Re: [Emc-users] Single to Three Phase Rotary Converters
I use craigslist to give things like that a new zipcode... John gene heskett wrote: On Monday, April 04, 2011 10:00:16 AM John Thornton did opine: No one said you have to turn it on once it is built. John True, but short of more buildings, anything else I get will need a place in out of the weather. This postage stamp, trapezoidal shaped lot has 4 outbuildings on it now. It seems like stuff I buy, is here forever. I have had some tools sitting under a tarp in the driveway with 4 Sale signs on them for over a year, no nibbles. Examples: A 12 Craftsman tilting head bandsaw I use for a power hacksaw occasionally, runs well, with over a dozen new and used blades, $200 A 6 Dewalt VS benchtop jointer on a stand w/2 sets new blades, $240new, $60. The VS died and is bypassed. A Craftsman dovetail jig, $80new, $20, no bit. A 10 BD/Dewalt radial arm saw with oversized table, works well, $100 The latter is under foot in the shop building. Listed on the local radio station swap shop program for several months last summer, not even a phone call. Yard sale signs posted most of last summer. Not even a motorized gawker. Which amazes me, this is yard sales by the dozens all summer country. -- Xperia(TM) PLAY It's a major breakthrough. An authentic gaming smartphone on the nation's most reliable network. And it wants your games. http://p.sf.net/sfu/verizon-sfdev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Tuesday, April 05, 2011 11:38:20 AM John Thornton did opine: I use craigslist to give things like that a new zipcode... John Humm, that hadn't crossed my alleged mind, John, thanks. -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html RIP is irrelevant. Spoofing is futile. Your routes will be aggregated. -- Alex Yuriev -- Xperia(TM) PLAY It's a major breakthrough. An authentic gaming smartphone on the nation's most reliable network. And it wants your games. http://p.sf.net/sfu/verizon-sfdev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
John, I live on the edge of civilization and my next door neighbor was a house builder. That didn't work out with the complete stall in construction in the Midwest, so he put a bunch of his tools up for sale. I didn't realize that until the sale had been going on in his driveway for 6+ hours. Still, he simply could not sell some things including a 1 hp commercial grade air compressor - the wheelbarrow type - purchased for $75, and a Delta Unisaw Tablesaw - purchased for $100! The used tool market is really in the dumper up here and that may be why you have having problems getting rid of your tools. Plus they aren't teaching woodshop or metalshop in the high schools any longer up here so the younger kids simply have no idea how to run a saw or do the things that many of us take for granted. Many (but not all) of them think that only contractors use tools like that. Dave On 4/5/2011 8:07 AM, John Thornton wrote: I use craigslist to give things like that a new zipcode... John gene heskett wrote: On Monday, April 04, 2011 10:00:16 AM John Thornton did opine: No one said you have to turn it on once it is built. John True, but short of more buildings, anything else I get will need a place in out of the weather. This postage stamp, trapezoidal shaped lot has 4 outbuildings on it now. It seems like stuff I buy, is here forever. I have had some tools sitting under a tarp in the driveway with 4 Sale signs on them for over a year, no nibbles. Examples: A 12 Craftsman tilting head bandsaw I use for a power hacksaw occasionally, runs well, with over a dozen new and used blades, $200 A 6 Dewalt VS benchtop jointer on a stand w/2 sets new blades, $240new, $60. The VS died and is bypassed. A Craftsman dovetail jig, $80new, $20, no bit. A 10 BD/Dewalt radial arm saw with oversized table, works well, $100 The latter is under foot in the shop building. Listed on the local radio station swap shop program for several months last summer, not even a phone call. Yard sale signs posted most of last summer. Not even a motorized gawker. Which amazes me, this is yard sales by the dozens all summer country. -- Xperia(TM) PLAY It's a major breakthrough. An authentic gaming smartphone on the nation's most reliable network. And it wants your games. http://p.sf.net/sfu/verizon-sfdev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Xperia(TM) PLAY It's a major breakthrough. An authentic gaming smartphone on the nation's most reliable network. And it wants your games. http://p.sf.net/sfu/verizon-sfdev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On 04/03/2011 05:29 PM, gene heskett wrote: On my BP Series 1 I use an Automation Direct GS2 VFD as it is only 1.5hp for the spindle and they are cost effective way to get up to 3hp 3 phase from single phase. I'd have to agree, and wish I had that big a mill, sniff... 15 HP is gonna be a little large for yer mini mill. Just sayin'... ;-) Mark -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Monday, April 04, 2011 05:42:05 AM Mark Wendt did opine: On 04/03/2011 05:29 PM, gene heskett wrote: On my BP Series 1 I use an Automation Direct GS2 VFD as it is only 1.5hp for the spindle and they are cost effective way to get up to 3hp 3 phase from single phase. I'd have to agree, and wish I had that big a mill, sniff... 15 HP is gonna be a little large for yer mini mill. Just sayin'... ;-) Mark Yep. But I've been drooling over bigger stuff. ;-) -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html The geeks shall inherit the earth. -- Karl Lehenbauer -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On 04/04/2011 05:43 AM, gene heskett wrote: On Monday, April 04, 2011 05:42:05 AM Mark Wendt did opine: On 04/03/2011 05:29 PM, gene heskett wrote: On my BP Series 1 I use an Automation Direct GS2 VFD as it is only 1.5hp for the spindle and they are cost effective way to get up to 3hp 3 phase from single phase. I'd have to agree, and wish I had that big a mill, sniff... 15 HP is gonna be a little large for yer mini mill. Just sayin'... ;-) Mark Yep. But I've been drooling over bigger stuff. ;-) I hear ya. Ever since Stuart and Sam started posting videos of their little machines, I've been sportin' a... Well, you know - I wanna bigger machine! Mark -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
