See What’s Inside a Reciprocating Compressor

We notice a tag that has started melting off, and it says that the compressor needs a start assist device (hard start kit).

The motor is at the top of the compressor, and the actual compression happens at the bottom of the compressor. The suction line goes straight into the shell, and there’s a hole that extends past the motor.

Before we get in too deep, we bring out our meter leads and confirm that the compressor has indeed shorted to ground. When we cut into the compressor further, we realize that the oil isn’t too pungent (such as from acid), but there are a lot of metal shavings in the compressor and mechanical wear around the windings. The “Fusite” appears to be in decent condition; that’s the seal that holds the terminals on the compressor. However, the motor windings appear to be completely cooked. The thermal overload has been immersed in refrigerant and oil, and the windings appear to be in rough condition.

When we see the compressor in its open state, we can see how the suction gas cools the motor in the head of the compressor before the gas gets compressed.

The actual compressor is in decent condition; the oil is also relatively clean. However, we hear a weird clunking noise on the stator side. The valve plate, which has suction, bypass, and discharge valves, is in solid condition.

Bristol compressors have pistons that both move when the crankshaft goes one way, and only one piston moves when the crankshaft spins the other way. However, the pistons don’t want to move on one side, and there is no copper plating, which is a bit odd.

So, the main problems were the cooked motor windings and the effects of mechanical wear.