Re: [Emc-users] stepper power supply
On Thu, 2011-12-29 at 21:14 -0500, gene heskett wrote: pointers to the articles That was a series on transformers triac triggering, with a resistance soldering setup as the McGuffin. CC doesn't put articles online (if you know where to look, go for April/June/August 2008), but I put up some notes a while ago; start at the first post and rummage through the next few days: http://softsolder.com/2010/09/07/resistance-soldering-gizmo-overview/ The transformer notes, complete with a B-H curve, may be most useful: http://softsolder.com/2010/09/08/resistance-soldering-transformer/ The triac trigger circuitry was *insanely* complex, because I wanted to show what happens during four-quadrant triggering with sub-cycle control. In real life, you'd just fire a triac driver for the entire heating pulse and be done with it. A while back, Eks forced me to take his homebrew water-cooled pulser built around a stack of hockey-puck transistors that he'd been using for EDM. All I need is a bulk supply behind the thing, a bit of Z axis control, and I could sink dies with the best of 'em... [sigh] -- Ed http://softsolder.com -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Friday, December 30, 2011 01:42:36 PM Ed Nisley did opine: On Thu, 2011-12-29 at 21:14 -0500, gene heskett wrote: pointers to the articles That was a series on transformers triac triggering, with a resistance soldering setup as the McGuffin. CC doesn't put articles online (if you know where to look, go for April/June/August 2008), but I put up some notes a while ago; start at the first post and rummage through the next few days: http://softsolder.com/2010/09/07/resistance-soldering-gizmo-overview/ The transformer notes, complete with a B-H curve, may be most useful: http://softsolder.com/2010/09/08/resistance-soldering-transformer/ The triac trigger circuitry was *insanely* complex, because I wanted to show what happens during four-quadrant triggering with sub-cycle control. In real life, you'd just fire a triac driver for the entire heating pulse and be done with it. A while back, Eks forced me to take his homebrew water-cooled pulser built around a stack of hockey-puck transistors that he'd been using for EDM. All I need is a bulk supply behind the thing, a bit of Z axis control, and I could sink dies with the best of 'em... [sigh] Chuckle, thanks for copying the mail Ed. But that last one will need some very good earmuffs, 30db or better if you intend to be in the same building with it. Of course I had a whole 10 circular saw blade on the table, which predictably rang like the bells hell most likely uses for an escape alarm bell. I also was using too big a cap (10 mics, 600 volt, its what was on the shelf for spares for a 55 yo GE transmitter I wasn't being too fussy about whose junkbox shelf I was raiding given that transmitters limited 45 day future in mid-May of 2008) :) 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) My web page: http://coyoteden.dyndns-free.com:85/gene Real programmers don't bring brown-bag lunches. If the vending machine doesn't sell it, they don't eat it. Vending machines don't sell quiche. -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
Ed, do you know how stable the voltage remains across a range of loads from open to dead short? Curbside microwaves and some heavy gauge wire sounds a whole lot cheaper than commercially produced transformers. 1KW at 13.5V +/- 1.5V could come in handy, but not handy enough for my budget to justify a commercially available solution. I also read that transformers are put under more stress when the secondaries are rectified. I'll need to do some more reading on this as well. One last question... any reason this tecnique couldn't be used for higher voltages on the secondaries? Like around 140 to 165V? (Assuming secondary winding's insulation is adequate) I'm thinking that transformer isolation might be safer than running on rectified 110. Thanks for the food for my thoughts Jim Coleman On Dec 30, 2011 1:56 PM, gene heskett ghesk...