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In Reply to: RE: I am not sure of your meaning.. posted by kentaja on December 17, 2016 at 14:50:31
See my response above to John Ellison.
However, I do take your reservations seriously, because I respect your experience. Can you say whether you have made measurements of the power requirements of the Lenco motor that would support your view? Or is this scuttlebutt from Lenco Heaven, which would also cut some ice with me?
I've been running my Lenco off the Walker PMC, which by all accounts is slightly less powerful than the 25W Eagle. I don't notice any problem, no over-heating of the Walker or speed irregularities of the Lenco, that would point to power starvation. On the other hand, the Walker effect is not as profoundly obvious with the Lenco as it once was when I used the Walker to drive my previous Notts Hyperspace. On that tt, the Walker was a revelation.
I found this quote from "Pyramid" (Bill Carlin, I think) on DIYAudio:
"AC synchronous motors are locked to the driving frequency so the speed is controlled by changing frequency not voltage. The speed (RPM) is Freq x 60/#pole pairs. So for a 12 pole motor at 60 Hz, the speed is 3600/6 or 600 RPM. A 300 RPM motor (designed for 60 Hz) has 24 poles. We can change the frequency of the output signal in 35µHz steps so the speed control is very precise. The factory default frequency for 33.333 RPM is 60Hz, but in calibration mode, you can adjust this in 0.01 RPM steps. Once the base frequency is set, changing the "tempo" setting in 0.1 RPM steps using the +/- buttons is easy and the speed stays synchronized and accurate.
AC synch motors also exhibit no loss in speed due to torque loads. They hold 100% of their speed until the cogging torque is exceeded at which point the speed drops to zero. This is not true with DC motors or AC induction motors. DC motor speed is controlled by voltage, therefore our controllers do not work with them; AC induction motor speed is a function of frequency and voltage, although the speed is not locked to the driving frequency as in AC synch motors, but is related so speed control is a little more difficult."
Up to now, I had thought that the Eagle worked on AC synch motors only, by changing AC phase. And I would have thought that voltage was more important than phase in affecting torque and speed of induction motors, which is why I never looked further into the Phoenix products. But I guess the Eagle will work on the Lenco, as testified to by many apparently happy users.
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