That trapped air adds to the load the compressor motor experiences on start up, and that additional load may be enough to force the motor into pulling too many amps and popping the breaker, or blowing the fuse.
What are the things on the compressor to check when the air compressor trips the breaker or fuse on restart? Did the unloader valve work? Sometimes the unloader valve fails, and as a result, some compressed air is trapped over the cylinder piston. If for some reason the motor cannot start, it will continue to draw power, and may pull enough amperage to exceed the capacity of breaker or fuse and as a result the compressor trips the breaker or fuse on restart. Larger compressor motors require a “kick start” to get going, as there is not enough power in the circuit to to feed what the compressor motor needs on start up, and that’s called the “inrush current”. If a particular compressor motor does not have a start capacitor, often that’s a small, sub-fractional motor, and there is sufficient current in the electricity flow to kick that motor into turning. When the air compressor tank is drained down to the cut in pressure level, the pressure switch reacts to the drop in tank pressure, it trips to “passing” (as in, the current now flows to the compressor motor) and the compressor should start and run until the compressor tank pressure has reached the normal cut out pressure setting, at which time the compressor should stop and wait for the tank air pressure to drop to the cut in pressure level again.Īt the cut in pressure setting the the current will flow first through the pressure switch and then through the motor start circuit, and for a huge number of different makes and models of air compressor, the current then flows to a start capacitor.
#OLDER SEARS 240 AIR COMPRESSOR 3.5 HP 240 VOLT HOW TO#
what are the compressor components involved and how to check them? What’s happening when a compressor trips the breaker / fuse on restart? what needs to be checked on the air compressor when that happens? what’s happening when the compressor trips the breaker or burns the fuse on restart? If it’s a fuse in the circuit instead of a breaker, when attempting to restart, the compressor blows the fuse. Then, and as the pressure in the tank drops to the cut in pressure setting, rather than the compressor starting to rebuild the air in the tank, when it tries, the compressor trips the breaker on restart. The air tool ramps up nicely and is working well.