# 8 Hp BLDC Motor



## BobDiode (Apr 16, 2009)

A sensorless controller is all you need. If you make a magnetic PM rotor or buy a Delco PM alternator the PM rotor is already installed and there is no need to waste power energizing the field coil.
If you do want a sensored controller to commutate the rotor you must make a hall sensor board using three $1. hall sensors that can be epoxied to a fiberglass board and mounted in the right place for 120* timing.
http://www.youtube.com/watch?v=cxj4i5VLxf8

This is a small 5 lb Ford PM Alternator / Motor with a hall sensor board and hall sensor controller used for a Electric bike that goes 45 MPH.
http://www.youtube.com/watch?v=Q5kwH1Nkpr0 

This is using 2.5 amp hours from a 5 ah 66.6 volt lithium battery pack. The 5 pound motor was made from the smaller old style Ford alternator with a 12 pole PM rotor.



The picture below is a Delco with and without a PM rotor. Notice that with the Claw Pole rotor without a PM rotor needs a pill magnet disk used to trip the hall sensors. A sensorless ESC is much easier and does not need hall sensors or a commutation disk, but you will not get low rpm torque because of errors in commutation. Sensord hall sensors are preferred for smoothness, efficiency and high torque from a standing stop.


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