Question about AO Smith 2 Hp Spl 3450rpm M56 Frame 115/230 Volts Replacement Air Compressor Motor Electric Motor No.B381

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High speed spa pump shuts off

Newly installed 2-speed spa motor shuts off after about a second after being switched to high speed. Does not trip breaker so apparently inside the motor. Low speed works ok.

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  • miedha2004 Feb 01, 2009

    Where would I find the Selector Switch Contact? Is it in back of the motor where other electrical contacts are located or on top of the motor inside the switch cover? Thanks for the help.

  • miedha2004 Feb 01, 2009

    I was able to isolate and fix the problem. On top of the motor is a capacitor. Upon removing the cover I observed one of the contacts on the capacitor was bent over very close to the other. When the pump was switched to high speed arcing would occur between the two shutting off the motor. A factory QC failure.


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Pump speed Selector Switch Contact Probably Missing, Checkout

Posted on Feb 01, 2009

  • Rizwan Noori Feb 01, 2009

    Can you provide me exact Specification of the pum


  • Rizwan Noori Feb 02, 2009

    As i Gave you Solution Yesterday isntead of you make any thing on it better call dealer for Service man Coz the pump comes under Warranty Periode.



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1 Answer

Taking high ampere and tripping

Remove the belt and test motor for amp draw. If motor runs normal, most likely problem with compressor or check valve. If still high amp could be short in windings or motor start switch stuck on. If motor does not turn (loud hum) try spinning by hand to see if it starts. If motors runs after spin by hand, bad capacitor. Good luck

Oct 29, 2015 | Ingersoll Rand Air Tools & Compressors

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My compressor comes on for a few second, makes a slight humming sound, then goes silent; any suggestions?

Please realize I'm not a professional compressor repairman.

Your description "comes on for a few second, makes a slight humming sound, then goes silent" leaves me guessing. When you say "comes on" does that mean it "makes the pumping sound of a compressor" or it "Clicks"? Allow my musings.

On a plugged in and turned on compressor the compressor's pressure switch turns on the pump motor when the pressure falls below it's set low pressure threshold (usually ~ 90 psi). The pumps pushes air into the pressure tank until the pressure reaches its high pressure threshold (usually ~ 120 psi). If the compressor is not plugged in or turned on you can hear a click when the pressure switch turns on.

Aside: Leaks, of any sort, make the pumping more frequent or longer. Bad leaks can make it pump continuous because the high pressure threshold is never reached. The leaks can be in the switch, at line connections or in the pump (valves or piston rings) itself.

I once had a low-volume ultra-quiet compressor that made little more noise than a hum when compressing. If yours is not an ultra-quiet (clicks on, hums, and quits) than I'd have to guess that the pump might be binding instead of pumping. If it is binding then the motor would over-heats and shuts off.

Some compressors are oil cooled. If an oil cooled compressor was extremely low on oil would it bind? I suspect so.

If you suspect binding I'd find a parts list for your model to work from and disassemble the pump to investigate. (see link below)

That's my best guess on limited information. Good luck.

Campbell Hausfeld Air Compressor Parts

Jan 16, 2015 | Campbell Hausfeld Extreme Contractor...

1 Answer

I purchaed a used T30 2475N7.5 with a three phase motor. Converted it to single phase. It acts like it is starting under a high load and kicks either the breaker or re-set every time there it pressu

it sounds like the pressure switch needs replacing as this unloads the machine from the check valve up to the heads if pressure present when trying to restart it will cause it to trip when machine stops should get air leaking from under pressure switch for 1-2 seconds then it will stop

Oct 30, 2012 | Ingersoll Air Tools & Compressors

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I have a model WL506203AJ that trips the 20AMP breaker after about 3-5 seconds of run time @ start up even w/ the tank drain open to relieve pressure. Could it be the pressure switch

Pressure relief valves don't matter since you've drained all the pressure. Either the motor has gone bad or you may have a bad contact at the switch causing high resistance and an overload.

