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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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http://ef.algebra.com/e/330419557514
``First, single-phase induction motor can be used continuously operating capacitor induction motors, high power and low noise. Second, reversible motor with instant conversion does not occur almost positive super-way phenomenon. Result of the introduction of a balanced manner and contents summary winding braking institutions. Conversion is the time to blink turn, inversion. 2~4Third, electromagnetic brake motors can be a short period of time brakes, load in the absence of leave for 2 to 4 turn with brakes, brake performance to play safe. 90~1400RPM Fourth, variable speed motor speed controller with a wide range of speed: 90 ~ 1400RPM, with an internal speed sensor, the implementation of feedback control, so the frequency of power supply has changed to a number of its provisions must change. UL specifications CE motor specifications motor CCC specifications motor power specifications 60Hz115V, 50/60Hz100V, have built devices to prevent overheating of the motor and the protection of the motor impedance two specifications have been approved by UL Series. '' |
#2
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On 4/30/2010 8:34 AM, Ignoramus9191 wrote:
http://ef.algebra.com/e/330419557514 ``First, single-phase induction motor can be used continuously operating capacitor induction motors, high power and low noise. Second, reversible motor with instant conversion does not occur almost positive super-way phenomenon. Result of the introduction of a balanced manner and contents summary winding braking institutions. Conversion is the time to blink turn, inversion. 2~4Third, electromagnetic brake motors can be a short period of time brakes, load in the absence of leave for 2 to 4 turn with brakes, brake performance to play safe. 90~1400RPM Fourth, variable speed motor speed controller with a wide range of speed: 90 ~ 1400RPM, with an internal speed sensor, the implementation of feedback control, so the frequency of power supply has changed to a number of its provisions must change. UL specifications CE motor specifications motor CCC specifications motor power specifications 60Hz115V, 50/60Hz100V, have built devices to prevent overheating of the motor and the protection of the motor impedance two specifications have been approved by UL Series. '' What dressing goes best with Word Salad? http://en.wikipedia.org/wiki/Word_salad --Winston |
#3
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"Winston" wrote in message ... On 4/30/2010 8:34 AM, Ignoramus9191 wrote: http://ef.algebra.com/e/330419557514 ``First, single-phase induction motor can be used continuously operating capacitor induction motors, high power and low noise. Second, reversible motor with instant conversion does not occur almost positive super-way phenomenon. Result of the introduction of a balanced manner and contents summary winding braking institutions. Conversion is the time to blink turn, inversion. 2~4Third, electromagnetic brake motors can be a short period of time brakes, load in the absence of leave for 2 to 4 turn with brakes, brake performance to play safe. 90~1400RPM Fourth, variable speed motor speed controller with a wide range of speed: 90 ~ 1400RPM, with an internal speed sensor, the implementation of feedback control, so the frequency of power supply has changed to a number of its provisions must change. UL specifications CE motor specifications motor CCC specifications motor power specifications 60Hz115V, 50/60Hz100V, have built devices to prevent overheating of the motor and the protection of the motor impedance two specifications have been approved by UL Series. '' What dressing goes best with Word Salad? http://en.wikipedia.org/wiki/Word_salad --Winston I'd soak that one in carb cleaner for a week and see if you can get it apart. -- Ed Huntress |
#4
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On 4/30/2010 9:15 AM, Ed Huntress wrote:
wrote in message ... On 4/30/2010 8:34 AM, Ignoramus9191 wrote: http://ef.algebra.com/e/330419557514 ``First, single-phase induction motor can be used continuously operating capacitor induction motors, high power and low noise. Second, reversible motor with instant conversion does not occur almost positive super-way phenomenon. Result of the introduction of a balanced manner and contents summary winding braking institutions. Conversion is the time to blink turn, inversion. 2~4Third, electromagnetic brake motors can be a short period of time brakes, load in the absence of leave for 2 to 4 turn with brakes, brake performance to play safe. 90~1400RPM Fourth, variable speed motor speed controller with a wide range of speed: 90 ~ 1400RPM, with an internal speed sensor, the implementation of feedback control, so the frequency of power supply has changed to a number of its provisions must change. UL specifications CE motor specifications motor CCC specifications motor power specifications 60Hz115V, 50/60Hz100V, have built devices to prevent overheating of the motor and the protection of the motor impedance two specifications have been approved by UL Series. '' What dressing goes best with Word Salad? http://en.wikipedia.org/wiki/Word_salad --Winston I'd soak that one in carb cleaner for a week and see if you can get it apart. I would dunk it, except that I can't risk losing the phrase: "...almost positive super-way phenomenon." Beware of raw Babelfish! Let me put this through my Mushy Logic Converter (TM) (Beware that the MLC doesn't know anything about physics but works using only context clues and back - annotation): 1) You can continuously power a single phase capacitor induction motor from this Variable Frequency Drive. Advantages include high power conversion capability and the absence of switching transients. 2] Rotation of the driven motor will not be synchronous with that of the VFD from a dead stop but the driven motor will speed up quite quickly, nonetheless. If you turn the speed control down very quickly the driven motor will slow very quickly. Beware that the driven motor may still take some amount of time to slow to the commanded speed. 3) The VFD uses a high power D.C. pulse to safely stop the driven motor within 2 to 4 revolutions as long as the motor is set to run between 90 RPM and 1400 RPM, 4) This Variable Frequency Drive can power a single phase motor from 90 to 1400 RPM without a separate RPM speed sensor. It can be configured to power a range of different motors. 5) Rest assured that this drive is certified to comply with UL, CE and CCC requirements powering 60 Hz 115 V motors or 100 V motors normally run at 50 Hz or 60 Hz. The Drive limits power to the 'driven' motor should field windings or armature become shorted, in compliance with Underwriter's Laboratory requirements. END CONVERSION MLC V.0.0.32 I don't know anything about this stuff. Does any of this make sense? --Winston |
#5
