 that has not needed a tube or anything else, for over 15 years. I have an sx17 that has not needed any tubes or had problems, I have a Scott SLRM that has the filaments in series, no power transformers at all, no tube problems. My line voltage fluctuates wildly at times, for some reason, loads dim the lights, they will even pulse to some loads like my compressor running, or the washing machine. Never burnt any tube out in 15 to 20 years of frequent use. If something was marginal enough to go because the line voltage is a bit high, I want it replaced anyway. I wonder just how long this equipment can go without any tube failures. I have blown out some old scruffy PA amp tubes like 4-400,s and 6146,s but they were broadcast pulls I think, or bad to start with. ...$5.00 ham fest specials. If you are running equipment you have to worry about because the line voltage is slightly high, its bad news, things are supposed to have some headroom... Brett N2DTS > > Follow-Up on 20A. > I have an observation that is perplexing me. Some of my > old AM Boat > Anchor gear was designed in the days when the AC mains power > was lower. For > example on one of my Central Electronics 20a 's,I measured the > filament voltage (non-RMS DVM), and it came out to 6.9 vac > with a AC line > voltage of 123 volts. I had to lower my ac mains with a > variac to 112 vac to > get the filaments down to the nominal 6.3 volts. > > This brings up a couple of issues: > > 1.) The filaments running ~ 10% high may have more emission, > but cathode > longevity may suffer along with more likely heater to cathode shorts. > > 2.) The AC power transformers may not have adequate flux BH > headroom, and > could start to saturate, leading to high AC input current, and hot > magnetics. > > 3.) The High voltage may be beyond the ratings of the > components (too much > voltage) which may lead to higher heat dissipation. For example, > electrolytic capacitors may see too much voltage. This is > especially true > when solid state power supplies are used with vacuum tube > circuits. The > voltage soars to the peak AC value until the tube heaters > warm up enough to > pull current. The higher tube element voltages may also (if > unregulated) > move the DC operation points to dangerously unstable levels. > For example, a > 10% rise in the G2 voltage (say 400 to 440) of a Beam Power tube can > increase the DC operating point such that the plate > dissipation is too high > leading to a thermal run away condition. > > My first thought of attack concerning my 20A was to add > resistance to the > filament wiring. This is doable so long as the ac mains voltage is > reasonably constant. The DC voltage issue can be solved in > other ways, such > as regulating the G1 fixed bias, and the G2 screen voltage to > my 7591 beam > power tubes. It seems that when the ac mains increases, the > G1 fixed bias > goes more negative, and the screen G2 goes more positive. The > sensitivity to > G2 is greater than G1, so the plate current varies quite a > bit with a small > change in ac mains voltage. Just thinking about this, I could > add some gain > to the G1 potential VS ac mains voltage change to cancel out > the G2 effect > on plate current. A little bit of cathode bias to the 7591's > might also help > with stabilizing the DC operating point as well as adding a little > degeneration (gain, and distortion reduction). This approach > might be an > option to regulating both element voltages. I have plenty of > headroom with > the electrolytics. > > Another option would be to add a multi-tap buck/boost > transformer so that I > can accommodate a variety of AC mains voltages, and still get > the nominal > 6.3 volts ac to the filaments. This need not be large, and could be > installed within the rig. A 12Vct 2A transformer could be > used to add 6, 12, > or subtract 6, 12 volts from the AC mains input. It would > require a fancy > switch (maybe 2), or network of jumpers to work however. > > What I have ended up doing was to install a 5 amp variac to a > 6 plug outlet > strip. I am currently running my RCA AR88 receiver, CE 20A, > BC-458 VFO, and > a rack mount Kepco 200 volt power supply all off the strip. I > set the variac > to 114 volts. The AC drops to 112 with my linear set to 200 > watts carrier > output. Now I need to find out about my Gonset GSB-201 linear > (4 X 572B), > and determine what filament voltage is on the 572B's. Hey at > $50 bucks each > (today's prices) I don't want the filaments burning at 7.0 volts (6.3 > nominal??). I will need a 15 amp solution to dropping the > voltage to the > Gonset should the filaments be too hot. > > Do any of you fine folk have this problem, and if so, how are > you dealing > with it? > > Jim, > WD5JKO >
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
