Electric motors have a good value at a scrap yard due to their copper wiring interiors.  Generally speaking, we don't recomend breaking down electric motors as they are hard to open, unwind, and separate and takes a lot of time for each unit.  The copper wire inside is a #2 grade wire and would not get you top dollar if separated and sold.  Electric motors are a popular items at scrap yards, we suggest calling your local yards and asking for prices for whole units.  These are paid by the weight.