We arrived at the recycling center early that morning but the hunt for an induction motor was a bit disappointing because any 3 phase motor we could locate, required a fork truck to lift it. I finally asked one of the workers where they kept a 3 phase motor I could wrestle back to my truck. He turned and pointed to a huge cardboard box sitting in a corner of the shed. Still eager to find a suitable 3 phase induction motor, I began to rumage through the contents.
The surface of the Gaylord container was a smorgasborg of disassembled electric motor parts: stators, rotors, housing castings and, slightly buried in one corner, there was a 3 phase motor I was pretty sure I could wrestle to my vehicle. After I liberated the motor from the box, I could hear water sloshing inside the motor housing. I used my digital volt/Ohmmeter to check the continuity of the windings.
I then checked for open or short circuits across the windings and wether any of the circuits were grounded to the case. The electric motor checked out OK, and in spite of the water sloshing around in its interior, I bought it.
Removing the end caps and extracting the rotor from the motor housing revealed some sludge and surface rust. Examination of the stator proved that the enamel on the copper windings was in excellent shape. Aside from being covered in rust dust, the overall integrity of the physical structure of this 3 phase motor was intact making my selection of this electric motor a very good choice.
The rotor on the other hand had suffered some appearant wear and tear. The rear bearing I presume, was a recent replacement because it was tight and freewheeling. The front bearing on the other hand was completely and unretrievably trashed. There was a good 1/8th inch of lateral movement making it useless.
Without an adequate press to remove the bearing, I opted to cut the bearing free using a cutwheel on the grinder and some very steady nerves. The cutwheel must not contact the shaft in any way. The slightest nick will create a stress point that the motors' torque will find.
Think of scored glass with pressure applied. In my occupation, I have seen even low rpm 1 inch shafts snap in two from misalignment and stress. The front bearing came off without incident.
I purchased a new bearing Bushings & Bushed Bearings
I took one extra step in reviving this old motor, I soaked the stator windings with a thin varnish to help the enamel on the wires to maintain its' integrity, a little assurance just in case I missed a flaw.
After cleaning off as much scale and scum as I could, I gave this old motor a brand new suit. The final step in this process is to turn the key: Will this motor run like a scalded dog or, will my efforts end in a puff of smoke?
I read somewhere on the net that a guy ran a 3 phase motor off of single phase a.c. using a rope to start it like a lawnmower. I put that info to the test and, sure enough, the 3 phase motor started on the first pull and, though you can't tell from the photo, the 3 phase motor is running on 110v A.C.
All I need now is a prime mover to drive it............... ( Portable A.C. Generator )