No one said you have to turn it on once it is built. John gene heskett wrote: On Monday, April 04, 2011 05:42:05 AM Mark Wendt did opine: On 04/03/2011 05:29 PM, gene heskett wrote: On my BP Series 1 I use an Automation Direct GS2 VFD as it is only 1.5hp for the spindle and they are cost effective way to get up to 3hp 3 phase from single phase. I'd have to agree, and wish I had that big a mill, sniff... 15 HP is gonna be a little large for yer mini mill. Just sayin'... ;-) Mark Yep. But I've been drooling over bigger stuff. ;-) -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Monday, April 04, 2011 10:00:16 AM John Thornton did opine: No one said you have to turn it on once it is built. John True, but short of more buildings, anything else I get will need a place in out of the weather. This postage stamp, trapezoidal shaped lot has 4 outbuildings on it now. It seems like stuff I buy, is here forever. I have had some tools sitting under a tarp in the driveway with 4 Sale signs on them for over a year, no nibbles. Examples: A 12 Craftsman tilting head bandsaw I use for a power hacksaw occasionally, runs well, with over a dozen new and used blades, $200 A 6 Dewalt VS benchtop jointer on a stand w/2 sets new blades, $240new, $60. The VS died and is bypassed. A Craftsman dovetail jig, $80new, $20, no bit. A 10 BD/Dewalt radial arm saw with oversized table, works well, $100 The latter is under foot in the shop building. Listed on the local radio station swap shop program for several months last summer, not even a phone call. Yard sale signs posted most of last summer. Not even a motorized gawker. Which amazes me, this is yard sales by the dozens all summer country. -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html The grass is always greener on the other side of your sunglasses. -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
John, I think it is finally done... sorry for the delay. http://gnipsel.com/shop/rpc/rpc.xhtml John John Crane wrote: John, Thanks for the update. JRC On Sun, Mar 27, 2011 at 6:02 AM, John Thorntonbjt...@gmail.com wrote: I can't find my drawings atm, so I'm recreating them from scratch and will post them as soon as done. Just wanted to let you know I did not forget although sometimes I do. John John Crane wrote: Thanks, John R. Crane On Mon, Mar 21, 2011 at 7:27 AM, John Thorntonbjt...@gmail.com wrote: John, I'll dig out my schematic and make sure it is up to date and figure a way to post it to the list. John John Crane wrote: John, I would like to know more about the way you have engineered your phase converters. I am in the process of adding this capability in my shop. Thanks, John R. Crane On Thu, Mar 17, 2011 at 5:53 AM, John Thorntonbjt...@gmail.com wrote: I have three rotary phase converters. The are all using a potential relay for the start caps and a relay that pulls in the mains. So I don't have to hold the push button and if the power drops out for a few seconds the phase converter does not try and restart without the start caps. I've not had the fun of blowing anything up when building them. They are all balanced phase to phase within a couple of volts. However phase to phase the run caps are very different in order to get the voltage phase to phase to balance. I can post some details if anyone is interested... John Dave wrote: Back when I put my 10 hp phase converter together, I found some charts on the web someplace about suggested capacitor sizing. I found a cheap supply of capacitors at Mendelson's in Dayton, Ohio and bought a small box of them. I ended up using I believe, 4 - 330 uf 330 volt units as starting caps and 4- 135 uf run caps.I use a push button to start the motor and as long as I hold the button down the starting caps are wired into the circuit. When the motor spins up I release the button. I tried to use a voltage sensitive relay, like the ones used on refrigeration systems and AC systems, but it was not reliable probably due to the high current from the large number of caps. There is also a motor contactor that seals itself in via the button push. That way if the line power drops, the contactor drops out and the converter idler motor and he attached slave motors are powered down. The math relating to how this works gets even more complicated when you consider the effects of hooking a 3 phase motor that you are going to start (a slave motor) across the the idling phase converter motor. For a brief period of time, the idler motor becomes a generator. The rotor slows slightly and the energy in the rotor pumps power into the three phases and spins up the slaved motor.It works very well. During experimentation, it is very obvious when more starting capacitors are required as the motor will simply not spin up. Adding more run caps helps balance the phases but they never really fully balance. Safety glasses are very good idea when experimenting.Starting caps go off like firecrackers if you overstress them.They are only designed to be switched in for a few seconds. A source of cheap starting caps is a really good idea if you want to do some phase converter experimentation. I blew up several of them. Dave On 3/14/2011 9:01 PM, Jon Elson wrote: On 14 March 2011 10:50, John Thorntonbjt...@gmail.com wrote: Is it not amazing that the hillbillies from backwoods Missouri with a 3rd grade education can make a rotary phase converter without all the math... Of course! The trick is the windings in the motor do all the math for you, all you need to do is hook up the wires. Jon -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Sun, 2011-04-03 at 10:52 -0400, gene heskett wrote: ... snip I would have a hard time justifying an idling current draw of 35 amps a leg from the 240 to run a 3 horse motor on the machine. This links covers a remote start setup: http://homemetalshopclub.org/projects/phconv/phconv.html This one is new to me: http://hmin.tripod.com/als/andysm/pages/3phase02.html looks similar to John's schematic. I used this link for mine: http://www.metalwebnews.com/howto/ph-conv/ph-conv.html It seems that if I were clever enough, there might be a way to have a low voltage on the converter output that could sense when a machine is turned on, then start the converter, switch in the high voltage, then shut down when no load is sensed. My converter is close to the machine I use it with, so I just turn it on and off as needed. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
I actually have a 24vdc control on the lathe that starts/stops the phase converter right from the lathe front panel. John Kirk Wallace wrote: On Sun, 2011-04-03 at 10:52 -0400, gene heskett wrote: ... snip I would have a hard time justifying an idling current draw of 35 amps a leg from the 240 to run a 3 horse motor on the machine. This links covers a remote start setup: http://homemetalshopclub.org/projects/phconv/phconv.html This one is new to me: http://hmin.tripod.com/als/andysm/pages/3phase02.html looks similar to John's schematic. I used this link for mine: http://www.metalwebnews.com/howto/ph-conv/ph-conv.html It seems that if I were clever enough, there might be a way to have a low voltage on the converter output that could sense when a machine is turned on, then start the converter, switch in the high voltage, then shut down when no load is sensed. My converter is close to the machine I use it with, so I just turn it on and off as needed. -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Sunday, April 03, 2011 04:58:59 PM Dave did opine: It's won't draw anything close to 35 amps and a lot of the currrent it draws will be reactive power (KVARS) which your power meter does not sense (at least it should not). 