@wdtv.com wrote: On Friday, December 30, 2011 01:42:36 PM Ed Nisley did opine: On Thu, 2011-12-29 at 21:14 -0500, gene heskett wrote: pointers to the articles That was a series on transformers triac triggering, with a resistance soldering setup as the McGuffin. CC doesn't put articles online (if you know where to look, go for April/June/August 2008), but I put up some notes a while ago; start at the first post and rummage through the next few days: http://softsolder.com/2010/09/07/resistance-soldering-gizmo-overview/ The transformer notes, complete with a B-H curve, may be most useful: http://softsolder.com/2010/09/08/resistance-soldering-transformer/ The triac trigger circuitry was *insanely* complex, because I wanted to show what happens during four-quadrant triggering with sub-cycle control. In real life, you'd just fire a triac driver for the entire heating pulse and be done with it. A while back, Eks forced me to take his homebrew water-cooled pulser built around a stack of hockey-puck transistors that he'd been using for EDM. All I need is a bulk supply behind the thing, a bit of Z axis control, and I could sink dies with the best of 'em... [sigh] Chuckle, thanks for copying the mail Ed. But that last one will need some very good earmuffs, 30db or better if you intend to be in the same building with it. Of course I had a whole 10 circular saw blade on the table, which predictably rang like the bells hell most likely uses for an escape alarm bell. I also was using too big a cap (10 mics, 600 volt, its what was on the shelf for spares for a 55 yo GE transmitter I wasn't being too fussy about whose junkbox shelf I was raiding given that transmitters limited 45 day future in mid-May of 2008) :) 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) My web page: http://coyoteden.dyndns-free.com:85/gene Real programmers don't bring brown-bag lunches. If the vending machine doesn't sell it, they don't eat it. Vending machines don't sell quiche. -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Fri, 2011-12-30 at 16:33 -0500, Jim Coleman wrote: how stable the voltage remains across a range of loads I really didn't measure that, but I think the core losses are just this side of terrible. After all, they used core saturation for output power control, so reducing losses probably wasn't particularly important. Some handwaving: It pushed 280 A into a 14 m-ohm load with 4.1 V at the lugs, which made the winding + terminal resistance 3 to 4 m-ohm. That's higher than I expected for four parallel #10 wires: 1 m-ohm/ft x 4 ft = 4 m-ohm each, so you'd expect 1 m-ohm total. Frankly, my measurement accuracy isn't up to the task and I'm ignoring core losses. Putting three of those #10 wires in series, rather than parallel, would give 15 V with maybe 10 m-ohm. You pull 75 A for 1 kW at 13.5 V, so the voltage would drop a bit under 1 V due to copper resistance. Add or subtract a turn or two for the right answer. It might come heartbreakingly close to working. any reason this technique couldn't be used for higher voltages The original secondary had a bazillion turns of fine wire to stuff what, 4 kV or so into the magnetron. The catch would be winding the heavy wire you need at 1 V/turn: a dozen or so turns would be do-able, but much beyond that won't fit through the core windows. You could, I suppose, delaminate the transformer and start all over again, but that starts to resemble actual work. Also, the recycled Romex wire I used is, , suboptimal in a high-current transformer. I'm not sure you (well, I) could feed enamel (or whatever they use these days) insulation through the core windows without nicking it; the thick plastic insulation on that Romex gave me decent results with crude techniques. But, again, it'd probably come pretty close to working... -- Ed http://softsolder.com -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Thu, 29 Dec 2011, gene heskett wrote: On Thursday, December 29, 2011 09:05:54 AM kqt4a...@gmail.com did opine: Just in case y'all run out of something to ponder I do not have one of those fancy meters Gene mentioned but I do have a Kill-A-Watt 118.7 volts ac 3 motors at rest - 1.15 amps 3 motors running - 1.6 amps 4 motors at rest - 1.43 amps 4 motors running - 1.85 amps This is killing my electric bill :) Richard Love it, Richard. I have been meaning to get me one of those critters myself. Could you elaborate on the size of the motors and the PSU's output voltage? 1 - Probotix 40VDC 10Amp Linear Power Supply, no manual 3 - http://www.probotix.com/index.php?view=productpath=14product_id=51 # 280 Oz In. Hybrid # 1.8 /200 Steps Per Rev. # 3 Amps Current Per Phase (Uni-polar) # 8-wire Uni-polar or Bi-polar # NEMA 23 Frame 1 - Pacific Scientific Powermax II stepper model P21NRXA-LNF-NS-00 http://www.electromate.com/db_support/downloads/Nema23PowermaxII.pdf 200 steps per rev 2.8 amps 8-wire -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Thu, 29 Dec 2011, gene heskett wrote: On Thursday, December 29, 2011 10:08:23 AM kqt4a...