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"Winston" wrote in message ... On 4/30/2010 9:15 AM, Ed Huntress wrote: wrote in message ... On 4/30/2010 8:34 AM, Ignoramus9191 wrote: http://ef.algebra.com/e/330419557514 ``First, single-phase induction motor can be used continuously operating capacitor induction motors, high power and low noise. Second, reversible motor with instant conversion does not occur almost positive super-way phenomenon. Result of the introduction of a balanced manner and contents summary winding braking institutions. Conversion is the time to blink turn, inversion. 2~4Third, electromagnetic brake motors can be a short period of time brakes, load in the absence of leave for 2 to 4 turn with brakes, brake performance to play safe. 90~1400RPM Fourth, variable speed motor speed controller with a wide range of speed: 90 ~ 1400RPM, with an internal speed sensor, the implementation of feedback control, so the frequency of power supply has changed to a number of its provisions must change. UL specifications CE motor specifications motor CCC specifications motor power specifications 60Hz115V, 50/60Hz100V, have built devices to prevent overheating of the motor and the protection of the motor impedance two specifications have been approved by UL Series. '' What dressing goes best with Word Salad? http://en.wikipedia.org/wiki/Word_salad --Winston I'd soak that one in carb cleaner for a week and see if you can get it apart. I would dunk it, except that I can't risk losing the phrase: "...almost positive super-way phenomenon." Beware of raw Babelfish! Let me put this through my Mushy Logic Converter (TM) (Beware that the MLC doesn't know anything about physics but works using only context clues and back - annotation): 1) You can continuously power a single phase capacitor induction motor from this Variable Frequency Drive. Advantages include high power conversion capability and the absence of switching transients. 2] Rotation of the driven motor will not be synchronous with that of the VFD from a dead stop but the driven motor will speed up quite quickly, nonetheless. If you turn the speed control down very quickly the driven motor will slow very quickly. Beware that the driven motor may still take some amount of time to slow to the commanded speed. 3) The VFD uses a high power D.C. pulse to safely stop the driven motor within 2 to 4 revolutions as long as the motor is set to run between 90 RPM and 1400 RPM, 4) This Variable Frequency Drive can power a single phase motor from 90 to 1400 RPM without a separate RPM speed sensor. It can be configured to power a range of different motors. 5) Rest assured that this drive is certified to comply with UL, CE and CCC requirements powering 60 Hz 115 V motors or 100 V motors normally run at 50 Hz or 60 Hz. The Drive limits power to the 'driven' motor should field windings or armature become shorted, in compliance with Underwriter's Laboratory requirements. END CONVERSION MLC V.0.0.32 I don't know anything about this stuff. Does any of this make sense? --Winston I have no idea, and wouldn't even try. All I could think of, as I was reading your translation, is "What if he tries it, and he's wrong?" d8-) -- Ed Huntress |
#6
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Winston wrote:
.... I don't know anything about this stuff. Does any of this make sense? Your translation is very understandable - I commend you for your perseverance. As to whether it means the same as was written, I dunno. And as to whether it is reasonable, I have my doubts. The conventional wisdom is that single phase motors can only be run within small variations of their natural speed. If this device can do what your translation says, they have a breakthrough product! I'm not going to be the one who buys & tries. Bob |
#7
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http://ef.algebra.com/e/330419557514 ``First, single-phase induction motor can be used continuously operating capacitor induction motors, high power and low noise. Second, reversible motor with instant conversion does not occur almost positive super-way phenomenon. Result of the introduction of a balanced manner and contents summary winding braking institutions. Conversion is the time to blink turn, inversion. 2~4Third, electromagnetic brake motors can be a short period of time brakes, load in the absence of leave for 2 to 4 turn with brakes, brake performance to play safe. 90~1400RPM Fourth, variable speed motor speed controller with a wide range of speed: 90 ~ 1400RPM, with an internal speed sensor, the implementation of feedback control, so the frequency of power supply has changed to a number of its provisions must change. UL specifications CE motor specifications motor CCC specifications motor power specifications 60Hz115V, 50/60Hz100V, have built devices to prevent overheating of the motor and the protection of the motor impedance two specifications have been approved by UL Series. '' And to think I got hollered at for not using paragraphs! har har...;))phil |
#8
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On 4/30/2010 2:12 PM, Bob Engelhardt wrote:
Winston wrote: ... I don't know anything about this stuff. Does any of this make sense? Your translation is very understandable - I commend you for your perseverance. As to whether it means the same as was written, I dunno. I was half - jesting with my 'translation'. I am ~92% certain that my 'translation' has little to do with the source material. And as to whether it is reasonable, I have my doubts. The conventional wisdom is that single phase motors can only be run within small variations of their natural speed. Yes, I imagine the heat build up from pushing "almost DC" through an induction motor would be very significant, especially with the restricted air flow inherent in the lower speed. If this device can do what your translation says, they have a breakthrough product! I'm not going to be the one who buys & tries. Hopefully someone who understands Technical Mandarin will translate the original for us. I am very interested in the outcome. --Winston |
#9
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He got a hunded bucks for it. That's better than anything
I've done on Ebay. Chinese, or not! -- Christopher A. Young Learn more about Jesus www.lds.org .. "Ignoramus9191" wrote in message ... http://ef.algebra.com/e/330419557514 ``First, single-phase induction motor can be used continuously operating capacitor induction motors, high power and low noise. Second, reversible motor with instant conversion does not occur almost positive super-way phenomenon. Result of the introduction of a balanced manner and contents summary winding braking institutions. Conversion is the time to blink turn, inversion. 2~4Third, electromagnetic brake motors can be a short period of time brakes, load in the absence of leave for 2 to 4 turn with brakes, brake performance to play safe. 90~1400RPM Fourth, variable speed motor speed controller with a wide range of speed: 90 ~ 1400RPM, with an internal speed sensor, the implementation of feedback control, so the frequency of power supply has changed to a number of its provisions must change. UL specifications CE motor specifications motor CCC specifications motor power specifications 60Hz115V, 50/60Hz100V, have built devices to prevent overheating of the motor and the protection of the motor impedance two specifications have been approved by UL Series. '' |
#10
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On Fri, 30 Apr 2010 17:12:21 -0400, Bob Engelhardt
wrote: Winston wrote: ... I don't know anything about this stuff. Does any of this make sense? Your translation is very understandable - I commend you for your perseverance. As to whether it means the same as was written, I dunno. And as to whether it is reasonable, I have my doubts. The conventional wisdom is that single phase motors can only be run within small variations of their natural speed. If this device can do what your translation says, they have a breakthrough product! I'm not going to be the one who buys & tries. Bob A capacitor-run induction motor is actually a two-phase motor that produces a rotating magnetic vector. |
#11
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On 5/1/2010 9:32 PM, Don Foreman wrote:
(...) A capacitor-run induction motor is actually a two-phase motor that produces a rotating magnetic vector. http://www.electrical-contractor.net...y/msp2v_01.gif So, if the claims that were *actually* made in the original source document were (for all intents) the same as the claims that I dreamt up, then it is highly likely to be fraud because the magnetic displacement of the second phase will not occur at the proper time to support armature rotation, given a significantly different operating frequency? --Winston --- Or...... not |
#12