15 hp is pretty big though, but if the price is right, I'd try it out. The downside is that you will need a lot of caps to spin that baby up. :-) Well, its a spare for the GE TF3a transmitters heat exchanger, shut down 2 years ago now. There is also a couple of spares for the water pump, which are 10's IIRC. And I am good at twisting arms. ;-) Dave On 4/3/2011 10:52 AM, gene heskett wrote: On Sunday, April 03, 2011 10:46:26 AM John Thornton did opine: John, I think it is finally done... sorry for the delay. http://gnipsel.com/shop/rpc/rpc.xhtml John How efficient would you say this is John? I can lay my hands on a 15 hp 3 phase motor for the base iron. And how big a 3 phase motor could be operated from it? I would have a hard time justifying an idling current draw of 35 amps a leg from the 240 to run a 3 horse motor on the machine. -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html The only thing worse than X Windows: (X Windows) - X -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Sunday, April 03, 2011 05:15:32 PM Kirk Wallace did opine: On Sun, 2011-04-03 at 10:52 -0400, gene heskett wrote: ... snip I would have a hard time justifying an idling current draw of 35 amps a leg from the 240 to run a 3 horse motor on the machine. This links covers a remote start setup: http://homemetalshopclub.org/projects/phconv/phconv.html This one is new to me: http://hmin.tripod.com/als/andysm/pages/3phase02.html looks similar to John's schematic. I used this link for mine: http://www.metalwebnews.com/howto/ph-conv/ph-conv.html It seems that if I were clever enough, there might be a way to have a low voltage on the converter output that could sense when a machine is turned on, then start the converter, switch in the high voltage, then shut down when no load is sensed. My converter is close to the machine I use it with, so I just turn it on and off as needed. I'm sure such a gizmo could be designed. The problem is in protecting the sensor from the 30x higher operating voltage. Not to mention that what I could come up with in just a few seconds thought, is probably going to waste at least 5 watts on a 24/7 basis, not a good idea in some locales. -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html Our reruns are better than theirs. -- Nick at Nite -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Sunday, April 03, 2011 05:22:28 PM John Thornton did opine: I run my lathe and mill from it. The lathe is about 7.5hp spindle and the mill is about 7.5hp spindle. And of course it is so convenient I just turn it on when needed and off when not. My EMC machines the computer is on 120vac so I only need the phase converter on when machining. I just checked and the single phase side draws 9 amps when idling and 9.5 with the lathe spindle spinning with no load at 2k. If using an 'AmProbe' like device to measure that, I suspect some reactive power is registering to it, that likely is not registering at the power meter itself. But thats more of a common sense feeling than anything else since it isn't terribly convenient to clock the meters disk and translate that to KWH. It could be done I guess, given a big enough curiosity bump. I'd say it is more efficient than paying the local coop to run 3 phase a few miles back into the woods to me from the highway. Chuckle, for the first 30 years anyway. :-) By then you'll probably have solar and wind and be off the grid because its cheaper than petrol power. On my BP Series 1 I use an Automation Direct GS2 VFD as it is only 1.5hp for the spindle and they are cost effective way to get up to 3hp 3 phase from single phase. I'd have to agree, and wish I had that big a mill, sniff... John gene heskett wrote: On Sunday, April 03, 2011 10:46:26 AM John Thornton did opine: John, I think it is finally done... sorry for the delay. http://gnipsel.com/shop/rpc/rpc.xhtml John How efficient would you say this is John? I can lay my hands on a 15 hp 3 phase motor for the base iron. And how big a 3 phase motor could be operated from it? I would have a hard time justifying an idling current draw of 35 amps a leg from the 240 to run a 3 horse motor on the machine. -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html A long-forgotten loved one will appear soon. Buy the negatives at any price. -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
Right, Amprobes can only measure absolute current. Theorectically a load could draw 10 amps at 230 volts and it would not spin your power meter at all if it had a power factor of zero. But that is pretty much impossible. If the power factor was 50% then the total watts being consumed and registered on you meter would be 10 amps x 230 volts x .5 (50% power factor). Dave On 4/3/2011 5:29 PM, gene heskett wrote: On Sunday, April 03, 2011 05:22:28 PM John Thornton did opine: I run my lathe and mill from it. The lathe is about 7.5hp spindle and the mill is about 7.5hp spindle. And of course it is so convenient I just turn it on when needed and off when not. My EMC machines the computer is on 120vac so I only need the phase converter on when machining. I just checked and the single phase side draws 9 amps when idling and 9.5 with the lathe spindle spinning with no load at 2k. If using an 'AmProbe' like device to measure that, I suspect some reactive power is registering to it, that likely is not registering at the power meter itself. But thats more of a common sense feeling than anything else since it isn't terribly convenient to clock the meters disk and translate that to KWH. It could be done I guess, given a big enough curiosity bump. I'd say it is more efficient than paying the local coop to run 3 phase a few miles back into the woods to me from the highway. Chuckle, for the first 30 years anyway. :-) By then you'll probably have solar and wind and be off the grid because its cheaper than petrol power. On my BP Series 1 I use an Automation Direct GS2 VFD as it is only 1.5hp for the spindle and they are cost effective way to get up to 3hp 3 phase from single phase. I'd have to agree, and wish I had that big a mill, sniff... John gene heskett wrote: On Sunday, April 03, 2011 10:46:26 AM John Thornton did opine: John, I think it is finally done... sorry for the delay. http://gnipsel.com/shop/rpc/rpc.xhtml John How efficient would you say this is John? I can lay my hands on a 15 hp 3 phase motor for the base iron. And how big a 3 phase motor could be operated from it? I would have a hard time justifying an idling current draw of 35 amps a leg from the 240 to run a 3 horse motor on the machine. -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