@gmail.com did opine: On Thu, 29 Dec 2011, gene heskett wrote: On Thursday, December 29, 2011 09:05:54 AM kqt4a...@gmail.com did opine: Just in case y'all run out of something to ponder I do not have one of those fancy meters Gene mentioned but I do have a Kill-A-Watt 118.7 volts ac 3 motors at rest - 1.15 amps 3 motors running - 1.6 amps 4 motors at rest - 1.43 amps 4 motors running - 1.85 amps This is killing my electric bill :) Richard Love it, Richard. I have been meaning to get me one of those critters myself. Could you elaborate on the size of the motors and the PSU's output voltage? 1 - Probotix 40VDC 10Amp Linear Power Supply, no manual And linear is not as efficient, but far more tolerant of surges. What did they want for it? $85.95 It was an upgrade when I bought a V90 I'm currently running on a 28 volt switcher good for 12.5 amps if actively cooled. 42 volt rated drivers, so I would like to locate a higher voltage (36?)supply. OTOH, I've only $30 from All Electronics in this one, which also has 5 and 12 volt outputs at logic circuit currents. They are live full time but the main output is switchable, medical grade stuffs they claim. 3 - http://www.probotix.com/index.php?view=productpath=14product_id=51 # 280 Oz In. Hybrid # 1.8 /200 Steps Per Rev. # 3 Amps Current Per Phase (Uni-polar) # 8-wire Uni-polar or Bi-polar # NEMA 23 Frame 262's, 4 wire for XYA, 425 on Z, 8 wire used as 4. 1 - Pacific Scientific Powermax II stepper model P21NRXA-LNF-NS-00 http://www.electromate.com/db_support/downloads/Nema23PowermaxII.pdf 200 steps per rev 2.8 amps 8-wire I think the 28 volts is making the MM-542's run warmer, so a 36 would be better. Running at 2.4 amps, could raise that 1 notch I think. 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) My web page: http://coyoteden.dyndns-free.com:85/gene Conquering Russia should be done steppe by steppe. -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Thursday, December 29, 2011 09:13:26 AM Ed Nisley did opine: On Wed, 2011-12-28 at 12:03 -0500, gene heskett wrote: There are hall effect based ammeters A while back, I mooched a Tek Hall-effect current probe from my buddy Eks to take some interesting pix: http://softsolder.com/2011/06/20/stepper-sync-wheel-current-waveform-fir st-light/ http://softsolder.com/2011/06/27/stepper-motor-winding-current-rise-tim e/ The winding current stays within a skosh of the setpoint for each microstep, which the driver determines by applying the sine cosine of the microstep (electrical) angle to the overall peak current setpoint. That may also contribute to the mystical 70% derating factor, because in full-step mode the driver (well, Allegro drivers, anyway) applies 1/sqrt(2) = 0.71 of the peak current setpoint to *each* winding. That keeps the overall motor power dissipation the same, but the total current into both windings is 2*(1/sqrt(2))*peak = 1.4*peak. Perhaps the person who first stated that factor, back in the dim past, forgot about the current in the *other* winding? While I was doing that, I managed to stoke a mechanical resonance that back-drove the winding current something awful: http://softsolder.com/2011/09/12/stepper-dynamometer-mechanical-resonanc e/ Keeps me off the streets at night... [grin] Thanks Ed. As usual, to the point on several subjects. 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) My web page: http://coyoteden.dyndns-free.com:85/gene Ask not for whom the telephone bell tolls... if thou art in the bathtub, it tolls for thee. -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Thursday, December 29, 2011 10:08:23 AM kqt4a...@gmail.com did opine: On Thu, 29 Dec 2011, gene heskett wrote: On Thursday, December 29, 2011 09:05:54 AM kqt4a...@gmail.com did opine: Just in case y'all run out of something to ponder I do not have one of those fancy meters Gene mentioned but I do have a Kill-A-Watt 118.7 volts ac 3 motors at rest - 1.15 amps 3 motors running - 1.6 amps 4 motors at rest - 1.43 amps 4 motors running - 1.85 amps This is killing my electric bill :) Richard Love it, Richard. I have been meaning to get me one of those critters myself. Could you elaborate on the size of the motors and the PSU's output voltage? 1 - Probotix 40VDC 10Amp Linear Power Supply, no manual And linear is not as efficient, but far more tolerant of surges. What did they want for it? I'm currently running on a 28 volt switcher good for 12.5 amps if actively cooled. 