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Thread: Pump motor still trips breaker after replacing capacitor

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    Pump motor still trips breaker after replacing capacitor

    Hello all.

    About 10 days ago, I noticed that my pump wasn't running. The breaker was tripped, and when I reset it, the motor hummed and then tripped the breaker again. I looked around on the internet (including here) and figured the capacitor was bad. I was able to turn the shaft by hand. Motor is 2hp made by US Motors, installed 3 years ago. I replaced the shaft seal a couple of months ago because I noticed I had a leak.

    Ordered a new capacitor, same ratings as the old one (50 uF, 370VAC). installed it today, and the pump ran for a few hours and I though my problem was solved. I happened to be outside, and noticed that the motor was sounding different. It was making a somewhat high-pitched sound besides its usual sound. Then the breaker tripped again. Tried resetting the breaker, but the motor just hummed loudly then tripped the breaker again.

    Could the replacement capacitor be a lemon? Anything else I could try before calling someone to make the necessary repairs for me? I was hoping to be able to do it myself, but may be in over my head.

    Thanks in advance!
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    Re: Pump motor still trips breaker after replacing capacitor

    Do you have an amp probe? Or know someone who does? If you get one: Start pump and run it, put amp probe on black wire on incoming power line, assuming its a 120 volt motor; 220 volts it does not matter which wire (wherever you can access it). Read the amount of amps being drawn. Now, look on the motor nomenclature look specifically for a RLA number this means Run Load Amps. Compare your actual amps to RLA if you are exceeding then there is another issue going on. For example RLA rating 10 actual 9.5 that would be normal. IF you where reading say a 12 amps then it means the motor is overloaded and could possibly trip a breaker. If its is overloading then *could* be a capacitor, pump failure (bearing) causing excessive load, has anything changed in the plumbing? Pushing the pump beyond its capabilities? Also I would check all connections from the breaker panel to the pump motor a loose connection would cause hard starting and will trip a breaker once things start heating up. Start with these items and we will go from there, there is more you can try but start here.

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    Re: Pump motor still trips breaker after replacing capacitor

    The motor numbers to ID it would be helpful.

    Is there a chance it has both a start and run capacitor ??
    '70s IG Vinyl 32K gal, Lazy L, Hayward SuperPump 1.5hp 120V, S240 Sand Filter W/DE
    Solar Blanket, Well Water, Borax Added, TF-100 tester. ? too cold
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    Re: Pump motor still trips breaker after replacing capacitor

    High pitched whine is probably the bearings. Just buy a new motor and seal and install it. It really isn't that hard, I've done it at least 4 times already.

    Quote Originally Posted by caliking View Post
    Hello all.

    About 10 days ago, I noticed that my pump wasn't running. The breaker was tripped, and when I reset it, the motor hummed and then tripped the breaker again. I looked around on the internet (including here) and figured the capacitor was bad. I was able to turn the shaft by hand. Motor is 2hp made by US Motors, installed 3 years ago. I replaced the shaft seal a couple of months ago because I noticed I had a leak.

    Ordered a new capacitor, same ratings as the old one (50 uF, 370VAC). installed it today, and the pump ran for a few hours and I though my problem was solved. I happened to be outside, and noticed that the motor was sounding different. It was making a somewhat high-pitched sound besides its usual sound. Then the breaker tripped again. Tried resetting the breaker, but the motor just hummed loudly then tripped the breaker again.

    Could the replacement capacitor be a lemon? Anything else I could try before calling someone to make the necessary repairs for me? I was hoping to be able to do it myself, but may be in over my head.

    Thanks in advance!
    8000 gal diamond brite pool with 650 gal spillover spa, Pentair 3hp VS pump. Jandy Cartridge filter and Jandy Heat Pump. Jandy PDA automation system with 2 Pentair Laminars. SmartPool NC74S Robotic Pool Cleaner.