I can't find my drawings atm, so I'm recreating them from scratch and will post them as soon as done. Just wanted to let you know I did not forget although sometimes I do. John John Crane wrote: Thanks, John R. Crane On Mon, Mar 21, 2011 at 7:27 AM, John Thorntonbjt...@gmail.com wrote: John, I'll dig out my schematic and make sure it is up to date and figure a way to post it to the list. John John Crane wrote: John, I would like to know more about the way you have engineered your phase converters. I am in the process of adding this capability in my shop. Thanks, John R. Crane On Thu, Mar 17, 2011 at 5:53 AM, John Thorntonbjt...@gmail.com wrote: I have three rotary phase converters. The are all using a potential relay for the start caps and a relay that pulls in the mains. So I don't have to hold the push button and if the power drops out for a few seconds the phase converter does not try and restart without the start caps. I've not had the fun of blowing anything up when building them. They are all balanced phase to phase within a couple of volts. However phase to phase the run caps are very different in order to get the voltage phase to phase to balance. I can post some details if anyone is interested... John Dave wrote: Back when I put my 10 hp phase converter together, I found some charts on the web someplace about suggested capacitor sizing. I found a cheap supply of capacitors at Mendelson's in Dayton, Ohio and bought a small box of them. I ended up using I believe, 4 - 330 uf 330 volt units as starting caps and 4- 135 uf run caps.I use a push button to start the motor and as long as I hold the button down the starting caps are wired into the circuit. When the motor spins up I release the button. I tried to use a voltage sensitive relay, like the ones used on refrigeration systems and AC systems, but it was not reliable probably due to the high current from the large number of caps. There is also a motor contactor that seals itself in via the button push. That way if the line power drops, the contactor drops out and the converter idler motor and he attached slave motors are powered down. The math relating to how this works gets even more complicated when you consider the effects of hooking a 3 phase motor that you are going to start (a slave motor) across the the idling phase converter motor. For a brief period of time, the idler motor becomes a generator. The rotor slows slightly and the energy in the rotor pumps power into the three phases and spins up the slaved motor.It works very well. During experimentation, it is very obvious when more starting capacitors are required as the motor will simply not spin up. Adding more run caps helps balance the phases but they never really fully balance. Safety glasses are very good idea when experimenting.Starting caps go off like firecrackers if you overstress them.They are only designed to be switched in for a few seconds. A source of cheap starting caps is a really good idea if you want to do some phase converter experimentation. I blew up several of them. Dave On 3/14/2011 9:01 PM, Jon Elson wrote: On 14 March 2011 10:50, John Thorntonbjt...@gmail.com wrote: Is it not amazing that the hillbillies from backwoods Missouri with a 3rd grade education can make a rotary phase converter without all the math... Of course! The trick is the windings in the motor do all the math for you, all you need to do is hook up the wires. Jon -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization -
Re: [Emc-users] Single to Three Phase Rotary Converters
John, Thanks for the update. JRC On Sun, Mar 27, 2011 at 6:02 AM, John Thornton bjt...@gmail.com wrote: I can't find my drawings atm, so I'm recreating them from scratch and will post them as soon as done. Just wanted to let you know I did not forget although sometimes I do. John John Crane wrote: Thanks, John R. Crane On Mon, Mar 21, 2011 at 7:27 AM, John Thorntonbjt...@gmail.com wrote: John, I'll dig out my schematic and make sure it is up to date and figure a way to post it to the list. John John Crane wrote: John, I would like to know more about the way you have engineered your phase converters. I am in the process of adding this capability in my shop. Thanks, John R. Crane On Thu, Mar 17, 2011 at 5:53 AM, John Thorntonbjt...@gmail.com wrote: I have three rotary phase converters. The are all using a potential relay for the start caps and a relay that pulls in the mains. So I don't have to hold the push button and if the power drops out for a few seconds the phase converter does not try and restart without the start caps. I've not had the fun of blowing anything up when building them. They are all balanced phase to phase within a couple of volts. However phase to phase the run caps are very different in order to get the voltage phase to phase to balance. I can post some details if anyone is interested... John Dave wrote: Back when I put my 10 hp phase converter together, I found some charts on the web someplace about suggested capacitor sizing. I found a cheap supply of capacitors at Mendelson's in Dayton, Ohio and bought a small box of them. I ended up using I believe, 4 - 330 uf 330 volt units as starting caps and 4- 135 uf run caps.I use a push button to start the motor and as long as I hold the button down the starting caps are wired into the circuit. When the motor spins up I release the button. I tried to use a voltage sensitive relay, like the ones used on refrigeration systems and AC systems, but it was not reliable probably due to the high current from the large number of caps. There is also a motor contactor that seals itself in via the button push. That way if the line power drops, the contactor drops out and the converter idler motor and he attached slave motors are powered down. The math relating to how this works gets even more complicated when you consider the effects of hooking a 3 phase motor that you are going to start (a slave motor) across the the idling phase converter motor. For a brief period of time, the idler motor becomes a generator. The rotor slows slightly and the energy in the rotor pumps power into the three phases and spins up the slaved motor.It works very well. During experimentation, it is very obvious when more starting capacitors are required as the motor will simply not spin up. Adding more run caps helps balance the phases but they never really fully balance. Safety glasses are very good idea when experimenting.Starting caps go off like firecrackers if you overstress them.They are only designed to be switched in for a few seconds. A source of cheap starting caps is a really good idea if you want to do some phase converter experimentation. I blew up several of them. Dave On 3/14/2011 9:01 PM, Jon Elson wrote: On 14 March 2011 10:50, John Thorntonbjt...@gmail.com wrote: Is it not amazing that the hillbillies from backwoods Missouri with a 3rd grade education can make a rotary phase converter without all the math... Of course! The trick is the windings in the motor do all the math for you, all you need to do is hook up the wires. Jon -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future.