42 volt rated drivers, so I would like to locate a higher voltage (36?)supply. OTOH, I've only $30 from All Electronics in this one, which also has 5 and 12 volt outputs at logic circuit currents. They are live full time but the main output is switchable, medical grade stuffs they claim. 3 - http://www.probotix.com/index.php?view=productpath=14product_id=51 # 280 Oz In. Hybrid # 1.8 /200 Steps Per Rev. # 3 Amps Current Per Phase (Uni-polar) # 8-wire Uni-polar or Bi-polar # NEMA 23 Frame 262's, 4 wire for XYA, 425 on Z, 8 wire used as 4. 1 - Pacific Scientific Powermax II stepper model P21NRXA-LNF-NS-00 http://www.electromate.com/db_support/downloads/Nema23PowermaxII.pdf 200 steps per rev 2.8 amps 8-wire I think the 28 volts is making the MM-542's run warmer, so a 36 would be better. Running at 2.4 amps, could raise that 1 notch I think. 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) My web page: http://coyoteden.dyndns-free.com:85/gene Conquering Russia should be done steppe by steppe. -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Thursday, December 29, 2011 01:10:20 PM kqt4a...@gmail.com did opine: On Thu, 29 Dec 2011, gene heskett wrote: On Thursday, December 29, 2011 10:08:23 AM kqt4a...@gmail.com did opine: On Thu, 29 Dec 2011, gene heskett wrote: On Thursday, December 29, 2011 09:05:54 AM kqt4a...@gmail.com did opine: Just in case y'all run out of something to ponder I do not have one of those fancy meters Gene mentioned but I do have a Kill-A-Watt 118.7 volts ac 3 motors at rest - 1.15 amps 3 motors running - 1.6 amps 4 motors at rest - 1.43 amps 4 motors running - 1.85 amps This is killing my electric bill :) Richard Love it, Richard. I have been meaning to get me one of those critters myself. Could you elaborate on the size of the motors and the PSU's output voltage? 1 - Probotix 40VDC 10Amp Linear Power Supply, no manual And linear is not as efficient, but far more tolerant of surges. What did they want for it? $85.95 It was an upgrade when I bought a V90 That would make me search my junk box. It is also a bit close to the 42 volt rating of my new drivers. Rich is not on of the bennies of being retired, darnit. In fact, I may have something I can use now that I think about it. I believe the supplies I use in series for EDM when I need to, could be paralleled as the 2 in series make about 80 volts, which when used for EDM, with a 25 ohm limiter and a 10 UF capacitor, work very well but sent me to the truck for my rifle range muffs, as it is ring your ears noisy. Now if I can just recall where I got them from because I don't want to tear that rig off the wall. I hate it when that happens. :( I'm currently running on a 28 volt switcher good for 12.5 amps if actively cooled. 42 volt rated drivers, so I would like to locate a higher voltage (36?)supply. OTOH, I've only $30 from All Electronics in this one, which also has 5 and 12 volt outputs at logic circuit currents. They are live full time but the main output is switchable, medical grade stuffs they claim. 3 - http://www.probotix.com/index.php?view=productpath=14product_id=51 # 280 Oz In. Hybrid # 1.8 /200 Steps Per Rev. # 3 Amps Current Per Phase (Uni-polar) # 8-wire Uni-polar or Bi-polar # NEMA 23 Frame 262's, 4 wire for XYA, 425 on Z, 8 wire used as 4. 1 - Pacific Scientific Powermax II stepper model P21NRXA-LNF-NS-00 http://www.electromate.com/db_support/downloads/Nema23PowermaxII.pdf 200 steps per rev 2.8 amps 8-wire I think the 28 volts is making the MM-542's run warmer, so a 36 would be better. Running at 2.4 amps, could raise that 1 notch I think. Cheers, Gene -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ 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) My web page: http://coyoteden.dyndns-free.com:85/gene Why be difficult when, with a bit of effort, you could be impossible? -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Wed, 2011-12-28 at 12:03 -0500, gene heskett wrote: There are hall effect based ammeters A while back, I mooched a Tek Hall-effect current probe from my buddy Eks to take some interesting pix: http://softsolder.com/2011/06/20/stepper-sync-wheel-current-waveform-first-light/ http://softsolder.com/2011/06/27/stepper-motor-winding-current-rise-time/ The winding current stays within a skosh of the setpoint for each microstep, which the driver determines by applying the sine cosine of the microstep (electrical) angle to the overall peak current setpoint. That may also contribute to the mystical 70% derating factor, because in full-step mode the driver (well, Allegro drivers, anyway) applies 1/sqrt(2) = 0.71 of the peak current setpoint to *each* winding. That keeps the overall motor power dissipation the same, but the total current into both windings is 2*(1/sqrt(2))*peak = 1.4*peak. Perhaps the person who first stated that factor, back in the dim past, forgot about the current in the *other* winding? While I was doing that, I managed to stoke a mechanical resonance that back-drove the winding current something awful: http://softsolder.com/2011/09/12/stepper-dynamometer-mechanical-resonance/ Keeps me off the streets at night... [grin] -- Ed http://softsolder.com -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