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"Winston" wrote in message ... On 5/1/2010 9:32 PM, Don Foreman wrote: (...) A capacitor-run induction motor is actually a two-phase motor that produces a rotating magnetic vector. http://www.electrical-contractor.net...y/msp2v_01.gif So, if the claims that were *actually* made in the original source document were (for all intents) the same as the claims that I dreamt up, then it is highly likely to be fraud because the magnetic displacement of the second phase will not occur at the proper time to support armature rotation, given a significantly different operating frequency? --Winston --- Or...... not Keep in mind that I didn't even try to read the original, but Don's description of a capacitor-run motor, while accurate, doesn't explain the whole situation. Once a motor is running, it doesn't need the second phase. Furthermore, the second phase only needs to be strong enough, and close enough to proper phase, to keep the motor moving until it picks up a driving pulse from the primary phase. The capacitor typically doesn't produce a perfect "in-between" phase anyway, even at the designed frequency. In other words, in a typical application, a capacitor-run motor will start through a range of different frequencies (unless the starting load is excessive) and it will run on them, as well. That doesn't necessarily mean that it will run well, nor that it will produce normal starting torque. -- Ed Huntress |
#13
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On 5/2/2010 3:42 AM, Ed Huntress wrote:
wrote in message ... On 5/1/2010 9:32 PM, Don Foreman wrote: (...) A capacitor-run induction motor is actually a two-phase motor that produces a rotating magnetic vector. http://www.electrical-contractor.net...y/msp2v_01.gif So, if the claims that were *actually* made in the original source document were (for all intents) the same as the claims that I dreamt up, then it is highly likely to be fraud because the magnetic displacement of the second phase will not occur at the proper time to support armature rotation, given a significantly different operating frequency? --Winston--- Or...... not Keep in mind that I didn't even try to read the original, but Don's description of a capacitor-run motor, while accurate, doesn't explain the whole situation. Once a motor is running, it doesn't need the second phase. From the schematic then, the 'start' capacitor causes the current through the secondary stator winding to be 90 degrees phase - displaced in relation to the current through the primary stator only during startup? Huh! Furthermore, the second phase only needs to be strong enough, and close enough to proper phase, to keep the motor moving until it picks up a driving pulse from the primary phase. The capacitor typically doesn't produce a perfect "in-between" phase anyway, even at the designed frequency. In other words, in a typical application, a capacitor-run motor will start through a range of different frequencies (unless the starting load is excessive) and it will run on them, as well. That doesn't necessarily mean that it will run well, nor that it will produce normal starting torque. We're used to that sort of compromise when using a phase converter for example. Interesting stuff. Thanks! --Winston |
#14
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"Winston" wrote in message ... On 5/2/2010 3:42 AM, Ed Huntress wrote: wrote in message ... On 5/1/2010 9:32 PM, Don Foreman wrote: (...) A capacitor-run induction motor is actually a two-phase motor that produces a rotating magnetic vector. http://www.electrical-contractor.net...y/msp2v_01.gif So, if the claims that were *actually* made in the original source document were (for all intents) the same as the claims that I dreamt up, then it is highly likely to be fraud because the magnetic displacement of the second phase will not occur at the proper time to support armature rotation, given a significantly different operating frequency? --Winston--- Or...... not Keep in mind that I didn't even try to read the original, but Don's description of a capacitor-run motor, while accurate, doesn't explain the whole situation. Once a motor is running, it doesn't need the second phase. From the schematic then, the 'start' capacitor causes the current through the secondary stator winding to be 90 degrees phase - displaced in relation to the current through the primary stator only during startup? Huh! No, that's a capacitor-start motor. A capacitor-run motor has the capacitor in the circuit all of the time. But the actual phase in the secondary winding of a capacitor-run motor depends upon rpm (start, accelerate, or running at full speed) and, to a lesser degree, upon the load on the motor and thus the phase slippage. Unlike a good three-phase motor running on proper three-phase current, the phases aren't displaced perfectly in a single-phase, capacitor-run motor (which behaves like a two-phase motor, more or less, because of the run capacitor). There also is such a thing as a capacitor-start, capacitor-run motor, which has two capacitors, each operating in a different circuit. I've never seen one that I know of. Don't ask. g Furthermore, the second phase only needs to be strong enough, and close enough to proper phase, to keep the motor moving until it picks up a driving pulse from the primary phase. The capacitor typically doesn't produce a perfect "in-between" phase anyway, even at the designed frequency. In other words, in a typical application, a capacitor-run motor will start through a range of different frequencies (unless the starting load is excessive) and it will run on them, as well. That doesn't necessarily mean that it will run well, nor that it will produce normal starting torque. We're used to that sort of compromise when using a phase converter for example. Interesting stuff. Thanks! --Winston Any basic text on induction motors explains it better than I do here. It's worth looking it up. The Web probably has plenty of resources. -- Ed Huntress |
#15
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On Sun, 2 May 2010 06:42:14 -0400, "Ed Huntress"
wrote: "Winston" wrote in message ... On 5/1/2010 9:32 PM, Don Foreman wrote: (...) A capacitor-run induction motor is actually a two-phase motor that produces a rotating magnetic vector. http://www.electrical-contractor.net...y/msp2v_01.gif So, if the claims that were *actually* made in the original source document were (for all intents) the same as the claims that I dreamt up, then it is highly likely to be fraud because the magnetic displacement of the second phase will not occur at the proper time to support armature rotation, given a significantly different operating frequency? --Winston --- Or...... not Keep in mind that I didn't even try to read the original, but Don's description of a capacitor-run motor, while accurate, doesn't explain the whole situation. Once a motor is running, it doesn't need the second phase. Furthermore, the second phase only needs to be strong enough, and close enough to proper phase, to keep the motor moving until it picks up a driving pulse from the primary phase. The capacitor typically doesn't produce a perfect "in-between" phase anyway, even at the designed frequency. A motor designed to be capacitor-run definitely needs the second phase. Motors designed to be capacitor-run are two-phase motors. The advantage is smoother operation at rated load, much less torque ripple hence much less vibration. In a well-balanced polyphase motor torque ripple is zero. Capacitor run motors are usually employed in apps where the load is quite predictable. Once example is a buffer, another is a blower. There is no separate start cap or centrifugal switch on my cap-run 2HP buffer. I would presume that the gadget in question dispenses with the capacitor and drives both phases of the motor in proper phase relationship regardless of frequency. |
#16
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On Sun, 2 May 2010 18:24:46 -0400, "Ed Huntress"