May 02, 2012 | Campbell Hausfeld Air Tools & Compressors

1 Answer

MY mac 700 trips the internal reset switch located right above the cylinder head every time it pumps up to pressure and then shuts off. Do I need to just replace the reset switch? (it does it on different...

before to replace it ,use an amps clamp and check the amps all the way ,untill it stops and write it down,youhave to do it one wire at the time.look on you motor to see your motor amps.(usually on the name plate)dont forget to add 125% to this number.its an average rule for the service factor.(the best is to use your true service factor if you can see it but 125%will work)if your amps go over this number,check if your compreesors is not adjusted too high.(look the specs for you compressor)if your amps are fine,your pressure cut-off settings fine too,replace not bypass it if your not sure your amps are ok or you will burn the motor.if you dont know how to use a multimeter ,go on you tube and look there !you will find stuff for beginners.

Apr 16, 2011 | Makita MAC700 2 HP Air Compressor (Hot...

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Compressor won't sstay running and trip breaker

You gave a lot of information, but you didn't say if it worked when free wheeling. If not, I would suspect the inertia switch. If it is working, you should hear it click when the motor is winding down after being shut off, at least when free wheeling. A 20 amp breaker will certainly handle a 15 FLA motor, even on startup. They don't trip at 20 amps exactly, especially on a simple overload. Even at twice the rated amperage, it can take several minutes to trip it. They will trip quickly on a dead short, however, or a severe overload. I doubt the windings are shorted or it either wouldn't work (start windings) or would run at a slower speed with the inertia switch constantly tripping in and out with it coasting while tripped in (i.e., accelerate, coast, accelerate, coast, etc.)

Mar 06, 2010 | Dewalt 2 Hp 4 GAL Air Compressor

1 Answer

I have a 919.167780 2 Stage Twin V Portable

two different problems here! first when it trips the breaker and you try to reset the breaker and not turn off the compressor on its pressure switch it does not unload the air off the head of the pump when you try to start it again,,, ( when it shuts off normally you hear the air drain near the switch,, this unloads the pump to restart)

The most likely reason it is tripping the breaker is that the second stage (smaller cylinder) is not doing the work it needs to do and the first stage (bigger cylinder) is pumping more now!,,,, higher pressure on this side makes the motor work harder.

I would advise rebuilding both sides to get the pump back up to correct running levels it had new.

Feb 25, 2010 | Craftsman Air Tools & Compressors

1 Answer

Not pumping up to capacity, motor and compressor working fine,

If your pump is shutting off before it reaches it's max psi. then you need to adjust you switch. Under the black case there are two adjustment screws. One is the high\low adjustment, the other is high pressure cut off.
The first will change when the pump turns on and off for your low psi setting and the high setting simultaneously.
The second will allow you to raise or lower just the high setting. There should be a diagram under the black cap to show which is which. Adjust the high side only and just a 1\4 turn then run the compressor and see if that takes care of the high setting.

May 29, 2009 | Northern Industrial 2 Hp Twin Tank...

1 Answer

6 gallon Husky air compressor won't start

There are a few things that may have happened.
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  2. Motor did not start fast enough and it burned out your starting capacitor. This us usually located on the top of the motor under a dome shaped cover. If replacing these you must match up the mfd rating of the original and the replacement capacitor(s)
Air compressors have a fairly high draw and you should be sure that it has a proper electrical supply to it. Too small of a cord can cause the two above problems.

Also make sure that your pump is not seizing up.

Apr 15, 2009 | Campbell Hausfeld Air Tools & Compressors

1 Answer

Air compressor flips breaker before it will start?

Air compressors tend to draw more power as they age, however, will not trip breaker unless some malfunction. Here are some simple tests. Unplug compressor and turn the pump by hand, you may have to remove a cover to do this. It should turn freely; any resistance could be failing bearing (would make noise) unloader/check valve leaking allowing back pressure to pump, or failed start capacitor/start winding. Easy test for checkvalve. With pressure in tank loosen discharge hose at tank and check for air leak. Check valve should hold pressure in tank. Replace as needed. Failed capacitor/s will cause high amp draw. Remove from circuit and test. UF reading should be within 95% of printed rating. Finally, most air compressor motors have two windings, start and run. Power to windings is controlled by flyball switch inside rear of motor. This switch has contacts that can stick in start position and cause high amp draw. Examine windings for signs of overheating. Copper windings generally have color of new penny. Very dark brown windings bad news. Gook luck

Jan 06, 2009 | Air Tools & Compressors

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