Re: [Emc-users] Single to Three Phase Rotary Converters
Thanks, John R. Crane On Mon, Mar 21, 2011 at 7:27 AM, John Thornton bjt...@gmail.com wrote: John, I'll dig out my schematic and make sure it is up to date and figure a way to post it to the list. John John Crane wrote: John, I would like to know more about the way you have engineered your phase converters. I am in the process of adding this capability in my shop. Thanks, John R. Crane On Thu, Mar 17, 2011 at 5:53 AM, John Thorntonbjt...@gmail.com wrote: I have three rotary phase converters. The are all using a potential relay for the start caps and a relay that pulls in the mains. So I don't have to hold the push button and if the power drops out for a few seconds the phase converter does not try and restart without the start caps. I've not had the fun of blowing anything up when building them. They are all balanced phase to phase within a couple of volts. However phase to phase the run caps are very different in order to get the voltage phase to phase to balance. I can post some details if anyone is interested... John Dave wrote: Back when I put my 10 hp phase converter together, I found some charts on the web someplace about suggested capacitor sizing. I found a cheap supply of capacitors at Mendelson's in Dayton, Ohio and bought a small box of them. I ended up using I believe, 4 - 330 uf 330 volt units as starting caps and 4- 135 uf run caps.I use a push button to start the motor and as long as I hold the button down the starting caps are wired into the circuit. When the motor spins up I release the button. I tried to use a voltage sensitive relay, like the ones used on refrigeration systems and AC systems, but it was not reliable probably due to the high current from the large number of caps. There is also a motor contactor that seals itself in via the button push. That way if the line power drops, the contactor drops out and the converter idler motor and he attached slave motors are powered down. The math relating to how this works gets even more complicated when you consider the effects of hooking a 3 phase motor that you are going to start (a slave motor) across the the idling phase converter motor. For a brief period of time, the idler motor becomes a generator. The rotor slows slightly and the energy in the rotor pumps power into the three phases and spins up the slaved motor.It works very well. During experimentation, it is very obvious when more starting capacitors are required as the motor will simply not spin up. Adding more run caps helps balance the phases but they never really fully balance. Safety glasses are very good idea when experimenting.Starting caps go off like firecrackers if you overstress them.They are only designed to be switched in for a few seconds. A source of cheap starting caps is a really good idea if you want to do some phase converter experimentation. I blew up several of them. Dave On 3/14/2011 9:01 PM, Jon Elson wrote: On 14 March 2011 10:50, John Thorntonbjt...@gmail.com wrote: Is it not amazing that the hillbillies from backwoods Missouri with a 3rd grade education can make a rotary phase converter without all the math... Of course! The trick is the windings in the motor do all the math for you, all you need to do is hook up the wires. Jon -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the
Re: [Emc-users] Single to Three Phase Rotary Converters
John, I'll dig out my schematic and make sure it is up to date and figure a way to post it to the list. John John Crane wrote: John, I would like to know more about the way you have engineered your phase converters. I am in the process of adding this capability in my shop. Thanks, John R. Crane On Thu, Mar 17, 2011 at 5:53 AM, John Thorntonbjt...@gmail.com wrote: I have three rotary phase converters. The are all using a potential relay for the start caps and a relay that pulls in the mains. So I don't have to hold the push button and if the power drops out for a few seconds the phase converter does not try and restart without the start caps. I've not had the fun of blowing anything up when building them. They are all balanced phase to phase within a couple of volts. However phase to phase the run caps are very different in order to get the voltage phase to phase to balance. I can post some details if anyone is interested... John Dave wrote: Back when I put my 10 hp phase converter together, I found some charts on the web someplace about suggested capacitor sizing. I found a cheap supply of capacitors at Mendelson's in Dayton, Ohio and bought a small box of them. I ended up using I believe, 4 - 330 uf 330 volt units as starting caps and 4- 135 uf run caps.I use a push button to start the motor and as long as I hold the button down the starting caps are wired into the circuit. When the motor spins up I release the button. I tried to use a voltage sensitive relay, like the ones used on refrigeration systems and AC systems, but it was not reliable probably due to the high current from the large number of caps. There is also a motor contactor that seals itself in via the button push. That way if the line power drops, the contactor drops out and the converter idler motor and he attached slave motors are powered down. The math relating to how this works gets even more complicated when you consider the effects of hooking a 3 phase motor that you are going to start (a slave motor) across the the idling phase converter motor. For a brief period of time, the idler motor becomes a generator. The rotor slows slightly and the energy in the rotor pumps power into the three phases and spins up the slaved motor.It works very well. During experimentation, it is very obvious when more starting capacitors are required as the motor will simply not spin up. Adding more run caps helps balance the phases but they never really fully balance. Safety glasses are very good idea when experimenting.Starting caps go off like firecrackers if you overstress them.They are only designed to be switched in for a few seconds. A source of cheap starting caps is a really good idea if you want to do some phase converter experimentation. I blew up several of them. Dave On 3/14/2011 9:01 PM, Jon Elson wrote: On 14 March 2011 10:50, John Thorntonbjt...@gmail.com wrote: Is it not amazing that the hillbillies from backwoods Missouri with a 3rd grade education can make a rotary phase converter without all the math... Of course! The trick is the windings in the motor do all the math for you, all you need to do is hook up the wires. Jon -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list
Re: [Emc-users] Single to Three Phase Rotary Converters
John, I would like to know more about the way you have engineered your phase converters. I am in the process of adding this capability in my shop. Thanks, John R. Crane On Thu, Mar 17, 2011 at 5:53 AM, John Thornton bjt...@gmail.com wrote: I have three rotary phase converters. The are all using a potential relay for the start caps and a relay that pulls in the mains. So I don't have to hold the push button and if the power drops out for a few seconds the phase converter does not try and restart without the start caps. I've not had the fun of blowing anything up when building them. They are all balanced phase to phase within a couple of volts. However phase to phase the run caps are very different in order to get the voltage phase to phase to balance. I can post some details if anyone is interested... John Dave wrote: Back when I put my 10 hp phase converter together, I found some charts on the web someplace about suggested capacitor sizing. I found a cheap supply of capacitors at Mendelson's in Dayton, Ohio and bought a small box of them. I ended up using I believe, 4 - 330 uf 330 volt units as starting caps and 4- 135 uf run caps.I use a push button to start the motor and as long as I hold the button down the starting caps are wired into the circuit. When the motor spins up I release the button. I tried to use a voltage sensitive relay, like the ones used on refrigeration systems and AC systems, but it was not reliable probably due to the high current from the large number of caps. There is also a motor contactor that seals itself in via the button push. That way if the line power drops, the contactor drops out and the converter idler motor and he attached slave motors are powered down. The math relating to how this works gets even more complicated when you consider the effects of hooking a 3 phase motor that you are going to start (a slave motor) across the the idling phase converter motor. For a brief period of time, the idler motor becomes a generator. The rotor slows slightly and the energy in the rotor pumps power into the three phases and spins up the slaved motor.It works very well. During experimentation, it is very obvious when more starting capacitors are required as the motor will simply not spin up. Adding more run caps helps balance the phases but they never really fully balance. Safety glasses are very good idea when experimenting.Starting caps go off like firecrackers if you overstress them.They are only designed to be switched in for a few seconds. A source of cheap starting caps is a really good idea if you want to do some phase converter experimentation. I blew up several of them. Dave On 3/14/2011 9:01 PM, Jon Elson wrote: On 14 March 2011 10:50, John Thorntonbjt...