Please Help

I need some help trying to figure out what motors I can use. I have access to AC three phase motors but I don't have a clue as to what I am supposed to be looking for. They all come off equipment large mixers, milling machines, and other pieces of equipment (some are very large in size) and are slightly used but that is all I know. I am so new to this I really don't know what questions to ask as far as the motor goes. I am sure that tons of questions will arise from this undertaking and I would appreciate any help I can get.

thanks in advance,
Dan