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    Re: Pump motor still trips breaker after replacing capacitor

    OR . . . IF the bearings are a problem, rebuild it yourself.

    https://www.youtube.com/watch?v=CcrHwAL7V7w
    '70s IG Vinyl 32K gal, Lazy L, Hayward SuperPump 1.5hp 120V, S240 Sand Filter W/DE
    Solar Blanket, Well Water, Borax Added, TF-100 tester. ? too cold
    1979, 275gal Conway Emerald Spa P-100-2, ES-2 Spa Pack, bromine floater, indoor
    TF-100, Best test kit - TFTestkits.net
    Please help keep the lights on, become a TFP Supporter!

  6. Back To Top    #6

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    Re: Pump motor still trips breaker after replacing capacitor

    2015-03-29 12.11.01.jpg

    - - - Updated - - -

    I posted a pic with the motor details. I think it is the bearings, because of the high pitched screeching just before it started tripping the breaker again. Also, the motor had been sounding much louder prior to stopping the first time. The motor did run for a few hours when I replaced the big capacitor at the end of the motor.

    - - - Updated - - -

    Quote Originally Posted by Pool Noob View Post
    Do you have an amp probe? Or know someone who does? If you get one: Start pump and run it, put amp probe on black wire on incoming power line, assuming its a 120 volt motor; 220 volts it does not matter which wire (wherever you can access it). Read the amount of amps being drawn. Now, look on the motor nomenclature look specifically for a RLA number this means Run Load Amps. Compare your actual amps to RLA if you are exceeding then there is another issue going on. For example RLA rating 10 actual 9.5 that would be normal. IF you where reading say a 12 amps then it means the motor is overloaded and could possibly trip a breaker. If its is overloading then *could* be a capacitor, pump failure (bearing) causing excessive load, has anything changed in the plumbing? Pushing the pump beyond its capabilities? Also I would check all connections from the breaker panel to the pump motor a loose connection would cause hard starting and will trip a breaker once things start heating up. Start with these items and we will go from there, there is more you can try but start here.
    I don't have an amp probe. I think the bearings are bad, based on what others have described elsewhere on the forum and the responses here. Could worn out bearings cause the capacitor to malfunction? The original capacitor and now the replacement capacitor are not bulging out or looking shorted out or anything.
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    Re: Pump motor still trips breaker after replacing capacitor

    If I replace the motor, any ideas on which one to buy and from where? The current motor replaced an AO Smith one, which I think most likely just had a bad capacitor, but I had not found this forum back then.

    I think I still have that motor somewhere, so one thought would be to get a new capacitor and install that instead. It was in use for about 9 years I think. I'm starting to think that my current motor is not a very good one. Purchased from leslie's, installed it myself, but in less than 3 years, the shaft seal went bad, and now looks like the bearings are shot.

    If I opt to change the bearings out, how do I know what size bearings I need? Best place to purchase?
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    Re: Pump motor still trips breaker after replacing capacitor

    I don't think bearings are all that easy to change. New motor is around 245 bucks it looks like from electric motor warehouse, they usually have the best prices.
    8000 gal diamond brite pool with 650 gal spillover spa, Pentair 3hp VS pump. Jandy Cartridge filter and Jandy Heat Pump. Jandy PDA automation system with 2 Pentair Laminars. SmartPool NC74S Robotic Pool Cleaner.

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    Re: Pump motor still trips breaker after replacing capacitor

    Quote Originally Posted by robl45 View Post
    I don't think bearings are all that easy to change. New motor is around 245 bucks it looks like from electric motor warehouse, they usually have the best prices.
    I may end up buying a new motor. Changing the bearings looks like something I could accomplish, but time is at a real premium at the moment with a 1yo at home and recently starting a new job. Thanks for the info.
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    Re: Pump motor still trips breaker after replacing capacitor

    As follow-up to my issue, I ended up replacing the motor with a Century/AO Smith 2HP motor. $280 on Amazon. Installed it 3 days ago, and things seem to be running smoothly. The new motor is MUCH quieter than the old one. Thanks everyone for the helpful advice.
    ___________________________________________________

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