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Checking crusty 1 1/2 hp bridgeport winding and rotor

adambomb777

Aluminum
Joined
Dec 21, 2012
Location
Newberry Springs, Ca
I know this motor is probably no good, but just wanted to learn how to properly check the components. Motor would not turn when it was removed from mill probably because of the build up between the black parts of rotor and windings. Are those black parts magnets? The bearings turn, but not very smoothly. I watched a youtube video on checking windings and did the same tests to my windings. I will post a picture of the results. Can I soak the windings and rotor in evaporust to clean them? I read you are supposed to bake them after cleaning. It is 110 degrees here, can I just leave it in the garage for a few weeks? Any suggestions on checking the windings or rotor are appreciated.
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Are those black parts magnets?

No.

The bearings turn, but not very smoothly.

Don't spin them at this time. If the seals are metal with holes then you can flush them out with solvent and palm in new grease.

Can I soak the windings and rotor in evaporust to clean them? I read you are supposed to bake them after cleaning. It is 110 degrees here, can I just leave it in the garage for a few weeks?

If you soak the rotor in evaporust you should brush off the built up corrosion first. If you soak the rotor in something else be aware that a solution like pool acid will remove the rust from the steel but erode the aluminium.

For the windings, get a couple of 2x4's and a 5 gal bucket. Place the motor housing on the 2x4's on top of the bucket. Brush the corrosion from the inside metal without touching the windings. Then squirt something like 50/50 Simple Green and water and use a tooth brush to scrub. Invert motor housing and repeat. Then use your Evaporust on the metal and invert. When clean the housing can be blown with compressed air and then placed in the sun.
 
Thank you for the detailed response. I will definitely give it a try. Do the ohm numbers look ok to you? I'm not really sure what they should be on a new or rebuilt motor.

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What you have not checked yet is for a grounded winding.
Connect 1,2,3,9 together and check to a spot filed on the frame.
It should read OL.
The other readings are close enough together for now.

Bill
 
What you have not checked yet is for a grounded winding.
Connect 1,2,3,9 together and check to a spot filed on the frame.
It should read OL.
The other readings are close enough together for now.

Bill
I think I might have been doing a star connection ohm test. Anyway here are some more connections I tested. I don't know if the t1 t2 and t3 were done correctly because I did 3 wires in each. I was thinking of my phase converter wiring for low voltage.
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That motor plate is the cleanest thing on the motor...

Look at these diagrams. You will be connecting for low volts (220v).

Your first post with the ohm readings looks encouraging.
 

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Next time, please post tumbnails instead of the big pics. Please!

In one of my past lives, I built generators. I've seen this before from a motor/genset sitting outside. We had good luck bead-blasting everything. You have to use a fine mesh bead, like 90 or smaller. Then, before you even think about putting power to it, take to a motor shop ahd have the armeteur hi-potted. Chances are that the expansion/contraction of the water has cracked the insulation. You won't see it with an ohm meter, but a hi-pot will show up.
JR
 
Next time, please post tumbnails instead of the big pics. Please!

In one of my past lives, I built generators. I've seen this before from a motor/genset sitting outside. We had good luck bead-blasting everything. You have to use a fine mesh bead, like 90 or smaller. Then, before you even think about putting power to it, take to a motor shop ahd have the armeteur hi-potted. Chances are that the expansion/contraction of the water has cracked the insulation. You won't see it with an ohm meter, but a hi-pot will show up.
JR

Most of the time I use the tapatalk app to post. I don't think there is a way to do thumbnails on the app. Also I do remember trying to do thumbnails on my old threads when I was using the computer and the resolution would be really low. Let me know how you do it and I'll give it a try when I use the computer.

I don't know anyone with a blaster. I've looked at the harbor freight blast cabinet, but probably not the best quality. ok I will call my local motor shop on Monday.
 
Ok I cleaned the motor weeks ago and it has been sitting in my very hot garage. I called to the local motor shop, 50 miles away, and he said $85.00 to check the motor. After that it would be $85.00 an hour to rebuild it He wouldn't really give me a set price. Eurton Electric, 140 miles away, gave me a quote of $575.00 to completely rebuild it. I asked him about the rotor and he said he has yet to see a rotor bad on these motors. There are a couple used motors on eBay, that have been tested to work, for around $400. What do you guys think is the best option. I know JRIowa said to do a Hi-pot test and I'm not arguing this point. This is just a question. Can I clean it up and put it all back together. Hook it up to my extension cord that connects to my safety disconnect switch with 15 amp fuses and see what it does. If the motor is already no good, would it cause any additional harm to the motor? I figured if it did anything crazy, I could just turn off the disconnect. Do I need to clean the inside of the motor where the rotor goes better?
 

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I cleaned up the rotor with a blast cabinet. From the factory, does the rotor have some type of coating on the outside? It seemed to have a black substance on it, but it is was quite dirty so I'm not sure. Should I sand the outside with really fine sand paper or just leave it like it is? Any suggestions before I put this motor together are appreciated.
 

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Today I put power to the motor for the first time and everything seemed to be running smooth. I was standing at the disconnect waiting for sparks, but to my surprise there were none. Is there anything I should check before disconnecting power? Considering the condition of the motor I am very surprised it worked at all. I attached a video, but it is right by my phase converter so it is a little loud. Thanks for the help.

Shared album - adam kington - Google Photos

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