# Compressor trip issue fixed



## Mike335 (Sep 5, 2018)

So I was unable to find or buy new points for my Craftsman 921153101 1HP compressor, or even find the points or associated centrifugal switch in a parts list after spending hours searching for them online and another half hour talking on the phone with a Sears tech support guy. See my previous post: https://www.powerequipmentforum.com/forum/7-air-compressor-forum/21274-compressor-trips-breaker.html

After taking the shroud off of the compressor and looking at the points, I had concluded that the points were the likely issue causing the instant breaker trip when I attempted to start the compressor. The points are attached to a ring that mounts to the fan end of the motor under the fan and centrifugal switch (see attached photos). The centrifugal switch transfers current from the start capacitor to the run capacitor once the motor is spinning at operating RPM. When I pulled the retaining circlip and removed the fan, I found that the single screw that fixes the centrifugal switch on the motor switch was loose so that the switch assembly could slide outward on the shaft until the plastic fan stopped it. This may have caused the short that welded the points open. 

Since I could get no help from Sears, I took a second look at the points to see if I could fix the points assembly rather than replace it. I took a Stanley razor knife and forced it between the back of the upper point where it had arc-welded itself to the metal piece above it. Rocking the knife back and forth with the metal against the floor, I was able to cut through the filament of metal that had melted to the outer point and separate it from the metal above it without breaking the ring. I then took a fingernail file and used it to smooth the metal, remove the remnant glob of melted metal, and clean between the points. Now the points could open and close again. When I mounted the points and the centrifugal switch and tested the compressor it worked perfectly. There is a springy circular piece of metal in the center of the points assembly around the shaft that the centrifugal switch pushes against until the motor spins up causing the centrifugal switch to pull the black pressure ring back off of the points assembly so that the points open and power is transferred to the run capacitor. Since the points were welded open, current was either shorting to ground or to the run capacitor so that the start capacitor which is designed to accept the brief power surge required to start the motor spinning would not engage at the start. This was immediately tripping the breaker on the circuit I was plugging the compressor into. Anyway, I was able to get this handy tool working again without spending any money or waiting for parts. Hopefully it will continue to work for a long time.


----------