kqt4a...@gmail.com wrote: Just in case y'all run out of something to ponder I do not have one of those fancy meters Gene mentioned but I do have a Kill-A-Watt 118.7 volts ac 3 motors at rest - 1.15 amps 3 motors running - 1.6 amps 4 motors at rest - 1.43 amps 4 motors running - 1.85 amps This is killing my electric bill :) Yes, that's 220 W, not counting for power factor effects! So many people VASTLY overspecify the transformer, it is laughable! You see these guys with desktop mills with multi-KW power supplies. Jon -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
Just in case y'all run out of something to ponder I do not have one of those fancy meters Gene mentioned but I do have a Kill-A-Watt 118.7 volts ac 3 motors at rest - 1.15 amps 3 motors running - 1.6 amps 4 motors at rest - 1.43 amps 4 motors running - 1.85 amps This is killing my electric bill :) Richard -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Thursday, December 29, 2011 09:05:54 AM kqt4a...@gmail.com did opine: Just in case y'all run out of something to ponder I do not have one of those fancy meters Gene mentioned but I do have a Kill-A-Watt 118.7 volts ac 3 motors at rest - 1.15 amps 3 motors running - 1.6 amps 4 motors at rest - 1.43 amps 4 motors running - 1.85 amps This is killing my electric bill :) Richard Love it, Richard. I have been meaning to get me one of those critters myself. Could you elaborate on the size of the motors and the PSU's output voltage? 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) My web page: http://coyoteden.dyndns-free.com:85/gene Come on over here, baby, I want to do a thing with you. - A Cop, arresting a non-groovy person after the revolution, Firesign Theater -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
Gene, was it you I read about building edm power supply from re-wound
microwave oven transformers? Or was it somebody else who was into the edm
discussion a couple/few years back?
On Dec 29, 2011 1:36 PM, gene heskett ghesk...@wdtv.com wrote:
On Thursday, December 29, 2011 01:10:20 PM kqt4a...@gmail.com did opine:
On Thu, 29 Dec 2011, gene heskett wrote:
On Thursday, December 29, 2011 10:08:23 AM kqt4a...@gmail.com did
opine:
On Thu, 29 Dec 2011, gene heskett wrote:
On Thursday, December 29, 2011 09:05:54 AM kqt4a...@gmail.com did
opine:
Just in case y'all run out of something to ponder
I do not have one of those fancy meters Gene mentioned but I do
have a Kill-A-Watt
118.7 volts ac
3 motors at rest - 1.15 amps
3 motors running - 1.6 amps
4 motors at rest - 1.43 amps
4 motors running - 1.85 amps
This is killing my electric bill :)
Richard
Love it, Richard. I have been meaning to get me one of those
critters myself. Could you elaborate on the size of the motors and
the PSU's output voltage?
1 - Probotix 40VDC 10Amp Linear Power Supply, no manual
And linear is not as efficient, but far more tolerant of surges.
What did they want for it?
$85.95
It was an upgrade when I bought a V90
That would make me search my junk box. It is also a bit close to the 42
volt rating of my new drivers. Rich is not on of the bennies of being
retired, darnit.
In fact, I may have something I can use now that I think about it. I
believe the supplies I use in series for EDM when I need to, could be
paralleled as the 2 in series make about 80 volts, which when used for
EDM,
with a 25 ohm limiter and a 10 UF capacitor, work very well but sent me to
the truck for my rifle range muffs, as it is ring your ears noisy. Now if
I can just recall where I got them from because I don't want to tear that
rig off the wall. I hate it when that happens. :(
I'm currently running on a 28 volt switcher
good for 12.5 amps if actively cooled. 42 volt rated drivers, so I
would like to locate a higher voltage (36?)supply. OTOH, I've only
$30 from All Electronics in this one, which also has 5 and 12 volt
outputs at logic circuit currents. They are live full time but the
main output is switchable, medical grade stuffs they claim.
