I am going to build an RPC. I will go to an industrial junk yard to pick a used 3 phase motor, tomorrow. I do not want to buy a wrong motor.
Some questions, possibly very ignorant:
- Is TEFC better than drip proof, for me?
- Is there a difference in wye vs delta wound, as far as I am concerned?
- Do I need ball bearing or I can get away with sleeve bearing (remember, it is an idler, no load or thrust on shaft other than at startup).
- What HP to choose? With these motors essentially free, the cost difference between 10 and 7.5 HP is minimal. 10 HP, though, draws a lot more current at startup. My garage has a subpanel that is on a 60 amp breaker.
- I salvaged a 1/4 and 1/3 HP motors from two broken vacuum pumps that I had. I would buy a 5/8" ID pulley on one of them. Would they be able to spin up a 7.5 or 10 HP motor? Jim Rozen reportedly used a 1/4 HP pony to spin up a 7.5 HP motor, that makes me hopeful.
- How fast would the idler need to spin before I can remove the pony and apply 220V to the idler input?
- Is there something that I forgot to ask?