wrote: "Winston" wrote in message ... On 5/2/2010 3:42 AM, Ed Huntress wrote: wrote in message ... On 5/1/2010 9:32 PM, Don Foreman wrote: (...) A capacitor-run induction motor is actually a two-phase motor that produces a rotating magnetic vector. http://www.electrical-contractor.net...y/msp2v_01.gif So, if the claims that were *actually* made in the original source document were (for all intents) the same as the claims that I dreamt up, then it is highly likely to be fraud because the magnetic displacement of the second phase will not occur at the proper time to support armature rotation, given a significantly different operating frequency? --Winston--- Or...... not Keep in mind that I didn't even try to read the original, but Don's description of a capacitor-run motor, while accurate, doesn't explain the whole situation. Once a motor is running, it doesn't need the second phase. From the schematic then, the 'start' capacitor causes the current through the secondary stator winding to be 90 degrees phase - displaced in relation to the current through the primary stator only during startup? Huh! No, that's a capacitor-start motor. A capacitor-run motor has the capacitor in the circuit all of the time. But the actual phase in the secondary winding of a capacitor-run motor depends upon rpm (start, accelerate, or running at full speed) and, to a lesser degree, upon the load on the motor and thus the phase slippage. Unlike a good three-phase motor running on proper three-phase current, the phases aren't displaced perfectly in a single-phase, capacitor-run motor (which behaves like a two-phase motor, more or less, because of the run capacitor). But they might be if the second phase is electronically synthesized rather than being produced by a capacitor. There also is such a thing as a capacitor-start, capacitor-run motor, which has two capacitors, each operating in a different circuit. I've never seen one that I know of. Don't ask. g The diagram at the link Winston posted is exactly that. Some consumer air compressors use this approach. They're easy to spot, there are two caps on the motor. They're sort of sneaky ******* motors. They are basically cap-start motors but they feed a little cap-run thru the start winding to get a bit more power with same temp rise and same line current with better power factor. |
#17
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On Sun, 2 May 2010 18:24:46 -0400, "Ed Huntress"
wrote: Furthermore, the second phase only needs to be strong enough, and close enough to proper phase, to keep the motor moving until it picks up a driving pulse from the primary phase. Ed, I'm surprised at you presenting such handwaving floobydust. Driving pulse indeed! Such hubris from thee, editor and illucidator of obscure contributions by the technically competent, champion of rigorous research and questor of truth? Shame on you! :) |
#18
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"Don Foreman" wrote in message ... On Sun, 2 May 2010 06:42:14 -0400, "Ed Huntress" wrote: "Winston" wrote in message ... On 5/1/2010 9:32 PM, Don Foreman wrote: (...) A capacitor-run induction motor is actually a two-phase motor that produces a rotating magnetic vector. http://www.electrical-contractor.net...y/msp2v_01.gif So, if the claims that were *actually* made in the original source document were (for all intents) the same as the claims that I dreamt up, then it is highly likely to be fraud because the magnetic displacement of the second phase will not occur at the proper time to support armature rotation, given a significantly different operating frequency? --Winston --- Or...... not Keep in mind that I didn't even try to read the original, but Don's description of a capacitor-run motor, while accurate, doesn't explain the whole situation. Once a motor is running, it doesn't need the second phase. Furthermore, the second phase only needs to be strong enough, and close enough to proper phase, to keep the motor moving until it picks up a driving pulse from the primary phase. The capacitor typically doesn't produce a perfect "in-between" phase anyway, even at the designed frequency. A motor designed to be capacitor-run definitely needs the second phase. Hmm. If you mean that it "needs" it to run well, then yes. But I don't think it needs it to run, Don. The second phase -- or the shifted phase, actually -- just smooths out the torque. And, of course, it makes the motor self-starting. Motors designed to be capacitor-run are two-phase motors. The advantage is smoother operation at rated load, much less torque ripple hence much less vibration. In a well-balanced polyphase motor torque ripple is zero. Capacitor run motors are usually employed in apps where the load is quite predictable. Once example is a buffer, another is a blower. There is no separate start cap or centrifugal switch on my cap-run 2HP buffer. I'm going to leave this discussion and let Winston study it on its own. In my experience, the motors used for blowers are almost always permanent-split capacitor motors, not capacitor-run. But my experience is pretty old. g I don't want to confuse things here with terminology. -- Ed Huntress I would presume that the gadget in question dispenses with the capacitor and drives both phases of the motor in proper phase relationship regardless of frequency. |
#19
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"Don Foreman" wrote in message ... On Sun, 2 May 2010 18:24:46 -0400, "Ed Huntress" wrote: Furthermore, the second phase only needs to be strong enough, and close enough to proper phase, to keep the motor moving until it picks up a driving pulse from the primary phase. Ed, I'm surprised at you presenting such handwaving floobydust. Driving pulse indeed! Such hubris from thee, editor and illucidator of obscure contributions by the technically competent, champion of rigorous research and questor of truth? Shame on you! :) Ah, I'd welcome a good editing. g The second, "synthesized" phase in almost all single-phase motors is usually weak and capable of little more than helping to start the motor and, in the case of a CS/CR motor, to smooth out the torque and reduce vibration. Is that better? If not, feel free to correct, and I'll leave now. d8-) -- Ed Huntress |
#20
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On Apr 30, 11:34*am, Ignoramus9191
wrote: http://ef.algebra.com/e/330419557514 ``First, single-phase induction motor can be used continuously operating capacitor induction motors, high power and low noise. Second, reversible motor with instant conversion does not occur almost positive super-way phenomenon. Result of the introduction of a balanced manner and contents summary winding braking institutions. Conversion is the time to blink turn, inversion. 2~4Third, electromagnetic brake motors can be a short period of time brakes, load in the absence of leave for 2 to 4 turn with brakes, brake performance to play safe. 90~1400RPM Fourth, variable speed motor speed controller with a wide range of speed: 90 ~ 1400RPM, with an internal speed sensor, the implementation of feedback control, so the frequency of power supply has changed to a number of its provisions must change. UL specifications CE motor specifications motor CCC specifications motor power specifications 60Hz115V, 50/60Hz100V, have built devices to prevent overheating of the motor and the protection of the motor impedance two specifications have been approved by UL Series. '' Was it originally Chinese? Somehow it looks like a different language, the verbs, articles and clauses aren't as bad as the technical nouns. Babelfish? jsw |
#21
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On 5/3/2010 6:43 AM, Jim Wilkins wrote:
On Apr 30, 11:34 am, wrote: http://ef.algebra.com/e/330419557514 ``First, single-phase induction motor can be used continuously operating capacitor induction motors, high power and low noise. Second, reversible motor with instant conversion does not occur almost positive super-way phenomenon. Result of the introduction of a balanced manner and contents summary winding braking institutions. Conversion is the time to blink turn, inversion. 2~4Third, electromagnetic brake motors can be a short period of time brakes, load in the absence of leave for 2 to 4 turn with brakes, brake performance to play safe. 90~1400RPM Fourth, variable speed motor speed controller with a wide range of speed: 90 ~ 1400RPM, with an internal speed sensor, the implementation of feedback control, so the frequency of power supply has changed to a number of its provisions must change. UL specifications CE motor specifications motor CCC specifications motor power specifications 60Hz115V, 50/60Hz100V, have built devices to prevent overheating of the motor and the protection of the motor impedance two specifications have been approved by UL Series. '' Was it originally Chinese? Somehow it looks like a different language, the verbs, articles and clauses aren't as bad as the technical nouns. Babelfish? jsw I leapt to the conclusion that it was raw Chinese Babelfish as well. Iggy, Where did you find the original? Is this the Babelfish output? --Winston |
