I was working on an old trane package unit. The tag indicates a 1/3hp fan motor. The replacement motor that had been replaced a few years back was a 3/4hp 1075 rpm.

The blade was in bad shape so I got one that was close to original. I put on a 1/3 hp 1075 motor . And it was pulling almost 3 amps. Motor is rated for 2 amps.

Is there a way to figure a good replacement motor.