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Thread: 2 speed motor keeps going into thermal overload

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    Join Date
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    Sachse, Texas
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    2 speed motor keeps going into thermal overload

    Here's the background: I had a catastrophic failure in February. The freeze control failed and caused the filter bowl for the pool sweep to crack, when the pump cycle turned on, the pump ran dry and caused the motor windings to MELT. I replaced the small filter bowl and the motor, same type and size, AO Smith STS1152R. made the wire connections and turned the breaker back on. The digital controller gave the pump icon to indicate that it was on, but the motor would not start. I abandoned the controller in order to get the motor up and running while the new controller was on order, Intermatic PE15300 with freeze control. I wanted to just get the motor going and run it only on hi speed until the new controller came in. I connected the green wire to ground, black to hi speed and red to common and taped off the white wire since I had bypassed the outside switch and GFI and planned to use the breaker at the main power to turn the motor on and off. It worked beautifully, measured 120 volts from black to ground and 120 volts from red to ground for a steady 240 volts. Problem is, the motor will run for about 34 minutes (after some trial and error). So I just set a timer and ran it for 32 minutes then shut it down manually. If it runs longer than 32 minutes, the motor shuts off by the thermal overload protection. It does not trip the breaker at the main panel and will restart after an hour cool down or so. What is the problem? It's hot in Texas and getting difficult to keep the water clear. The new part from Intermatic has been on terminal backorder due to some manufacturing glitch. Can I get this thing going like it is to wait out the backorder?
    20k Plaster Pool
    175 SQFT Star-Clear Cartridge Filter
    2 Speed 1-1/2 - 1/2 HP AO Smith STS1152R Motor
    Hayward Super II Pump
    Eco-matic ESC-48 Salt System

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    JasonLion's Avatar
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    Re: 2 speed motor keeps going into thermal overload

    Welcome to TFP!

    Make sure your pump is designed to sue 240 volts, and then double check that you are actually supplying 240 volts. Wiring 120 to 240 volt pump and wiring 240 to a 120 volt pump can both cause the symptoms you are describing.

    There is no absolute need to get the timer thing figured out right away. The motor should work just fine with or without the timer.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: 2 speed motor keeps going into thermal overload

    The pump motor plate indicates 230 volts as did the sticker on the new motor advising that it was wired for 230 volts. I checked each leg individually and got 120 volts, they were at 240 volts when measured together.
    20k Plaster Pool
    175 SQFT Star-Clear Cartridge Filter
    2 Speed 1-1/2 - 1/2 HP AO Smith STS1152R Motor
    Hayward Super II Pump
    Eco-matic ESC-48 Salt System

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    Jul 2014
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    Sachse, Texas
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    Re: 2 speed motor keeps going into thermal overload

    Is it possible that the run capacitor is bad, it doesn't have any visual signs of damage.
    20k Plaster Pool
    175 SQFT Star-Clear Cartridge Filter
    2 Speed 1-1/2 - 1/2 HP AO Smith STS1152R Motor
    Hayward Super II Pump
    Eco-matic ESC-48 Salt System

  5. Back To Top    #5
    JasonLion's Avatar
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    Re: 2 speed motor keeps going into thermal overload

    Yes, the run capacitor could be an issue, but the odds of that being bad on a new motor are very low.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: 2 speed motor keeps going into thermal overload

    Sorry, bad answer head buried in sand filter. Edited my answer as I was strictly thinking of a starting capacitor and Jason pointed out the possibility of a run capacitor also.

    So - maybe but pretty unlikely.

    Are you sure the replacement is the same or better HP and service factor as the original ?? Any chance you can post the info off the melted motor, had it recorded somewhere, old picture of the tag ??

    Update: should have looked up the specs before I push my keys. It is a capacitor run, 1.5hp 1.3 SF

    Pool Pump Motor, Open Drip Proof, Capacitor-Start/Capacitor Run, 1 1/2 HP @ High RPM, 1/4 HP @ Low RPM, 3450/1725 RPM, 56J NEMA Frame, 230 Voltage, 9.0/3.3 Full Load Amps, C-Face Mounting, Auto Thermal Protection, 1.3 Service Factor, Ambient 40 C, Insulation Class B, CCWPE Rotation, Bearings Locked Double Sealed Ball on Shaft End, Efficiency Group High, Shaft Diameter 5/8 In, Shaft Length 2 9/16 In, Shaft Type Threaded, 303 Stainless Steel Shaft, Aluminum Flange, 60 Hz, Black Finish
    '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
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  7. Back To Top    #7

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    Re: 2 speed motor keeps going into thermal overload

    I wish I still had the old motor, but it's long gone. HP and voltage rating are the same for sure, could that same size have a different SF on a new pump?
    20k Plaster Pool
    175 SQFT Star-Clear Cartridge Filter
    2 Speed 1-1/2 - 1/2 HP AO Smith STS1152R Motor
    Hayward Super II Pump
    Eco-matic ESC-48 Salt System

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    Kiss4aFrog's Avatar
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    Re: 2 speed motor keeps going into thermal overload

    Just wondering if the motor was driving too big an impeller but if the old motor was turning it OK and it was a 1.5 hp the SF likely wouldn't make enough of a difference. Did you inspect the pump impeller and housings to make sure they weren't warped or ???? anything that looked odd.

    Have you tried customer service to see if they might know ?? The fact that the overheating is so predictable (34 min) is what seems so odd.

    Please note: A. O. Smith sold its electric motor business to Regal Beloit Corporation in 2011. If you have a motor question, call 1-800-543-9450 or visit the Century Electric Motor website.

    - - - Updated - - -

    I didn't see anything in here but maybe someone else might: http://www.centuryelectricmotor.com/Motor-Doctor-Article.aspx?LangType=1033&id=775
    '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!

  9. Back To Top    #9

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    Re: 2 speed motor keeps going into thermal overload

    If voltage is correct, the only way to see if the service is cause or if motor is, is to see the amperage draw. Got inductive meter?
    Factory Warranty Station for:
    Jandy/Zodiac, Pentair, Sta-Rite, Raypak, Polaris,
    and Paramount pool cleaning systems.

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