#22
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Ignoramus9191 wrote:
http://ef.algebra.com/e/330419557514 ``First, single-phase induction motor can be used continuously operating capacitor induction motors, high power and low noise. Second, reversible motor with instant conversion does not occur almost positive super-way phenomenon. Result of the introduction of a balanced manner and contents summary winding braking institutions. Conversion is the time to blink turn, inversion. 2~4Third, electromagnetic brake motors can be a short period of time brakes, load in the absence of leave for 2 to 4 turn with brakes, brake performance to play safe. 90~1400RPM Fourth, variable speed motor speed controller with a wide range of speed: 90 ~ 1400RPM, with an internal speed sensor, the implementation of feedback control, so the frequency of power supply has changed to a number of its provisions must change. UL specifications CE motor specifications motor CCC specifications motor power specifications 60Hz115V, 50/60Hz100V, have built devices to prevent overheating of the motor and the protection of the motor impedance two specifications have been approved by UL Series. '' The Dr. Bronner's equivalent label on a motor. |
#23
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On Mon, 03 May 2010 10:46:13 -0700, Jim Stewart
wrote the following: Ignoramus9191 wrote: http://ef.algebra.com/e/330419557514 ``First, single-phase induction motor can be used continuously operating capacitor induction motors, high power and low noise. Second, reversible motor with instant conversion does not occur almost positive super-way phenomenon. Result of the introduction of a balanced manner and contents summary winding braking institutions. Conversion is the time to blink turn, inversion. 2~4Third, electromagnetic brake motors can be a short period of time brakes, load in the absence of leave for 2 to 4 turn with brakes, brake performance to play safe. 90~1400RPM Fourth, variable speed motor speed controller with a wide range of speed: 90 ~ 1400RPM, with an internal speed sensor, the implementation of feedback control, so the frequency of power supply has changed to a number of its provisions must change. UL specifications CE motor specifications motor CCC specifications motor power specifications 60Hz115V, 50/60Hz100V, have built devices to prevent overheating of the motor and the protection of the motor impedance two specifications have been approved by UL Series. '' The Dr. Bronner's equivalent label on a motor. g I used to pass by Bronner's plant in Escondido, CA back in the mid 70s. It had a 20x50' castile soap label on it. We'd pass by it in the old MG-TC every morning and grin. -- Courage is the power to let go of the familiar. -- Raymond Lindquist |
#24
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On Mon, 3 May 2010 09:14:52 -0400, "Ed Huntress"
wrote: "Don Foreman" wrote in message .. . On Sun, 2 May 2010 06:42:14 -0400, "Ed Huntress" wrote: "Winston" wrote in message ... On 5/1/2010 9:32 PM, Don Foreman wrote: (...) A capacitor-run induction motor is actually a two-phase motor that produces a rotating magnetic vector. http://www.electrical-contractor.net...y/msp2v_01.gif So, if the claims that were *actually* made in the original source document were (for all intents) the same as the claims that I dreamt up, then it is highly likely to be fraud because the magnetic displacement of the second phase will not occur at the proper time to support armature rotation, given a significantly different operating frequency? --Winston --- Or...... not Keep in mind that I didn't even try to read the original, but Don's description of a capacitor-run motor, while accurate, doesn't explain the whole situation. Once a motor is running, it doesn't need the second phase. Furthermore, the second phase only needs to be strong enough, and close enough to proper phase, to keep the motor moving until it picks up a driving pulse from the primary phase. The capacitor typically doesn't produce a perfect "in-between" phase anyway, even at the designed frequency. A motor designed to be capacitor-run definitely needs the second phase. Hmm. If you mean that it "needs" it to run well, then yes. But I don't think it needs it to run, Don. As Clinton might have said, "define run". It can limp without it once started, but it needs it to deliver rated performance. If it can't meet load while limping then it will stall, which always results in functional failure and usually results in smoke. The second phase -- or the shifted phase, actually -- just smooths out the torque. And, of course, it makes the motor self-starting. There is no difference between "second phase" and "the shifted phase actually" because a second phase can only be defined by a phase shift. A device intended to drive a two-phase motor would make said second phase in phase quadrature with said first phase regardless of frequency, and the two phases would be similar or ideally identical in magnitude. This can be approximated by a capacitor in fixed-frequency cases with predictable load as previously explained. A second phase doesn't just smooth out the torque; it is not subordinate in importance or contribution. In a properly-excited polyphase motor, all phases contribute equally to output power. A capacitor-run two-phase motor approaches this at design frequency while driving approximately design load. An external generator or producer of a quadrature second phase of similar magnitude to first phase would significanly ameliorate dependence on both load and frequency. I'm going to leave this discussion and let Winston study it on its own. In my experience, the motors used for blowers are almost always permanent-split capacitor motors, not capacitor-run. But my experience is pretty old. g I don't want to confuse things here with terminology. Terminology like "permanent split capacitor" perhaps? Induction motor technology is considerably older than we are, terminology hasn't changed in decades. Ed, being an editor does not qualify you as an engineer any more than being an engineer qualifies me as an editor. You have plenty of credentials and know a lot of stuff, don't need to fake. You are one of few posters on this NG I respect most days ... not including today. |
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Variable speed controllers do exist for single-phase motors, but they are
relatively expensive. I found several products a number of years ago, just because I was curious, as several comments here in RCM (back then), stated that single-phase motors could not be speed controlled/regulated. I don't recall the products' makers now, but the controllers weren't intended to be connected to just any common motors, such as split-phase types, although I'm fairly certain that the specific motors were not the PSC permanent-split-capacitor types. However, PSC motors are controllable with variable speed drives that are made for PSC motors. Oriental Motor (Japan) makes many models of speed controlled PSC motors and controllers, which are generally under 1/8 HP (lots of gearmotors where torque is increased by gear reduction). PSC motors can be controlled to run over a wide speed range. The AC capacitor used with PSC motors is typically a small value (under 20uF, sometimes single digit), and is wired full-time in series with one of the motor's two windings. When the capacitor is rewired differently (permanently or with an external switch), the motor rotation is reversed. One of the features of PSC motors is that they can be quickly reversed by switch motion (unlike split-phase motors which need to be stopped to reverse them). Split-phase motors, with their separate start and run windings and centrifugal switches aren't easily speed controlled, because slowing the rotor to a point where the centrifugal switch closes again (start winding energized again) is a bad idea. -- WB .......... "Bob Engelhardt" wrote in message ... Winston wrote: ... I don't know anything about this stuff. Does any of this make sense? Your translation is very understandable - I commend you for your perseverance. As to whether it means the same as was written, I dunno. And as to whether it is reasonable, I have my doubts. The conventional wisdom is that single phase motors can only be run within small variations of their natural speed. If this device can do what your translation says, they have a breakthrough product! I'm not going to be the one who buys & tries. Bob |
