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Old 03-21-2017, 12:09 AM   #3068 (permalink)
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Originally Posted by HaroldinCR View Post
These have an encoder or resolver with 10 poles. The stator is 72 poles and the rotor is 56 poles.
I heard that in the video too. It confuses me a bit

The encoder should have at least 10 pulses per revolution. But the lobes on the shaft don't look like they are driving discrete signals. Maybe I need my eyes checked? It kinda looks more like lobes on a resolver?

freebeard, RPM's of the altermotor get to 30,000 when driven by the stinko engine. Altermotor has a 175A fuse and uses a 115V battery. Possibly 60 HP ??
I'm going to talk this through .. or maybe type this through?

3600 / (2 * poles) = rpm. 72 poles is kinda high. Like 25 rpm at 60 Hz.

Maybe 72 slots in the stator? That would make more sense.

The slots are overlapped, so the same slot seems to be used for 2 windings. They are stacked on top of each other.

The configuration is Y, so there is a center point that he shows at the back, and it looks to me like 3 pairs of windings are connected together to form the center point. But I don't see video of the other end, so there may be many coils in parallel for each phase or they could mostly be in series. It looks like the phase terminals have at least 2 coil connections on them.

I'm not a motor guy - I think the windings are put in series and parallel to balance out the phases for voltage and current. But we can't see the other side of the stator. 72 pairs of poles / 3 phases = 24 coils each. With no other information, and given the high rpm ... I'd say the coils are in series. 2 sets of coils each on the motor terminals means .. to me .. at least 2 coils per phase, meeting at the center point. So that would be 2 poles. But there could be hidden connections on the other end of the stator.

30,000 rpm is pretty high. If it's 2 pole, that generator would put out .. 500 Hz? With no slip? At 4 pole, the output would be 1000 Hz. 6 pole, 1500 Hz. That is quite high for a controller to put out. The carrier frequency is usually in the 4000 - 16000 Hz, 4 - 16 Khz range ... and it needs to make the pulses look like a sine wave to the motor. I must be missing something.

At 60 HP, 30,000 rpm gives not very much torque. 10 foot-lb or so.

So my guess would be a 2 pole generator, rated for 30K rpm, that will put out (or consume) 500 Hz at that speed, with about 10 foot-lb of torque. I know that the slots in the rotor are a factor in the output frequency, but I don't know how.

I'm sure that someone else will chime in!
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