I have a Sears 30 gallon compressor and I plugged an extension cord into it. It started and was running perfectly until I did this. I could hear the motor was not running as loud as before when I had it plugged directly into my outlet. After I used some air and needed more, it will not start now! Any ideas, says Royce.
I tried to find a photo of a 30 gallon Sears air compressor so folks would have some idea what they looked like. No joy. I did find an image of a reasonably current 33 gallon tank Sears / Craftsman air compressor to give you some idea of the size.
Now, to Royce’s Sears compressor problem.
Off hand, Royce, we would say that you’ve used a too-small gauge wire extension cord, and you are under-powering the motor. If you think about the extension cord as a water hose, and if that the water hose was 1/8″ I.D. versus 1/2″ I.D., the different hoses will flow different volumes of water. The 1/8″ hose will restrict the flow as compared to the 1/2″ hose, and if you need a lot of flow quickly, the 1/8″ hose may not be big enough.
Back to the compressor motor. An electric motor needs a minimum amount of “power-flow” to run and even more power (called inrush current) to start. If the “hose” through which you are supplying the motor with power is too small (too light a gauge wire) then there isn’t enough power fast enough to start the motor and get it running.
Hence the motor sound change we believe.
Worse, if you continue to power the compressor motor with too small a power line you may actually damage the compressor motor.
Try plugging the compressor cord directly into a wall socket fed by a 20 amp circuit breaker, and see if that makes a difference.