#26
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This description you used Don, sounds like a PSC peramanent split capacitor
motor. Is that what you were referring to? -- WB .......... "Don Foreman" wrote in message ... A capacitor-run induction motor is actually a two-phase motor that produces a rotating magnetic vector. |
#27
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As Ed mentioned, there are split-phase motors that have both a start
capacitor, and a run capacitor. The capacitors are for more torque from their respective windings/modes. As mentioned down the thread, CS-CR motors are often used on single-phase powered air compressors, but also on a lot of motors for other relatively high demand applications, up to about 10 HP (I'm fairly certain), as that's about the practical HP limit for single phase motors. The same is true of the capacitor in - just a capacitor-start split-phase motor.. more torque for starting with a significant load applied to the motor. (images mspcs_01 and 02) I don't know what was supposed to be illustrated by the gif in the link, though. I couldn't navigate to any "theory" section of the website for a description, but I did get to the directory the image is in.. http://www.electrical-contractor.net/theory/ There are 2 images of msP2v, the second image showing the rotation reversed. I think the msP represents motor, split phase, and perhaps the 2v represents reversible (as many models don't have access to the necessary terminals required for reverse rotation). The capacitors shown in the image are showing the appropriate difference in values of the capacitors, as a Start cap is a high value, and a Run cap is a low value cap. BTW, there are also diagrams representing wiring diagrams of PSC permanent split capacitor motors in that same directory, with the prefix PSC (upper case). Note that the use of the abbrev SCR represents squirrel cage rotor, not the semiconductor device. FWIW, PSC motors have 3 leads, and a resistance check will indicate 2 identical windings connected in series, similar to a center-tapped transformer winding. -- WB .......... "Ed Huntress" wrote in message ... snips There also is such a thing as a capacitor-start, capacitor-run motor, which has two capacitors, each operating in a different circuit. I've never seen one that I know of. Don't ask. g further snips Any basic text on induction motors explains it better than I do here. It's worth looking it up. The Web probably has plenty of resources. -- Ed Huntress |
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On Wed, 5 May 2010 08:37:10 -0400, "Wild_Bill"
wrote: This description you used Don, sounds like a PSC peramanent split capacitor motor. Is that what you were referring to? Apologies to Ed, I'd never seen the term "permanent split capacitor" but apparently there is such a term. I looked it up. The capacitor phase could either be a weak "helper" phase as Ed described, or it could be an essentially equal phase contributing significant torque. I would call the latter a capacitor-run motor. In such a motor, the torques contributed by the two phases are in quadrature so torque never goes thru zero which significantly reduces torque ripple and vibration. |
#29
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On 5/5/2010 5:34 AM, Wild_Bill wrote:
Variable speed controllers do exist for single-phase motors, but they are relatively expensive. I found several products a number of years ago, just because I was curious, as several comments here in RCM (back then), stated that single-phase motors could not be speed controlled/regulated. I don't recall the products' makers now, but the controllers weren't intended to be connected to just any common motors, such as split-phase types, although I'm fairly certain that the specific motors were not the PSC permanent-split-capacitor types. However, PSC motors are controllable with variable speed drives that are made for PSC motors. Oriental Motor (Japan) makes many models of speed controlled PSC motors and controllers, which are generally under 1/8 HP (lots of gearmotors where torque is increased by gear reduction). PSC motors can be controlled to run over a wide speed range. The AC capacitor used with PSC motors is typically a small value (under 20uF, sometimes single digit), and is wired full-time in series with one of the motor's two windings. When the capacitor is rewired differently (permanently or with an external switch), the motor rotation is reversed. One of the features of PSC motors is that they can be quickly reversed by switch motion (unlike split-phase motors which need to be stopped to reverse them). Split-phase motors, with their separate start and run windings and centrifugal switches aren't easily speed controlled, because slowing the rotor to a point where the centrifugal switch closes again (start winding energized again) is a bad idea. Thanks for the info, Bill. Turns out the garbled text was referring to a *gearbox* without motor in an eBay listing. Very puzzling. This has been educational nonetheless. --Winston |
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"Don Foreman" wrote in message ... On Wed, 5 May 2010 08:37:10 -0400, "Wild_Bill" wrote: This description you used Don, sounds like a PSC peramanent split capacitor motor. Is that what you were referring to? Apologies to Ed, I'd never seen the term "permanent split capacitor" but apparently there is such a term. I looked it up. The capacitor phase could either be a weak "helper" phase as Ed described, or it could be an essentially equal phase contributing significant torque. I would call the latter a capacitor-run motor. In such a motor, the torques contributed by the two phases are in quadrature so torque never goes thru zero which significantly reduces torque ripple and vibration. Thank you, Don. Now, since I'm not sitting here angry about your remarks, g and since you forced me to go back to the books, there are a few other things to clean up. Maybe you and Wild Bill already covered them. If so, I'm sorry for repeating them. I tuned out of the conversation. First, Winston was talking (he would admit it: he was babblefishing) about variable-frequency motors. I was talking about all of the conditions under which a motor may operate. You were talking about a motor with a fixed load at a fixed rpm, and then you were talking about balanced two-phase motors operating in time quadrature, which was not the subject that I thought we were talking about. As you probably noticed when you looked them up, permanent split capacitor (PSC) motors are split-phase motors with a small cap partially providing the "synthesized" second phase. The small-diameter windings on the secondary poles operate partially like a regular split-phase motor, except that they're not switched out after starting, and they provide the phase shift for starting. THOSE WINDINGS ARE NOT IN TIME QUADRATURE, except at ONE specific load/rpm combination, and they're only in quadrature because of the combination of resistance in the secondary windings and the capacitance in the secondary circuit. At any other operating condition, the voltage peaks are