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Thread: Pump motor capacitor

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    Pump motor capacitor

    I just replaced the start capacitor on my pump motor (AO Smith C48L2N134O2). The motor was humming, but not starting. The capacitor tested bad. New capacitor started it up with no delay. The motor ran for a couple of hours and turned itself off - it is thermally protected. When I realized it, I felt the motor and it was very hot to the touch. Took the cover off again, to find one of the yellow wires that connects the capacitor to the motor burnt nearly into. Anybody experienced this before? Thanks.
    45,000 gallon IG old (1960s??) painted concrete pool; rectangular 20' by 40' with 12' deep end; one skimmer in deep, two returns in shallow
    1 HP Hayward pump; Hayward Pro Series 300 lb sand filter Model S244T
    Aquabot T4 ("Rosie")
    TF100 Test Kit

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    mas985's Avatar
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    Re: Pump motor capacitor

    Does the motor have a centrifugal switch? If it is a capacitor start motor and the switch does not disengage the capacitor, it could damage the wiring and the capacitor.

    If it doesn't have a centrifugal switch, then it could be bad bearings causing the motor to overload.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Pump motor capacitor

    Thanks for the reply. I am not exactly sure how to tell if it has a centrifugal switch, but from your description (a switch that should disengage the capacitor once motor starts), I believe it does. It has a device near the capacitor with two springs. Looks like they would rock or tilt a stainless tab on and off of a contact. The contact has two long copper tabs on the back side of it. There is a lead that connects those tabs to the capacitor. Is this a centrifugal switch? If so, would it makes sense to attempt to replace it. Or just get a new motor?

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    mas985's Avatar
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    Re: Pump motor capacitor

    Yes, that is a centrifugal switch. It should move freely back and forth along the motor shaft. Just make sure the springs are attached and that you can move it by hand. You can also watch the switch as it spins up to see if it is disengaging the capacitor. You might try cleaning the contacts too. Sometimes they can fuse together.

    Also check the bearings while you are at it. Spin the shaft and see if it hangs.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Pump motor capacitor

    Mark, thanks again for your willingness to help and for sharing your knowledge. I took a screwdriver and could tilt/rock the switch back and forth. I can spin the shaft with my finger, about a half turn at a time. It has some resistance and if I put my ear to the outside of the motor I can hear a little bit of a rubbing sound when I spin the shaft. But not much. Should the shaft spin easier?
    I spliced wire to the burned out leads, cleaned contacts, and restarted the motor. Seems to be working fine. Will see if it turns off again. The centrifugal switch spins on the contact, but I am not sure how to tell if it is turning the capacitor off.
    BTW - for anybody reading this that is replacing a capacitor. . .there are some cast protrusions on the motor that the capacitor sits in. Make sure the lead wires are behind the capacitor and between those. I left one of the leads on the outside and believe it rubbed against the shaft causing it to short/burn out.

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    epro05's Avatar
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    Re: Pump motor capacitor

    When you replaced the capacitor, the lead that got burned may have contacted the spinning part of the centrifugal switch (resulting in the damage). This actually happened to me because I wasn't paying attention to the routing of the yellow wire. So as the motor was starting up, the wire got hit by the centrifugal switch. I actually had to splice the yellow wire back together.

    - - - Updated - - -

    You were typing as I was typing. Looks like the same thing happened to you.
    27,500 gallon in ground gunite/plaster (1995). Attached Spa with fountain, spillway, and 2 lion heads streaming into the pool. Hayward pump and AO Smith UST1152 1.5 hp motor (single speed). Hayward 60 sq ft DE Filter (Model DE-6000). Kreepy Krauly cleaner.

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    Re: Pump motor capacitor

    I do believe that is what happened to me too. Thanks for the confirmation. Maybe others can avoid a similar mistake.

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    Divin Dave's Avatar
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    Re: Pump motor capacitor

    Good to know for "just in case" I need it some day. Hopefully, I will be able to remember it by then!

    Thank y'all for figuring out what actually happened.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
    www.tftestkits.net Experience- it's what's learned just after you needed it most !!

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