jxc582,
There is an easy way to find out. Attach any 2 of the wires to a low voltage light bulb, like a 12VDC tailight bulb. Then spin the motor with your fingers. If the bulb lights even dimly it is generating power. If not it is a pure AC motor. This may be either DC or AC and still make power. This motor may be a type of electronic commutated motor, like the GE ECM motor. To find out if it is either DC or AC (if making power in test 1) use a LED. Again place the LED between any 2 leads from the motor. Slowly turn the motor by hand and watch the LED carefully. If the LED lights a little then goes out and lights and goes out then you have AC, if it glows steady, or doesn't blink, you have dc output.
All that being said try to see if a screwdriver or other steel object tries to "stick" to the body of the motor. If it does you have magnets inside. Also see if there is a acess port to service the brushes all PM DC motors have.
Sometimes the motor drive electronics can provide more info. If the motor is DC then the drive part will have a rectifier or some way to spply DC from the AC main supply. If this is a ECM type motor there will be at least one mosFET driving each of the lines leading to the motor. This ECM type of motor will usually have a much more complicated drive circuit than the DC drive types.
Finally search the net for the maker of the treadmill, or the motor, by brand name.
Hope all this helps, and good luck.
