# Brushless DC motor maybe ?



## major (Apr 4, 2008)

Efiero said:


> Hi i was looking at this brushless Alternator and tought this might be able to be changed to a brushless motor. they are 120 lb check it out tell me what you think
> http://www.ebay.com/itm/121246067990?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_265wt_662


Why do you think it is a brushless machine And while it is probably possible to make any alternator or generator into a motor, it may be very difficult, especially for the controller, and may end up being inefficient as a motor.


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## Efiero (Feb 7, 2009)

Why i was thinking this is due to the stator looks to be wound as 3 phase and since it is brushless i would imagane the rotor must have magnets in it so it is set up just like a BLDC motor but would need to take each phase and hook it up to the controler + some sensors that was my thinking but i could be all wrong


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## major (Apr 4, 2008)

Efiero said:


> Why i was thinking this is due to the stator looks to be wound as 3 phase and since it is brushless i would imagane the rotor must have magnets in it so it is set up just like a BLDC motor but would need to take each phase and hook it up to the controler + some sensors that was my thinking but i could be all wrong


Niehoff does make brushless alternators. But they are not PM. They use wound field. At any rate, it will be difficult to make a controller for it to run as a motor and it will have poor efficiency, <70%.

ref: http://www.ceniehoff.com/static.asp?path=78


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## Efiero (Feb 7, 2009)

i dont realy understand what or how it would work without a magnet on the rotor or no brushes could you explain or give me a link i just like to know how things work thanks


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## major (Apr 4, 2008)

Efiero said:


> i dont realy understand what or how it would work without a magnet on the rotor or no brushes could you explain or give me a link i just like to know how things work thanks


I've never seen that particular machine but know other alternators (AC generators) use a wound field (electromagnets) rotor which is excited (powered) brushless thru what amounts to a rotary transformer called an exciter. It sometimes looks like a small generator hung on the shaft of the larger generator.

Example: http://avstop.com/ac/Aviation_Maintenance_Technician_Handbook_General/10-163.html


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