@gmail.comwrote: Is it not amazing that the hillbillies from backwoods Missouri with a 3rd grade education can make a rotary phase converter without all the math... Of course! The trick is the windings in the motor do all the math for you, all you need to do is hook up the wires. Jon -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Sun, 2011-03-20 at 13:35 -0500, John Crane wrote: John, I would like to know more about the way you have engineered your phase converters. I am in the process of adding this capability in my shop. Thanks, John R. Crane In case it might help, this is the design I used: http://www.metalwebnews.com/howto/ph-conv/ph-conv.html -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
I have three rotary phase converters. The are all using a potential relay for the start caps and a relay that pulls in the mains. So I don't have to hold the push button and if the power drops out for a few seconds the phase converter does not try and restart without the start caps. I've not had the fun of blowing anything up when building them. They are all balanced phase to phase within a couple of volts. However phase to phase the run caps are very different in order to get the voltage phase to phase to balance. I can post some details if anyone is interested... John Dave wrote: Back when I put my 10 hp phase converter together, I found some charts on the web someplace about suggested capacitor sizing. I found a cheap supply of capacitors at Mendelson's in Dayton, Ohio and bought a small box of them. I ended up using I believe, 4 - 330 uf 330 volt units as starting caps and 4- 135 uf run caps.I use a push button to start the motor and as long as I hold the button down the starting caps are wired into the circuit. When the motor spins up I release the button. I tried to use a voltage sensitive relay, like the ones used on refrigeration systems and AC systems, but it was not reliable probably due to the high current from the large number of caps. There is also a motor contactor that seals itself in via the button push. That way if the line power drops, the contactor drops out and the converter idler motor and he attached slave motors are powered down. The math relating to how this works gets even more complicated when you consider the effects of hooking a 3 phase motor that you are going to start (a slave motor) across the the idling phase converter motor. For a brief period of time, the idler motor becomes a generator. The rotor slows slightly and the energy in the rotor pumps power into the three phases and spins up the slaved motor.It works very well. During experimentation, it is very obvious when more starting capacitors are required as the motor will simply not spin up. Adding more run caps helps balance the phases but they never really fully balance. Safety glasses are very good idea when experimenting.Starting caps go off like firecrackers if you overstress them.They are only designed to be switched in for a few seconds. A source of cheap starting caps is a really good idea if you want to do some phase converter experimentation. I blew up several of them. Dave On 3/14/2011 9:01 PM, Jon Elson wrote: On 14 March 2011 10:50, John Thorntonbjt...@gmail.comwrote: Is it not amazing that the hillbillies from backwoods Missouri with a 3rd grade education can make a rotary phase converter without all the math... Of course! The trick is the windings in the motor do all the math for you, all you need to do is hook up the wires. Jon -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
Back when I put my 10 hp phase converter together, I found some charts on the web someplace about suggested capacitor sizing. I found a cheap supply of capacitors at Mendelson's in Dayton, Ohio and bought a small box of them. I ended up using I believe, 4 - 330 uf 330 volt units as starting caps and 4- 135 uf run caps.I use a push button to start the motor and as long as I hold the button down the starting caps are wired into the circuit. When the motor spins up I release the button. I tried to use a voltage sensitive relay, like the ones used on refrigeration systems and AC systems, but it was not reliable probably due to the high current from the large number of caps. There is also a motor contactor that seals itself in via the button push. That way if the line power drops, the contactor drops out and the converter idler motor and he attached slave motors are powered down. The math relating to how this works gets even more complicated when you consider the effects of hooking a 3 phase motor that you are going to start (a slave motor) across the the idling phase converter motor. For a brief period of time, the idler motor becomes a generator. The rotor slows slightly and the energy in the rotor pumps power into the three phases and spins up the slaved motor.It works very well. During experimentation, it is very obvious when more starting capacitors are required as the motor will simply not spin up. Adding more run caps helps balance the phases but they never really fully balance. Safety glasses are very good idea when experimenting.Starting caps go off like firecrackers if you overstress them.They are only designed to be switched in for a few seconds. A source of cheap starting caps is a really good idea if you want to do some phase converter experimentation. I blew up several of them. Dave On 3/14/2011 9:01 PM, Jon Elson wrote: On 14 March 2011 10:50, John Thorntonbjt...@gmail.com wrote: Is it not amazing that the hillbillies from backwoods Missouri with a 3rd grade education can make a rotary phase converter without all the math... Of course! The trick is the windings in the motor do all the math for you, all you need to do is hook up the wires. Jon -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Mon, 2011-03-14 at 11:00 +, andy pugh wrote: which caused some worrying sizzling noises. Obviously, your radio isn't turned up nearly loud enough... (Which helps with car repairs, too.) -- Ed http://softsolder.com -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On 14 March 2011 15:30, gene heskett ghesk...@wdtv.com wrote: If I read it right, it is being said that perhaps a capacitor of the correct value to create a usable phase lead, from L1 or L2 to L3, will start a 3 phase motor on single phase power, direction of the rotation dependent on which 2 the capacitor is connected to. Yes, in fact this is how my coolant pump is wired. You don't get the same power output, and the motor needs to have an external star point so that it can be wired for the lower voltage, but it works fine. In fact, many of the cheaper single phase motors are exactly that, a three-phase motor and permanently connected capacitor, with no centrifugal switch. I don't know if it is still the case, but the single-phase motor we bought from Machine Mart was exactly this, and had far too little starting torque for the vehicle lift we wanted to run. http://www.machinemart.co.uk/shop/range/details/230v-110v-single-phase-motors/path/single-phase-electric-motors -- atp Torque wrenches are for the obedience of fools and the guidance of wise men -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Mon, 2011-03-14 at 15:41 +, andy pugh wrote: On 14 March 2011 15:30, gene heskett ghesk...