Sears air compressor trips breaker


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Old 03-03-13, 01:18 PM
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Sears air compressor trips breaker

My father-in-law's 35 gallon Sears air compressor is several years old and ran fine. Now the breaker trips after 5-10 seconds of operation. We have checked both the start and run capacitors and they check OK. We also switched breakers with no change. It runs on 110 VAC. With a DMM the motor does not show a ground. Any input is welcome.
 
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Old 03-03-13, 01:33 PM
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Welcome to the forums! some basics. What amperage breaker is in your panel for this compressor? What is the amperage of the motor as shown on the plate? You may have dirty reed valves, or a faulty unloader (my choice). Not having a ground is a personnel danger, not an operational problem, so it should be working if you have a hot wire and neutral.
 
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Old 03-03-13, 01:38 PM
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I would also suspect a faulty unloader, or check valve, and would probably start with the check valve, just because it is generally the easiest to deal with.
 
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Old 03-03-13, 01:53 PM
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Would an unloaded cause it to trip the breaker that quickly? He has tried removing the check valve assembly and it still trips the breaker. I think it's a 20 amp breaker. Not sure about the rated amps but it worked fine for years with this set-up.
 
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Old 03-03-13, 02:22 PM
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Yes, it won't take it long to realize that it is trying to start against head pressure, and stall. You are not running it on an extension cord, are you? If so, remove the extension cord, and plug the compressor directly into the receptacle; you will almost definitely experience problems using an extension cord.
 
 

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