3 -
http://www.probotix.com/index.php?view=productpath=14product_id=51
# 280 Oz In. Hybrid
# 1.8 /200 Steps Per Rev.
# 3 Amps Current Per Phase (Uni-polar)
# 8-wire Uni-polar or Bi-polar
# NEMA 23 Frame
262's, 4 wire for XYA, 425 on Z, 8 wire used as 4.
1 - Pacific Scientific Powermax II stepper model P21NRXA-LNF-NS-00
http://www.electromate.com/db_support/downloads/Nema23PowermaxII.pdf
200 steps per rev
2.8 amps
8-wire
I think the 28 volts is making the MM-542's run warmer, so a 36 would
be better. Running at 2.4 amps, could raise that 1 notch I think.
Cheers, Gene
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Cheers, Gene
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Re: [Emc-users] stepper power supply
On Thursday, December 29, 2011 09:01:51 PM Jim Coleman did opine: Gene, was it you I read about building edm power supply from re-wound microwave oven transformers? Or was it somebody else who was into the edm discussion a couple/few years back? Nope, 'twasn't me. It was probably Ed Nisley, who did a series on that sort of stuff in Circuit Celler magazine. Perhaps he can chime in and give us pointers to the articles? But I can't put EDM in the same paragraph with that series of articles either. IIRC he was making a spot welder at the time, or something that worked on a similar principle. Even if he didn't do EDM with his setup, I suspect Ed can expound on the subject, and possibly in a more expert fashion. I have only used it twice, once to remove a pair of broken Hanson taps, and once to drill the holes in a table saw blade to allow it to be mounted on my rotary table and sharpened. So I wouldn't go out on a limb and claim to be an expert. :) From what little I know, the supply and capacitor I used the last time was really serious overkill. Yes, it got the job done, but the whole neighborhood for 2 or 3 blocks around knew that the old man was probably up to no good. ;-) 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) My web page: http://coyoteden.dyndns-free.com:85/gene Now I think I just reached the state of HYPERTENSION that comes JUST BEFORE you see the TOTAL at the SAFEWAY CHECKOUT COUNTER! -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
I assume all my steppers are using all the amps I want them to, which would be 12A if I was using 4 steppers at 3A ea. But probotix is probably assuming some reduction in current while stationary this can lead to loss of position when powered down to a lower current (it may be a requirement if insufficient heatsink is provided). This may be ok for some operations but not all. Dave Caroline -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On 28 Dec 2011, at 15:52, kqt4a...@gmail.com wrote: Would someone elaborate on this just a bit I am not questioning their response I just do not understand it I suspect that the 60% might be a diversity factor. www.wikipedia.org/wiki/Diversity_factor -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Wednesday, December 28, 2011 11:21:24 AM kqt4a...@gmail.com did opine: I have a 40v 10amp power supply from Probotix I asked this question of supp...@probotix.com I have used your 40 volt 10 amp power supply for over a year with 3 of your yellow motors (3 ammps each) I just added a 4th driver to my controller with the intent of adding a 4th 3 amp motor for a rotary table How is the 10 amp power supply going to handle 4 - 3 amp motors Am i looking for trouble I got this response The 40V 10Amp power supply is more than capable of handling all 4 drivers running the 3 amp motors. The formula breaks down like this: 3A x 4 x 60% = 7.2 amps This would be what your draw would be on the power supply. Would someone elaborate on this just a bit I am not questioning their response I just do not understand it Richard Each motor may have a 3 amp current flowing, but due to the current regulation of the chopper in the driver, with its free-wheeling diodes effect, much of that 3 amp current is circulating current between the motor and its driver, with, when the motor is stationary, only perhaps 400 milliamps actually coming from the supply when averaged. Enough to make up for the resistive heating losses in the motor and driver. Steppers working hard at higher rpms will draw more, but in the real world all 4 motors will never be running full speed continuously. If you could put a meter into the line and measure it (not recommended because the inductance of the meter will mess with the chopper waveforms back and forth into the supplies output filter capacitor, and that could destroy a driver package from overvoltage spikes on its supply input) I would doubt very seriously that you would ever see more than 4-6 amps to run all 4 motors at a good clip. There are hall effect based ammeters that could measure the current this current without the inductive effects, but they are above the range of everyone having one in his tool kit, purely laboratory instruments that in 60+ years of troubleshooting electronics, I have never felt crippled by not having one of them in my kit. As the folks here have taught me quite a few times, the cat has more than 9 lives because there are usually more than 9 ways to skin him. One can often get answers for this sort of problems from the display of an oscilloscope if you know how to read what it is telling you. IOW you should be fine. ps - I tend to bring many non-emc related questions to this list If there is a more appropriate place please point me to it While this could be OT for this list, it is not OT for quite a few of us here. I am more than happy to teach a wee bit about electronic subjects where I have some BTDT experience with them. Trying to pay back for some of the help that the real machinists here have given me over the years. Backscratching as it were. It is mutually pleasurable. :) 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) My web page: http://coyoteden.dyndns-free.com:85/gene Well, O.K. I'll compromise with my principles because of EXISTENTIAL DESPAIR! -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