@wdtv.com wrote: If I read it right, it is being said that perhaps a capacitor of the correct value to create a usable phase lead, from L1 or L2 to L3, will start a 3 phase motor on single phase power, direction of the rotation dependent on which 2 the capacitor is connected to. Yes, in fact this is how my coolant pump is wired. You don't get the same power output, and the motor needs to have an external star point so that it can be wired for the lower voltage, but it works fine. In fact, many of the cheaper single phase motors are exactly that, a three-phase motor and permanently connected capacitor, with no centrifugal switch. I don't know if it is still the case, but the single-phase motor we bought from Machine Mart was exactly this, and had far too little starting torque for the vehicle lift we wanted to run. http://www.machinemart.co.uk/shop/range/details/230v-110v-single-phase-motors/path/single-phase-electric-motors My home built 5 Hp converter uses a ~240 uF starting cap and much less than that on the legs. If you really want it right you adjust the caps to get the voltage on the third leg correct. Pretty easy even without the mathematical analysis. Some things can be done just by trial and error; usually more error than trial. ;-) Copying someone else's example helps a lot, at least to get started. Dave -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
Gentlemen, using a phase pusher capacitor is a cheap and common workaround when a three phase supply isn't available. I have used this with a lathe for some time, since a machine like this doesn't need its full power most of the time and it always starts idling without load. Ordinary three phase current runs 120 + 120 + 120 degrees to make a full revolution. If you have only two, this makes it 180 + 180 and won't run because there is no direction information in it. A capacitor connected to one leg of the two-phase system produces a 90 degree phase shift relative to this lead. Using this as a mock three phase system, you will have 180 + 90 +90 degrees for a revolution including a direction information, depending to which leg you connected the capacitor. The distribution is uneven which is the reason for reduced power, but better than nothing. Don't confuse this with a starter capacitor used to supply a direction information to a generic two phase motor! Those are for short time use with small motors only and blow their tops when used continously (because of faulty starter relay or so). Of course, the size of the capacitor depends on the amount of current it has to supply to the third leg. Having learned from practice, I used at least 70 microfarads per kW to achieve about half the power the motor can deliver on a real three phase system. More capacity doesn't contribute much. The capacitors need to have a voltage rating of mains voltage times sqrt of 2. The cheapest way to get them ( I was a student then) was cannibalizing the current compensation capacitors from old flourescent lamps at the junk yard. I needed about a dozen of them, but at zero expense. Watch for belly shaped tops, there is plenty of stinking smoke compressed by the factory in these aluminum cans! Perter Blodow andy pugh schrieb: On 14 March 2011 15:30, gene heskett ghesk...@wdtv.com wrote: If I read it right, it is being said that perhaps a capacitor of the correct value to create a usable phase lead, from L1 or L2 to L3, will start a 3 phase motor on single phase power, direction of the rotation dependent on which 2 the capacitor is connected to. Yes, in fact this is how my coolant pump is wired. You don't get the same power output, and the motor needs to have an external star point so that it can be wired for the lower voltage, but it works fine. In fact, many of the cheaper single phase motors are exactly that, a three-phase motor and permanently connected capacitor, with no centrifugal switch. I don't know if it is still the case, but the single-phase motor we bought from Machine Mart was exactly this, and had far too little starting torque for the vehicle lift we wanted to run. http://www.machinemart.co.uk/shop/range/details/230v-110v-single-phase-motors/path/single-phase-electric-motors -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Mon, 2011-03-14 at 17:58 +0100, Peter Blodow wrote: ... snip A capacitor connected to one leg of the two-phase system produces a 90 degree phase shift relative to this lead. Using this as a mock three phase system, you will have 180 + 90 +90 degrees for a revolution including a direction information, depending to which leg you connected the capacitor. The distribution is uneven which is the reason for reduced power, but better than nothing. Don't confuse this with a starter capacitor used to supply a direction information to a generic two phase motor! Those are for short time use with small motors only and blow their tops when used continously (because of faulty starter relay or so). In case my attachment doesn't go through, here is my graphical study of a rotary three phase converter: http://www.wallacecompany.com/machine_shop/EMC2/three_phase_converter-1a.png The 180 degree voltage phase shift is only an issue if neutral is used, but it is not. I think the decrease in efficiency is due to using one phase to try to generate two more and the currents are much higher than normal. (Viva VFD's) -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On 14 March 2011 19:42, Kirk Wallace kwall...@wallacecompany.com wrote: In case my attachment doesn't go through, here is my graphical study of a rotary three phase converter: http://www.wallacecompany.com/machine_shop/EMC2/three_phase_converter-1a.png You have 2-phase power? In the UK we get one phase and line neutral. (Not that that actually matters at all) -- atp Torque wrenches are for the obedience of fools and the guidance of wise men -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
Kirk, I believe that now you got everything completely right. i On Mon, Mar 14, 2011 at 2:42 PM, Kirk Wallace kwall...@wallacecompany.comwrote: On Mon, 2011-03-14 at 17:58 +0100, Peter Blodow wrote: ... snip A capacitor connected to one leg of the two-phase system produces a 90 degree phase shift relative to this lead. Using this as a mock three phase system, you will have 180 + 90 +90 degrees for a revolution including a direction information, depending to which leg you connected the capacitor. The distribution is uneven which is the reason for reduced power, but better than nothing. Don't confuse this with a starter capacitor used to supply a direction information to a generic two phase motor! Those are for short time use with small motors only and blow their tops when used continously (because of faulty starter relay or so). In case my attachment doesn't go through, here is my graphical study of a rotary three phase converter: http://www.wallacecompany.com/machine_shop/EMC2/three_phase_converter-1a.png The 180 degree voltage phase shift is only an issue if neutral is used, but it is not. I think the decrease in efficiency is due to using one phase to try to generate two more and the currents are much higher than normal. (Viva VFD's) -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Mon, 2011-03-14 at 14:54 -0500, Igor Chudov wrote: Kirk, I believe that now you got everything completely right. i Thank you. This is why I value when people let me know when I may be wrong. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
Hello Andy, it's just the same here, if you separate the usual three phase supply into three separate 230 V-systems, each defined to ground. I was talking about a, say, small household, where only one of these phases is available. Other households in the same building may have others of the three phases. We used to call them R, S and T. Lacking the other p´hases, you can make a third phase for your household by means of a phase shifting capacitor and make a mock three phase system with reduced power beause of the unsymmetry. Don't care about the neutral line being grounded. Peter Blodow andy pugh schrieb: On 14 March 2011 19:42, Kirk Wallace kwall...@wallacecompany.com wrote: In case my attachment doesn't go through, here is my graphical study of a rotary three phase converter: http://www.wallacecompany.com/machine_shop/EMC2/three_phase_converter-1a.png You have 2-phase power? In the UK we get one phase and line neutral. (Not that that actually matters at all) -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
