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  1. #1
    Platinum Member
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    May 2005
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    Eastern WA
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    Jinma JM354

    Default electric compressor motor

    I apologize if I'm in the wrong forum but I use my compressor a lot and the motor quit. Kept tripping the breaker. It's worked fine for about twenty years. It's a 5 hp single phase reversable 230 volt Ajax motor. Ajax motor company no longer in buisness, of course. It's got two start capasitors and two run capacitors. I check with ohmeter and found one start bad it did differently from the other in that it wouldn't go up scale. Even with the new cap. no go, just hums. I checked with local motor shop and he said maybe a stationary switch may be the culprit. I guess the motor has two switches one stationary and one rotary to take the start winding out of circuit. My question is do I stand a chance of finding replacement switches? I mean are they generic or manufacturer specific? A complete motor replace is over $500 way more than I gave for the original complete compressor. A wiring schematic showing the two start and two run would be helpful also. There's a small diagram on motor but too small for me to see. bjr

  2. #2
    Elite Member Redneck in training's Avatar
    Join Date
    Nov 2008
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    2,787
    Location
    South Central Iowa
    Tractor
    TYM 330 HST with FEL

    Default Re: electric compressor motor

    I checked on Internet. Looks like the Ajax Electric Motor Corp. is still in business. Here is a link to motor parts supplier. Good luck.
    Electric Motor Service
    http://www.americanelectricmotors.co...pg1-cid49.html

  3. #3
    Elite Member George2615's Avatar
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    Feb 2005
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    4,641
    Location
    Central Square, NY
    Tractor
    LS XR3037HC

    Default Re: electric compressor motor

    Graingers has many compressor motors. You already have the volts, just get the rest of the motor specs off the tag (such as rpm, frame, amps, etc) and match up a standard replacement motor. I think TSC and Northern tool have compressor motors also.


    Grainger Industrial Supply

  4. #4
    Veteran Member
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    Jul 2004
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    1,632
    Location
    Bancroft, Ontario
    Tractor
    JD4300

    Default Re: electric compressor motor

    5HP is a pretty large single phase motor. I would take it to a motor shop and ask them. If its the start switch then it should be a minor item. If the windings are burnt out then it will get pricey....

  5. #5
    Platinum Member
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    May 2005
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    Eastern WA
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    Jinma JM354

    Default Re: electric compressor motor

    Udate on the compressor motor. I had electrician buddy come try to fix it and he took the end cover off and blew out 32 yrs of dirt and dust. He said the contacts in the stationary switch look as though they should function okay. Then we check the capacitors again with a scaling fulke meter and they appeared okay. Now I think the motor shop I talked to said they had a dedicated capacitor testing equipment. So our test with the ohmeter may have not not been conclusive. We did get the compresser to turn at low speed but not come up to speed. I don't know if that means the start circuit is okay and something in the running circuit not okay? I didn't try ohming the motor run windings. Any thoughts here on the motor not coming up to speend? Remember there two start capacitors and two run capacitors here. bjr

  6. #6
    Elite Member
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    Oct 2004
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    limerick pa lycoming county pa
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    kubota bx23

    Default Re: electric compressor motor

    Did you try starting it with the belt off?
    Dose the centrifugal switch arms or weights move freely when you had the end bell off?
    Can you see the switch move when it starts up?
    It sounds like its staying in start mode ot the start winding is open

    here is a link to read through. Electric Motor Basics

    and motorsanddrives.com - Motor Types

    tom
    If it ain't broke we will help you brake it
    If it is broke we will help you get it fixed!


    https://www.facebook.com/joseph.t.mussington

  7. #7
    Platinum Member
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    May 2005
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    Eastern WA
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    Jinma JM354

    Default Re: electric compressor motor

    The guy I had look at it said all that (centrifugal and the stationary switch) was working as it should. It's at a motor shop now, we'll see what that guy says. I get back as soon as I know something. bjr

  8. #8
    Super Member
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    Sep 2000
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    6,553

    Default Re: electric compressor motor

    We are assuming that the compressor pump is not binding up ...

    jb

  9. #9
    Platinum Member
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    May 2005
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    Location
    Eastern WA
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    Jinma JM354

    Default Re: electric compressor motor

    Compressor turned fine. I just did get a call from the shop that I took it to and he said they tested every thing on the motor, IE windings and capacitors, and put everything back together and it started just fine. Maybe I got a capacitor wired wrong, I've been wrong before when I thought I had things wired right that were not. I'll pick it up tonite and see what happens. bjr

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