Folks, The power company loves higher delivery voltages - makes your Kwh meter turn faster since most of your house loads are resistive (voltage sensitive). Think about it. I'd like to run my entire house on 115 volts, even the bulbs would last longer. One 15Kva tapped transformer would do it but then you need to figure in the transformer losses. John KF2JQ Sara & Wayne Steiner wrote: > Jim , > I have had this problem one way or another for years ever since I have > started to use the old boat anchors. There are times when my line voltage > is as high as 129 v! This really plays havoc with a rig like the B&W 5100. > The bucking xfmr seems to work OK for some other vintage enthusiests in the > Mo,Kans area, but since my line voltage (rural elec co-op) varies a lot I > have resorted to variacs.One treasure I have is a 22amp unit which can > handle a bunch of boat anchors at one time. > 73 > Wayne, N0TE > > ___ > AMRadio mailing list > AMRadio@mailman.qth.net > http://mailman.qth.net/mailman/listinfo/amradio
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
Wayne..same issue here..rural area and voltage varies from 119 to 125V..so bucking transformer doesn't cut it..like you I use a large 115V variac ..also use two heavy duty 115vV variacs on the 240V line..split the line..variac each side and re-combine..have a very accurate digital line voltage monitor on each line.. I am thinking about using two heavy duty automatic regulated Variacs on each line that will automatically adjust within a set range..pricey though..problem is that my line voltage varies enough that I am adjusting too often manually..Jeff..W0XV - Original Message - From: "Sara & Wayne Steiner" <[EMAIL PROTECTED]> To: Sent: Friday, January 17, 2003 6:50 AM Subject: Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs > Jim , > I have had this problem one way or another for years ever since I have > started to use the old boat anchors. There are times when my line voltage > is as high as 129 v! This really plays havoc with a rig like the B&W 5100. > The bucking xfmr seems to work OK for some other vintage enthusiests in the > Mo,Kans area, but since my line voltage (rural elec co-op) varies a lot I > have resorted to variacs.One treasure I have is a 22amp unit which can > handle a bunch of boat anchors at one time. > 73 > Wayne, N0TE > > ___ > AMRadio mailing list > AMRadio@mailman.qth.net > http://mailman.qth.net/mailman/listinfo/amradio >
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
Jim , I have had this problem one way or another for years ever since I have started to use the old boat anchors. There are times when my line voltage is as high as 129 v! This really plays havoc with a rig like the B&W 5100. The bucking xfmr seems to work OK for some other vintage enthusiests in the Mo,Kans area, but since my line voltage (rural elec co-op) varies a lot I have resorted to variacs.One treasure I have is a 22amp unit which can handle a bunch of boat anchors at one time. 73 Wayne, N0TE
[AMRadio] Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
In a message dated 1/16/03 8:58:17 PM, [EMAIL PROTECTED] writes (in part): > Jim, > A familiar problem. > Had an old Westinghouse RBM rcvr that was loosing tubes... > All, Familiar problem indeed. The manuals for my SX-9 and SX16 receivers call for 110 vac input! I use an RCA WP-24A "High-Low" isolation transformer to drop my 122 vac line voltage when running the older stuff. Dennis D. W7QHO Glendale, CA --- StripMime Report -- processed MIME parts --- multipart/alternative text/plain (text body -- kept) text/html The reason this message is shown is because the post was in HTML or had an attachment. Attachments are not allowed. To learn how to post in Plain-Text go to: http://www.expita.com/nomime.html ---
Re: [AMRadio] Today's AC Mains voltage too high for many BA Rigs
Jim, A familiar problem. Had an old Westinghouse RBM rcvr that was loosing tubes till I found the fil was at 7v. WOW! Looked at the P.S. tag and ac input was spec'd at 115 v while my line was about >125. Found an old TV compensation transformer with a +/- 10 v switch . Took care of that. There can be found 5-10 amp isolation trans primarily for using with overseas 100v ac appliances as well as tapped autotrans with a range of compensation. Look for them in the surplus houses and travel suppliers. I have played with some large resonant 20a stabilizer units but they were objectionally noisy as well as heat producing and reflected the adjustmnt as a higher current draw that on a soft wall circuit just compounded the problem. My personal preference is the good old 20a autotran which does need to be fiddled with but can get whatever you need. The small 10v step downs are fine for receivers etc but get expensive in high current sizes. Have never tried the buck/ boost hookup but my line voltage can vary more than 15v throughout the day to say nothing abt the summer brownout season so a variable works best for me. Stable line voltage is a major problem with most tube testers as well since the line adjust is just a reostat on the trans pri. I run the adjust all the way up and use the bench autotran to adjust to set line. Good luck! Bill KB3DKS --- StripMime Report -- processed MIME parts --- multipart/alternative text/plain (text body -- kept) text/html The reason this message is shown is because the post was in HTML or had an attachment. Attachments are not allowed. To learn how to post in Plain-Text go to: http://www.expita.com/nomime.html ---