Kirk Wallace schrieb: On Mon, 2011-03-14 at 22:55 +0100, Peter Blodow wrote: Kirk, Neutral is not to be considered. You have two wires coming from the supplier. Adding a capacitor makes three of them. The two mains lines are 180 degrees apart by definition. The capacitor makes a third phase 90 degrees between them. Connect your motor, and it will be running, regardless of which line is grounded. Peter Blodow Sort of. Your description above I believe matches my diagram showing the starting mode, or the middle picture: http://www.wallacecompany.com/machine_shop/EMC2/three_phase_converter-1a.png In my original argument, I stated I thought L1 and L2 from the mains are 180 degrees apart, because if you scope L1, you get a sine wave. If you scope L2, you get a sine wave that is shifted 180 degrees from the L1 sine wave. The problem is that the scope uses ground or neutral as the reference for the L1 and L2 voltage. but the neutral is not used in the circuit so the 180 degrees doesn't apply or add to the understanding of how the circuit works. The only thing we know is that there is a single 240 Volt sine wave when L1 is referenced to L2 or vis versa and this single wave is connected across a single phase on the converter motor. Once I drew this single phase wave on the A and B converter motor terminals, everything else flowed from that. The only time 180 degrees came to mind from developing this diagram was in considering the unconnected C terminal relative to A and B. C looks like a transformer center tap relative to A and B, so there should be a sine wave between L1 (A) and and C that is 180 degrees from L2 (B) and C. To me so far, this doesn't add anything to the understanding of the converter. You are considering a two phase system whichis actually a one phase system of, say, 230 volts per phase. In this case, everything is symmetrical, and each wire is 180 degrees apart form the other, regardless of which is grounded. One one them is defined as zero volts, so the other one will be 230 volts (therefore one phase). In a three phase system, three leads are carrying 230 volts per phase also, but considering the delta shape of the connection, beween them there will be a voltage of 230 volts times sqrt of three, approx. 400 volts. Imagine the whole thing as a regular triangle with three equal sides and the center grounded, it is easy to see that you can make three single 230 volts AC circuits referenced to ground or neutral (which will not be delivered by the power supplier in every instance, but defined locally by grounding the center tap of the power line transformer station). This is the basic great idea of three phase supply - transport 75% more energy by use of 50 % more wires, not counting the advantage of a direction of rotation information. In summary, with a usual 230/400 volts three phase system, you can split this into three single phase, 230 volts systems (L1, L2, L3 or R, S, T) referenced to ground (N) or use it as a 400 volts rotary system for motion devices, regardless of ground. In case of unavailability of the two other phases, use a phase shift capacitor to create your own 230 volts rotary system (with power drawbacks), wire your motor in delta 230 volts and run your machines as good as they will run! Peter Blodow My converter does have a pair of running capacitors and sometime I may try to apply the start capacitor logic to these to try to figure out how they work. My guess is that they store energy during the motor period and release it during the generating period of each shaft rotation, but I can't prove it, yet. -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On 14 March 2011 10:50, John Thorntonbjt...@gmail.com wrote: Is it not amazing that the hillbillies from backwoods Missouri with a 3rd grade education can make a rotary phase converter without all the math... Of course! The trick is the windings in the motor do all the math for you, all you need to do is hook up the wires. Jon -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Single to Three Phase Rotary Converters
On Wed, Mar 9, 2011 at 12:35 AM, Kirk Wallace kwall...@wallacecompany.comwrote: Let me try to provide more details on my understanding of the phase timing of DIY converters. Attached is a schematic of a common rotary converter. The source is here: http://www.metalwebnews.com/howto/ph-conv/ph-conv.html http://www.metalwebnews.com/howto/ph-conv/fig1.html I used this to make my converter and is the only design I have some understanding of. As the schematic shows L1 and L2 go straight to the output and are unaffected. Since L1 and L2 are single phase, L1 is a mirror of L2, therefore 180 degrees out of 360 apart. But, but, you are committing a tautology. If you reference L1 to L2 and vice versa, of course L1 is a mirror of L2. In your scheme there is no 'ground' or reference point, so you only have one phase coming in, and the motor generates the second (and third) phase L3, shifted with respect to L1/L2. One way to see it comes from the trigonometric identity holding that sum of three sines shifted by 0, 120 and 240 degrees is zero: sin(x)+sin(x+2*%pi/3)+sin(x+4*%pi/3)=0 Let's say we take some arbitrary reference point, so that L1(t) is the voltage on the first leg. Assume L2(t)-L1(t) = V sin(2 pi f t). If the converter generates L3(t)=L1(t)-V sin(2 pi f t + 2/3 pi), then L1-L3 is V sin(2 pi f t + 2/3 pi), i.e. shifted by 120 degrees, and L3-L2 is -V sin(2 pi f t + 2/3pi) - V sin(2 pi f t) which reduces to V sin(x+4*%pi/3) i.e. the same AC shifted 240 degrees. Note that it doesn't matter what the reference point is, because its potential L1(t) drops out --- all that matters are voltage differences between the legs of the circuit, not the potentials of the legs themselves. -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Single to Three Phase Rotary Converters
Let me try to provide more details on my understanding of the phase timing of DIY converters. Attached is a schematic of a common rotary converter. The source is here: http://www.metalwebnews.com/howto/ph-conv/ph-conv.html http://www.metalwebnews.com/howto/ph-conv/fig1.html I used this to make my converter and is the only design I have some understanding of. As the schematic shows L1 and L2 go straight to the output and are unaffected. Since L1 and L2 are single phase, L1 is a mirror of L2, therefore 180 degrees out of 360 apart. Attached is a diagram showing my understanding of the single phase house connection. A single wire, or single phase, is fed at street level to a pole transformer with the primary terminated to ground. The secondary reduces the voltage to 240V. The center tap goes to ground and the voltage of each leg is 120 volts and one leg appears inverted, in reference to ground, to the other. Back to the converter, L3 is derived from a combination of L1 and L2 and the back EMF from the idler motor. My best guess is that the phase angle is half way at 90 or 270 degrees. But L1 and L2 are still 180. In searching for Scott-T, I found this page: http://cableorganizer.com/articles/three-phase-electric-power.html which states: Some devices are made which create an imitation three-phase from three-wire single phase supplies. This is done by creating a third subphase between the two live conductors, resulting in a phase separation of 180° − 90° = 90°. Many three-phase devices will run on this configuration, but at lower efficiency. Later in the page, it states: Two-phase power may be obtained from a three-phase system using an arrangement of transformers called a Scott-T transformer. I am assuming two phase power is like a quadrature pair of signals. Special-purpose systems may use a two-phase system for control. and not like single or three phase, unless the power company only runs L1h and L2h out to your pole. Also see: http://en.wikipedia.org/wiki/Three-phase_electric_power http://en.wikipedia.org/wiki/Scott-T_transformer I'm not trying to say anybody is wrong, but I haven't seen anything that has convinced me that I am. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA attachment: fig1.gifattachment: mains.png-- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