chopped 3A means 3A AVERAGE the peak is much higher Dave Caroline -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
2011/12/28 kqt4a...@gmail.com: I got this response The 40V 10Amp power supply is more than capable of handling all 4 drivers running the 3 amp motors. The formula breaks down like this: 3A x 4 x 60% = 7.2 amps This would be what your draw would be on the power supply. Would someone elaborate on this just a bit I am not questioning their response I just do not understand it When stepper motor is moving, current in the windings is turned on and off, it fluctuates from 0 to 3A and back, so overall current does not reach 3A, but is somewhere inbetween. There are stepper drives, that are doing this also when motor is not moving, probably their drives are doing this. BTW I used Gecko drives for one of my machines. Their manual says that drive will draw 67% of motor winding current from the power supply. If motors are set (with DIP switches or resistor) for 3A, it will draw ~2A from power supply. Viesturs -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Wednesday, December 28, 2011 12:05:13 PM Dave Caroline did opine: I assume all my steppers are using all the amps I want them to, which would be 12A if I was using 4 steppers at 3A ea. Not so Dave. For modern chopper stabilized current controlling drivers, the power supply is only supplying the resistance and eddy current losses in the motor and driver. Worst case for really old motors with lossy iron might be 50% of the nameplate current that actually comes from the supply _once_ the current setting has been reached at initial power-up. But probotix is probably assuming some reduction in current while stationary this can lead to loss of position when powered down to a lower current (it may be a requirement if insufficient heatsink is provided). I have been amazed at how cool my motors run on the MM-542 drivers, and equally amazed at the torque it takes to turn them a full step when powered down to 50% current when idle. Yes, I _can_ turn them but they will not get moved by accident... Brushing an arm or belly against the resonance damper while hand changing tooling sure isn't going to do it. This may be ok for some operations but not all. Dave Caroline 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) My web page: http://coyoteden.dyndns-free.com:85/gene We'll know that rock is dead when you have to get a degree to work in it. -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Wednesday, December 28, 2011 12:20:36 PM Andy Pugh did opine: On 28 Dec 2011, at 15:52, kqt4a...@gmail.com wrote: Would someone elaborate on this just a bit I am not questioning their response I just do not understand it I suspect that the 60% might be a diversity factor. www.wikipedia.org/wiki/Diversity_factor From that article and its assumptions, I believe is where the term SWAG came from? ;-) 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) My web page: http://coyoteden.dyndns-free.com:85/gene To say you got a vote of confidence would be to say you needed a vote of confidence. -- Andrew Young -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
The reason they state 67% is because they are not getting the full torque from the motor They are not fully powering both windings and there is an assumption that the motors are not all in the same phase so some windings are partially powered. for full step and full power you power both windings fully. see half step and microstep sections http://en.wikipedia.org/wiki/Stepper_motor Dave Caroline -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
Well I guess if y'all are going to explain it like that then even I can understand it :) Thanks Richard -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
Sorry, but a different opinion here Gecko publishes the 67% number based on real world experience with a large number of motors and power supplies tested. The reality of calculating the current needed is daunting. First you start by looking at power, which is what is really being delivered. The Gecko drivers are modern chopping drivers which behave somewhat like a switching power supply. They convert a high voltage moderate current into a lower voltage at a higher, but regulated, current to drive the motor. For the same driver and motor the current drawn from the power supply will be different (lower current) for a higher voltage power supply than for a lower voltage one. Indeed, I have seen drivers overheat simply because the power supply voltage was too low. This is a natural result of the driver delivering a mostly constant amount of power, but having to draw more current to do so. Heating in the driver is dominated by I squared R when the MOSFETs are fully turned on, and twice the current results in four times the heat losses. Things get complicated because the power required is the sum of: 1) mechanical power delivered by the motor 2) mechanical losses within the motor (bearing and air drag) 3) resistive losses ( I squared R ) 4) hystersis losses in the iron (this is often the main cause of motor heating) 5) efficiency of the driver itself Modeling all of the above is a lot of work, even if you do have accurate data to start from. Gecko has stated that the 67% is the most you are going to need assuming you have selected a reasonable power supply voltage and are driving the motor to deliver its maximum mechanical power output. The fact that most machines only move two axes at a time for most operations will mean that the mechanical part of the power is less, but the other factors are not much effected by the mechanical power output. I generally tell my customers that 50% is good enough for typical machines, 67% will provide for anything you can ever hope to achieve, and anything more is purely for bragging rights. Regards, Steve Stallings PMDX -Original Message- From: Dave Caroline [mailto:dave.thearchiv...