black max compressor stops building pressure

i have an 80 gal black max compressor: runs fine and builds pressure until it get to 25 lbs. at this point the motor/pump starts to slow down--then about 10 to 15 seconds later it will start running normal. the slowing down and running normal keeps happening.

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Bill says...

Howdy. First thing, please check and see what else is operating on the same electrical circuit that is powering your compressor. Make sure all other current draws are off, and see if that makes a difference.

Your compressor motor is slowing because it may have a supply power drop, or something in the compressor air circuit is adding load to the motor, and this slows it down.

If air cannot flow easily from the pistons into the tank (valve in pump or check valve at the tank) the back pressure would increase the load on, and slow, the motor, and as that load decreased the motor would speed up.

It could also be a failing motor.

Post again after you have done some checks, will you?

Cheers,

Bill