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View Full Version : derailed by an ice maker



darryl
03-24-2019, 01:52 AM
Ok, I don't make a habit of taking compressors apart, but I decided to hack this one. Ice maker on the side of the road, cord gone. I figured what the heck, I could use the finned radiator regardless if the machine was any good. I saw the little r134 filler tube had been bent and almost broken off so I figured there's no gas left to escape. That's when I decided I'm going to open this can. As I'm checking it out I got the motor to hum but not start, so off came the head. You know the routine- drain the oil from any tube that it will come out of, then using a cloth to catch drips you still get oil all over the place while you band saw the top away. And there's the guts.

There sits a cast iron single cylinder pump. The first thing I notice after that was bits of string loosely laying around. One piece was wedged between the armature and the field- with a bit of rotating the motor shaft back and forth I got it freed. Everything turns freely now. This is the string that is supposed to be binding the wiring together, but it's all loose. There had to be 40 or 50 ends in there, and many pieces were less than two inches long. Something must have gone wrong during the automatic tying operation, and quality control missed it. Hmm.

At any rate the pump works fine. It pulls a pretty good vacuum, and there's good pressure on the output. The piston looks perfect for as much as I can see of it. No scoring at all, no detectable play, virtually no friction. The name plate on the ice maker says 1.7 amps draw, and 2.2 amps when the ice is being cycled into the hopper. So not a very powerful motor, nor a very high flow rate. You wouldn't be running your air sander from it, let's put it that way. The name plate also says design pressure of 88 psi and high pressure of 290 psi.

From the amount of oil that I drained it is apparent that only the end of the motor shaft would have dipped into it. This is interesting- it appears that lubing everything is by sucking oil up through the motor shaft and bearing, then on to the con rod big end, probably through the con rod to the wrist pin and cylinder walls. The pump sits at the top and I can see no other way that it would get lubed at all.

In any event, the discovery fun is gone now and I have this pump that I can use for something.

Noitoen
03-24-2019, 04:00 AM
The hole in the shaft should be a little off center and this scoops the oil as it rotates acting as a simple screw pump

CCWKen
03-24-2019, 07:26 AM
The problem is it's not any good outside of its environment. The pump and motor typically need the oil to survive all but the shortest run.

Tom S
03-24-2019, 08:37 AM
There's a small amount of oil that gets carried through the entire system with the refrigerant itself. The suction/input side of the compressor is usually located near the top of the can, so that some oil gets sprayed around from above the piston and motor. The motor shaft also has an oil pickup that pulls some oil out of the sump in the bottom to keep everything properly lubricated.

Yeah, not a lot of volume being put out by those little pistons. It's more about pressure than about flow at that size.