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Hi,
I need to implement a generator for my project using a small PM AC motor. The shaft speed would be 200 RPM to get output voltage of 12-15 VAC at 10-15 W. I have 2 questions:

1. How can I relate the motor specs (input voltage and output RPM) to my requirement?

2. [Can you recommend] some vendors for this small kind of AC motor.

Thanks

Alex,

I don't think permanent magnet AC motors are that common, I can only think of 1 used in a washing machine by Fisher and Paykel. These 3 phase multi-pole motors are very popular for micro hydro and wind powered alternators. They would certainly put out what you require at 200 revs. Most of the DIY guys open them up and reconnect the colis for lower voltage. As a rule of thumb I would think a motor would generate a similar voltage to that it's designed to run on.

BTW it's an alternator, generators are DC.

Regards,
Roy

Roy,

Yes, the motors will generate close to what they run on if they are running at design speed. If they run below design speed they will generate proportionally lower voltage.

Eric

With this low speed, you may need a bigger motor than you like. See http://www.anaheimautomation.com/BLZ36_Series__Brushless_DC_Motors.aspx, in particular BLZ362S-320V-3500. It seems to be the one selling for $147.40 at http://www.anaheimautomation.com/brushlessdcmotors.aspx This one is 6.6 lb, 5.03 inches long, and 3.62 inches square. This motor is 3 phase AC if used as a generator.

Eric Ratliff
www.icpdas-usa.com

Alex,

Here is a link to the motor I mentioned:

http://www.thebackshed.com/Windmill/AssemblyA.asp

Regards,

Roy

Roy,

Yes, alternator not generator. I looked at the motor you were talking about. Wow! 42 poles is a lot and I suppose this would run well at low revs.

I also want to mention that the motor I specified would put out the volts you need at zero load. As you draw up to the full 1A load, there will be some loss of voltage due to resistance of the coils.

Eric

Eric,

Yes, it is an interesting motor as is the washing machine, no gearbox, 1 moving part. Reverses back and forth to get the usual wash action with lots of different cycles and very quiet. Made in GodZone as we Kiwis call NZ but now invading Nth America.

Roy