I gave my son a 220V 2 HP. air compressor and it has always run well.
The compressor is in his unheated garage which is about with a
temperature of around 0 degrees F. The motor trys to turn and trips
the breaker because it does not have enough torque. With the belt
removed the motor runs fine. Turning the flywheel by hand does not
seem abnormal. Could this be a faulty capacitor on the motor or has
the compressor casing shrink a bit because of the cold and there is
not enough clearence for the pistons. How can a capacitor be checked
to see if it is all right? Putting up walls in his basement and we
really need the compressor to run the framing nailer Thanks.
If the motor runs without the belt on the cap is ok. There is a blow by
valve that lets the motor spin the compressor up without working against the
air pressure until it gets a little head up. Make sure the valve is working
freely. Try this - drain the tank and leave the petcock on the tank open.
Then try to start the compressor. It's not the same as the pressure relief
valve, but it might give you an indication if the valve is the culprit.
I agree. The line between the outlet of the compressor and the tank needs
to be de-pressurized when the motor starts, otherwise the motor will pull
too many amps and trip the breaker.
I had this happen on my old 2 HP unit. The check valve had a spring which
rusted, and the result was the line did not de-pressurize after the unit
turned off. In this case I merely had to replace the spring.
Look for a 1/8in size line coming off the compressor discharge and see where
the de-pressurization device is located.
I have a compressor that had this problem. I think it is a typical
problem due to the high torque required when the oil is cold and the
V-belt is stiff. I changed the belt from an old style V-belt to a
thinner, more flexible one and after that I could put a larger pully on
the motor and still get it to start in a cold garage. A cold, stiff
V-belt sucks a lot of power. Also, the line from the breaker panel to
the garage is usually quite long and in a 115V line, probably not the
heaviest gauge. Since you have a 220 V line, I would think that that
might not be as big a problem, especially with just a 2 HP motor. As
Mike said above, the pressure relief valve could cause the problem.
When I had the problem, I often held the valve open manually (not all
can do this) and that would allow the motor to come up to speed
unloaded and warm the parts up so it would run normally. Not the best
solution I will admit.
Agreed - I've got an oil-lubed compressor that complains a lot this time of
year unless I switch out the oil for a lighter grade. Just don't forget to
put something a tad thicker in when the weather warms up again.
Along with all the others, a side thought... Make sure it's getting
the power it needs from your outlet. I found that one outlet in my
garage is just far enough away from the breaker panel that the
compressor won't start reliably, but a different outlet (wiring?
connections? outlet? who knows) works just fine.
air compressors that use oil for lube need a thin oil if run outside in an
unheated area. I service all makes and models up to and including 400HP
units. You need a thin 10 weight non detergetn oil in the unit. The oil is
thickening up and preventing the unit from running. If the unit is still
having problems look at the tank check. Graingers sells them in various
styles. The most common one is a 6X209.
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