Century Repulsion Start

I have a Century Repulsion start induction run motor. As best I can tell it's a pre 1939 because it has no letters in the serial number only numbers. Anyway, I had an issue with the brushes lifting. I took it back apart and freed up the centrifugal mechanism and put it back together again. Now when I plug it in it starts up fine, but as soon as the weights lift the brushes it starts to slow down as if isn't running under power anymore. I took it back apart and checked the resistance across the windings and there is no break as there is continuity across them. Any suggestions on how to proceed?

Socalpat2000 said:

I have a Century Repulsion start induction run motor. As best I can tell it's a pre 1939 because it has no letters in the serial number only numbers. Anyway, I had an issue with the brushes lifting. I took it back apart and freed up the centrifugal mechanism and put it back together again. Now when I plug it in it starts up fine, but as soon as the weights lift the brushes it starts to slow down as if isn't running under power anymore. I took it back apart and checked the resistance across the windings and there is no break as there is continuity across them. Any suggestions on how to proceed?

Click to expand...

Be sure to check it's wired for 120 - the two windings need to be in parallel. If they're in series, it's wired for 240 volts.

Socalpat2000 said:

I have a Century Repulsion start induction run motor. As best I can tell it's a pre 1939 because it has no letters in the serial number only numbers. Anyway, I had an issue with the brushes lifting. I took it back apart and freed up the centrifugal mechanism and put it back together again. Now when I plug it in it starts up fine, but as soon as the weights lift the brushes it starts to slow down as if isn't running under power anymore. I took it back apart and checked the resistance across the windings and there is no break as there is continuity across them. Any suggestions on how to proceed?

Click to expand...

Two electrical windings in that motor. The start winding is obviously working. But it sounds like an open circuit in the "run" winding.

The fault could be "outside" of where you're picking up the run winding.

Heh. Recent experience with a Carrier air conditioner. No cooling - look outside and the fan is stopped. Reach through the bars with a stick and the fan feels "lumpy" like the run coil is energized. Reason I, not starting due to issue with start circuit? Give it a BIG push with the stick and the phases "caught" and now the fan is running.

Thinking I perhaps the compressor motor has a high motor temp trip and running the fan will cool things off? NOPE - examination of the circuit shows an unusual combined start circuit - and confirms (probably) a bad capacitor.

$15 dollar capacitor which cost $80 from the Tech. And $80 for his call-out hour labor.

He served his purpose.

Try wrapping a thin string around the output shaft. MANY turns. Energize motor with the start circuit disabled. Pull string to roll the motor in its normal direction. If it catches its not the run circuit. If it stops - it is.

Joe K

Socalpat2000 said:

I have a Century Repulsion start induction run motor. As best I can tell it's a pre 1939 because it has no letters in the serial number only numbers. Anyway, I had an issue with the brushes lifting. I took it back apart and freed up the centrifugal mechanism and put it back together again. Now when I plug it in it starts up fine, but as soon as the weights lift the brushes it starts to slow down as if isn't running under power anymore. I took it back apart and checked the resistance across the windings and there is no break as there is continuity across them. Any suggestions on how to proceed?

Click to expand...

When you say it slows down like it is not under power, does it slow down until the brushes kick back on? Does it seem to be loading at all after the brushes raise or is it freewheeling? I suspect the flyweight mechanism might be lifting the brushes off before the motor approaches synchronous speed and/or perhaps the shorting necklace is not engaging.

Yes it seems to be freewheeling. I think you might be on to something with the necklace not short-circuiting. I will disassemble that next and report back with what I find. Much appreciate the assistance, as soon as I saw that it clicked. I was seeing the brushes lift and assumed the flyweights were working along with everything else.

Thanks again,

Sounds like the shorting ring is not working...Phil

Socalpat2000 said:

Yes it seems to be freewheeling. I think you might be on to something with the necklace not short-circuiting. I will disassemble that next and report back with what I find. Much appreciate the assistance, as soon as I saw that it clicked. I was seeing the brushes lift and assumed the flyweights were working along with everything else.

Thanks again,

Click to expand...

Good luck and I am sure you will figure it out. About the only thing that can go wrong with this type of motor is usually something to do with the centrifugal mechanism that lifts the brushes and shorts out the rotor. I have a 2HP Wagner that runs the line shaft in my shop. They were pretty much the same as a Century...made in the same town. When I bought it at the junk yard in was sitting in a scrap bin shaft deep in water. All I did to it, initially, was take it home and set it on a hot driveway in July and let it dry out for a couple of days. I oiled up the sleeve bearings, hooked up the crumbly old leads, put the power to it and whirl, snap, hum...it was running like a sewing machine.

Thank you for that information. It was on an air compressor that was given to me by my ex-wife's Grandfather 30 years ago or so. I was knee deep in dealing with life at the time so it sat outside, and has stayed outside ever since. I finally decided to take it apart and see if I could fix the motor as I was sure it was destroyed from sitting in the weather even though I'm in Southern California. Come to find out it really wasn't in that bad condition, or so it seems. I love this old equipment, because they sure don't build them like this anymore no matter how much you spend. The compressor pump was seized up and the crankcase was full of rusty water, but I tore it apart and I think it will work again too. I figure even if it doesn't ever work right, I have learned something. Anyway, thanks for listening, or reading, and as I said I will keep you updated.

Hello Phil, thank you for the thought. That seems to be the next step in my process. It clicked as soon as I read it from another reply that I shouldn't take for granted that the entire mechanism is working properly because part of it is doing so. So nice to have people that offer advice even if it is something simple that I should have caught.

Thanks again and I will keep you posted on the fix.

Pat

UPDATE
I took the necklace mechanism apart and it was nasty so I cleaned it up as best as I could and got it back in where it goes and didn't even lose any parts of the necklace. NOW the trick is to compress the spring while threading the cone nut onto the shaft. I have a large arbor press I am going to try and see if that works. Hey it has to go back together because it came apart without breaking it is what my dad always told me when I wanted to give up. I'll keep you all up to date on my exploits Thanks for all the input.

FINAL UPDATE:

Ok for all you folks that took the time to post a reply and help me out. I did get it cleaned up pretty good and after a LOT of finagling and fiddlin with it, along with some swearing and sweat, I was able to compress the spring on the shorting necklace enough to get the nut to thread on and tighten up. I didn't know how far to tighten it down so I took a guess. Anyway, I reassembled the motor and plugged her in. Started on repulsion and the weights flew out very quickly and it continued to run. I unplugged it so I could add the oil and not ruin the bushings. As it spun down the brushes kicked back down and there was some noise I will check out, not the brushes on armature sounding, but all in all it runs great for sitting out in the weather for 30+ years. Thank you all so much for the input and knowledge, it was a learning and rewarding experience. Now on to the next project.

I had a similar situation. One Saturday night I was in a motorcycle shop when the owner's mother called to tell him that their refrigerator quit working. We closed the shop and went to the house, where it turned out that it was one of the old units with the compressor in the basement and the cool box in the kitchen. The open compressor had a repulsion-induction motor with a similar problem It turned out that the shorting ring was thin copper alloy with little fingers that slid in and out. Some of the brushes were worn away. For reasons only the manufacturer knew, both ends of the ring had fingers and one set was untouched, so I turned it around and the motor ran fine. Mom decided I needed a reward and made a batch of cherry tarts, which were fine but her daughter came home from a date and threw a fit about me making her mother bake cherry tarts at midnight. You just can't please everyone.

Bill

And it probably ran for another 50 years. Great story, but were the cherry tarts good?

Have a great day,

Story should have ended: "And the daughter and I are still married."