Air Compressor Motor Struggling to Run

T

TomS

Active User
H-M Supporter Gold Member
My Husky 60 gal. air compressor has worked flawlessly for years until a couple of weeks ago. When I turn it on the motor starts as it should then starts to slow down after a few seconds of run time. If I open the air line drain down stream of the tank the motor speeds up to operating speed. I close the valve and the motor slows down and if left on the motor stalls. I'm not sure if this is a motor problem or something else is causing the motor to stall. If it's the motor is there a way to check it out without sending it to a motor repair shop? Could it be the tank inlet check valve, the unloader valve, or ??? For info the compressor is located in a small closet outside of my shop. No insulation and the morning temps have been in the low 20's F. and the high's in the low 40's.

Here's a photo of the motor data plate.

photo 1.jpg
 
benmychree said:
I'd look for capacitors that are not up to par, and high resistance connections (look for discoloration on connections), especially connections that are secured by screws.
Click to expand...

OK. In the morning I'll take a look at the connections. Can the capacitors be tested? Or is it best to replace them?
 
A lot of times a visual inspection of the base of the capacitor ,if bulged is an indication of a failed capacitor. Not a fool proof check,but a good place to start if a meter is not available.
 
I have one just like it here in the Caribbean. ran great for about 10yrs, then started to do the same as yours, slows down, speeds up. Replaced both caps, no change. Now, I often have to turn the flywheel by hand (power off) to get it to run. Can't find any issues with the pump, so I'm thinking the motor needs replaced. All these low cost units that have the Spl HP rating on the motors are pretty much the cheapest thing the manufacturer can find. I'd look for a better quality new or used motor for it. I'm limping by with this one because things like elect motors are hard to come by on our little island, and it's hard to get anyone to ship larger items here. Hope this is of some help. Mike
 
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In addition to checking the capacitors, also check the voltage at the motor when it is running. A bad connection in the line, pressure switch or deteriorating circuit breaker could lead to a voltage drop that could cause this.
 
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