NOT 90 degrees out of phase. The windings are in *space* quadrature, but the reactance of the winding/cap combination can be "tuned" for only one load/rpm combination. At least, unless someone has come up with something new. I didn't look for anything new. I realize their are fancy new electronic controls, but I didn't think we were talking about them. (There are motors of this type that are not in space quadrature, either, but that's another subject.) They're very popular for fans, blowers, etc. When I last studied motors, they were the dominant type for medium-sized industrial blowers. My Googling suggests that they still are -- as I said before you jumped on me. g I don't know what you were thinking of concerning capacitor-start/capacitor-run motors, but the term always used to refer to a motor with a big-mother special electrolytic cap for starting, which is switched out at around 75% of running rpms by a centrifugal switch, and a small running capacitor. After this motor is started, it operates about the same as a PSC motor. From my Googling, it appears that this is still what it means. And neither of them are BALANCED TWO-PHASE MOTORS! Their windings are unbalanced, in terms of winding resistance, and generally in the number of windings on the secondary, plus their placement nearer the pole-ends. As unbalanced two-phase motors, THEY NEVER, EVER PRODUCE EQUAL TORQUE ON BOTH PHASES! They are in space quadrature. At one specific load/rpm, they can be in time quadrature. BUT THE CURRENT IN THE SECONDARY WINDINGS IS NEVER, EVER THE SAME AS IN THE PRIMARY WINDINGS! Thus, the second phase NEVER, EVER produces the same torque as the primary windings. That's a basic characteristic of an unbalanced two-phase motor, which these are. To quote one of the scientific papers on this subject that I just consulted, to make sure of what I remembered, the primary and secondary windings of single-phase motors with permanently engaged secondaries have an "asymmetry [that] causes an oscillating term in the electromagnetic torque." It helps smooth out the overall torque of the motor. But it is never as balanced as a true, balanced, two-phase motor. All of this contradicts several things you said in your somewhat snarky first post, if I was reading it correctly. After I saw you question PSC, I sort of tuned out and let it all go. And I'm in no mood to go back and read the thread. I don't know how you came up with two-phase motors and quadrature from all of that, because the motors we were talking about -- capacitor-start, and then PSC and cap-start/cap-run, are NOT balanced two-phase motors to begin with. Except for a few types, including the latter two types, they aren't even two-phase at all, except when they're starting. Conventional split-phase and cap-start motors switch out the secondary phase after starting, and they run as straight single-phase motors. Now, have I missed or misconstrued something you wrote? Because I admit that I was only looking at your objections, and I was annoyed. If I missed what you were talking about, I'll apologize in advance. But I've covered what *I* was talking about. I won't bore you with how and why I learned about motors. I hate electric motors and I rarely say anything in the motor threads here. I'm just not interested. But as for phases, and synthesized secondary phases, I got that from my studies in preparation for a 1st phone license with radar endorsement that I had in the early '70s. It's a very depressing subject for me so I never discuss that either. Now I'm finished being ****ed. We can just continue our usual arguments. d8-) -- Ed Huntress |
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On May 6, 2:28*am, "Ed Huntress" wrote:
.. At least, unless someone has come up with something new. I didn't look for anything new. I realize their are fancy new electronic controls, but I didn't think we were talking about them. (There are motors of this type that are not in space quadrature, either, but that's another subject.) Now I'm finished being ****ed. We can just continue our usual arguments. d8-) -- Ed Huntress Look back to the original post by Iggy which is really confusing. I am not sure if the original post is talking about a new electronic control for existing motors or a new electronic control for motors designed to be used with the new control. Not being a motor designer, I am unsure if there would be some cost advantage to a design of a two phase motor with electronic speed control over using a three phase motor with the existing variable speed controls. I would have to run a bunch of numbers to see what would be the least expensive way to have variable speed. But in every case, I think the original post was about variable speed using a two phase motor. But with how confusing the original post is, I could easily be wrong. Dan |
#32
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wrote in message ... On May 6, 2:28 am, "Ed Huntress" wrote: .. At least, unless someone has come up with something new. I didn't look for anything new. I realize their are fancy new electronic controls, but I didn't think we were talking about them. (There are motors of this type that are not in space quadrature, either, but that's another subject.) Now I'm finished being ****ed. We can just continue our usual arguments. d8-) -- Ed Huntress Look back to the original post by Iggy which is really confusing. I am not sure if the original post is talking about a new electronic control for existing motors or a new electronic control for motors designed to be used with the new control. If you can figure out what the original quote is all about, you get a medal. I think Iggy posted it as an example of extraordinarily poor explanation and confusion, either scratching his head over it or being facetious about it. Winston then made a poetic interpretation that was quite original in itself. g Not being a motor designer, I am unsure if there would be some cost advantage to a design of a two phase motor with electronic speed control over using a three phase motor with the existing variable speed controls. I would have to run a bunch of numbers to see what would be the least expensive way to have variable speed. But in every case, I think the original post was about variable speed using a two phase motor. Well, it starts off saying "single-phase induction motor." But with how confusing the original post is, I could easily be wrong. Dan Again, you get a medal if you can figure it out. Ted Frater makes beautiful medals. Maybe he'd make a Babblefish Award. d8-) -- Ed Huntress |
#33
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"Ed Huntress" wrote in message ... wrote in message ... On May 6, 2:28 am, "Ed Huntress" wrote: . At least, unless someone has come up with something new. I didn't look for anything new. I realize their are fancy new electronic controls, but I didn't think we were talking about them. (There are motors of this type that are not in space quadrature, either, but that's another subject.) Now I'm finished being ****ed. We can just continue our usual arguments. d8-) -- Ed Huntress Look back to the original post by Iggy which is really confusing. I am not sure if the original post is talking about a new electronic control for existing motors or a new electronic control for motors designed to be used with the new control. If you can figure out what the original quote is all about, you get a medal. I think Iggy posted it as an example of extraordinarily poor explanation and confusion, either scratching his head over it or being facetious about it. Winston then made a poetic interpretation that was quite original in itself. g Not being a motor designer, I am unsure if there would be some cost advantage to a design of a two phase motor with electronic speed control over using a three phase motor with the existing variable speed controls. I would have to run a bunch of numbers to see what would be the least expensive way to have variable speed. But in every case, I think the original post was about variable speed using a two phase motor. Well, it starts off saying "single-phase induction motor." But with how confusing the original post is, I could easily be wrong. Dan Again, you get a medal if you can figure it out. Ted Frater makes beautiful medals. Maybe he'd make a Babblefish Award. d8-) -- Ed Huntress The instructions were written by the people who write credit card terms and conditions. Best Regards Tom --- news://freenews.netfront.net/ - complaints: --- |