@gmail.com] Sent: Wednesday, December 28, 2011 1:27 PM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] stepper power supply The reason they state 67% is because they are not getting the full torque from the motor They are not fully powering both windings and there is an assumption that the motors are not all in the same phase so some windings are partially powered. for full step and full power you power both windings fully. see half step and microstep sections http://en.wikipedia.org/wiki/Stepper_motor Dave Caroline -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper power supply
On Wednesday, December 28, 2011 10:10:54 PM Steve Stallings did opine: Sorry, but a different opinion here Gecko publishes the 67% number based on real world experience with a large number of motors and power supplies tested. The reality of calculating the current needed is daunting. First you start by looking at power, which is what is really being delivered. The Gecko drivers are modern chopping drivers which behave somewhat like a switching power supply. They convert a high voltage moderate current into a lower voltage at a higher, but regulated, current to drive the motor. For the same driver and motor the current drawn from the power supply will be different (lower current) for a higher voltage power supply than for a lower voltage one. Indeed, I have seen drivers overheat simply because the power supply voltage was too low. This is a natural result of the driver delivering a mostly constant amount of power, but having to draw more current to do so. Heating in the driver is dominated by I squared R when the MOSFETs are fully turned on, and twice the current results in four times the heat losses. Another effect of a miss-match between power supply and driver is often overlooked, and that is the I*r loss in the mosfet as it is turning off this higher current during the 10-100 nanoseconds it takes to turn it off. Because more current was flowing, there are more charge carriers that must be cleared away and this loads the mosfets (hexfets) driver stage and slows in down. What this translates to in the real world is that a 48 volt driver, running on 24 volts will probably need to get rid of about 4.5 to 5 times as much heat as the *4 doesn't take this switching time difference into account. OTOH, I think we are getting closer all the time, thanks to the push for ever more efficient computer psu's, which has led to the development of ever faster switching transition times AND ever lower on resistances. I believe I benefited much from that effect when I blew the hexfet in my micromills motor controller. I looked up and printed out tha data sheet on that device, picked up a dead psu I'd had laying around for a couple years, checked the hexfets in it, and found that except for the gate capacitance going up by about 150%, every other specification was anywhere from 2 to 10x better. So I put it in, and watched it with an IR thermometer while the motor was being run at about 75% of full rpms for around an hour. I could not find a single part that was more than 15F above the background room temp and the hexfet itself was only warmed maybe 3F. So I put it back together and its still fairly well sealed inside a shack project box, about a 3.5x5.8x7 black plastic thing, sharing room with your PMDX-106. It does warm some but more than 15F of ambient. Running nicely for at least 2 years now. Things get complicated because the power required is the sum of: 1) mechanical power delivered by the motor 2) mechanical losses within the motor (bearing and air drag) 3) resistive losses ( I squared R ) 4) hystersis losses in the iron (this is often the main cause of motor heating) 5) efficiency of the driver itself Modeling all of the above is a lot of work, even if you do have accurate data to start from. Gecko has stated that the 67% is the most you are going to need assuming you have selected a reasonable power supply voltage and are driving the motor to deliver its maximum mechanical power output. The fact that most machines only move two axes at a time for most operations will mean that the mechanical part of the power is less, but the other factors are not much effected by the mechanical power output. I generally tell my customers that 50% is good enough for typical machines, 67% will provide for anything you can ever hope to achieve, and anything more is purely for bragging rights. Such a statement covers it quite well Steve. Regards, Steve Stallings PMDX 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) My web page: http://coyoteden.dyndns-free.com:85/gene People who take cat naps don't usually sleep in a cat's cradle. -- Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