#34
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Azotic wrote: The instructions were written by the people who write credit card terms and conditions. And edited by those who publish trade journals. -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge. |
#35
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On Thu, 6 May 2010 02:28:48 -0400, "Ed Huntress"
wrote: "Don Foreman" wrote in message .. . On Wed, 5 May 2010 08:37:10 -0400, "Wild_Bill" wrote: This description you used Don, sounds like a PSC peramanent split capacitor motor. Is that what you were referring to? Apologies to Ed, I'd never seen the term "permanent split capacitor" but apparently there is such a term. I looked it up. The capacitor phase could either be a weak "helper" phase as Ed described, or it could be an essentially equal phase contributing significant torque. I would call the latter a capacitor-run motor. In such a motor, the torques contributed by the two phases are in quadrature so torque never goes thru zero which significantly reduces torque ripple and vibration. Thank you, Don. Now, since I'm not sitting here angry about your remarks, g and since you forced me to go back to the books, there are a few other things to clean up. Maybe you and Wild Bill already covered them. If so, I'm sorry for repeating them. I tuned out of the conversation. First, Winston was talking (he would admit it: he was babblefishing) about variable-frequency motors. I was talking about all of the conditions under which a motor may operate. You were talking about a motor with a fixed load at a fixed rpm, and then you were talking about balanced two-phase motors operating in time quadrature, which was not the subject that I thought we were talking about. Right. I mentioned it only to note that an electronic two-phase drive (replacing the cap) could handle variable speed and varying loads while the cap can be optimal for only one speed at rated load. As you probably noticed when you looked them up, permanent split capacitor (PSC) motors are split-phase motors with a small cap partially providing the "synthesized" second phase. The small-diameter windings on the secondary poles operate partially like a regular split-phase motor, except that they're not switched out after starting, and they provide the phase shift for starting. THOSE WINDINGS ARE NOT IN TIME QUADRATURE, except at ONE specific load/rpm combination, Correct to here, it would be good to stop here! G and they're only in quadrature because of the combination of resistance in the secondary windings and the capacitance in the secondary circuit. Resistance may enter in but isn't necessarily significant. You don't want resistance to be significant because resistance --- dissipation --- heat. But don't forget that transformation of electrical power to mechanical power appears electrically as a resistance too, one that does not produce heat in the motor because the power is delivered to the load. At any other operating condition, the voltage peaks are NOT 90 degrees out of phase. The windings are in *space* quadrature, but the reactance of the winding/cap combination can be "tuned" for only one load/rpm combination. The windings aren't necessarily in space quadrature, but you have the right idea. At least, unless someone has come up with something new. I didn't look for anything new. I realize their are fancy new electronic controls, but I didn't think we were talking about them. Oh! I did. I thought that's how this thread started. (There are motors of this type that are not in space quadrature, either, but that's another subject.) Indeed! They're very popular for fans, blowers, etc. When I last studied motors, they were the dominant type for medium-sized industrial blowers. My Googling suggests that they still are -- as I said before you jumped on me. g I don't know what you were thinking of concerning capacitor-start/capacitor-run motors, but the term always used to refer to a motor with a big-mother special electrolytic cap for starting, which is switched out at around 75% of running rpms by a centrifugal switch, and a small running capacitor. After this motor is started, it operates about the same as a PSC motor. From my Googling, it appears that this is still what it means. And neither of them are BALANCED TWO-PHASE MOTORS! Their windings are unbalanced, in terms of winding resistance, and generally in the number of windings on the secondary, plus their placement nearer the pole-ends. As unbalanced two-phase motors, THEY NEVER, EVER PRODUCE EQUAL TORQUE ON BOTH PHASES! They are in space quadrature. At one specific load/rpm, they can be in time quadrature. BUT THE CURRENT IN THE SECONDARY WINDINGS IS NEVER, EVER THE SAME AS IN THE PRIMARY WINDINGS! Thus, the second phase NEVER, EVER produces the same torque as the primary windings. That's a basic characteristic of an unbalanced two-phase motor, which these are. To quote one of the scientific papers on this subject that I just consulted, to make sure of what I remembered, the primary and secondary windings of single-phase motors with permanently engaged secondaries have an "asymmetry [that] causes an oscillating term in the electromagnetic torque." It helps smooth out the overall torque of the motor. But it is never as balanced as a true, balanced, two-phase motor. All true for those that have start windings capable of delivering brief periods of torque 4X to 10X rated run torque, which includes most motors with start windings however the start windings are disposed and excited. There are also cap-run motors, which I suppose also fit the term "permanent split capacitor" (try to order a split capacitor, permanent or temporary) that do not use a separate switched start cap. These really do work more like polyphase motors because they are polyphase motors. All of this contradicts several things you said in your somewhat snarky first post, if I was reading it correctly. After I saw you question PSC, I sort of tuned out and let it all go. And I'm in no mood to go back and read the thread. I've already apologized once. That's about infinitely many more times than you ever have for snarkey and even abusive responses to some others, so one is all you get here. The term "permanent split capacitor" was not used in my EE courses regarding electrial machinery but it apparently has become part of the jargon and vernacular since then, however misleading it might be. I don't know how you came up with two-phase motors and quadrature from all of that, because the motors we were talking about -- capacitor-start, and then PSC and cap-start/cap-run, are NOT balanced two-phase motors to begin with. That describes the motors you (not we) were talking about, I described a cap-run two-phase motor. That's relevant because the thread was about an electronic device that purports to be able to excite single-phase motors at variable speeds. I mentioned cap-run two-phase motors because they (sans capacitors) would indeed be amenable to VF drive by such a device. Perhaps I should have made that connection more clearly than I did. Except for a few types, including the latter two types, they aren't even two-phase at all, except when they're starting. Conventional split-phase and cap-start motors switch out the secondary phase after starting, and they run as straight single-phase motors. They do indeed. As such, they're not of interest here. Now, have I missed or misconstrued something you wrote? Because I admit that I was only looking at your objections, and I was annoyed. If I missed what you were talking about, I'll apologize in advance. But I've covered what *I* was talking about. Well, that's what counts! G |
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