Sunday, August 13, 2017

Taking Apart a Refrigerator Compressor

One day I was watching a Huell Howser episode on refrigerator recycling.  I was curious about the compressor part for two reasons; 1. I was considering building another bicycle powered compressor for a full fledged bicycle foundry vegetable oil burner, and 2. I'd read during a research project that they use permanent magnet brushless motors in applications like this and wanted to build a generator with them (also bicycle powered of course). 
Immediately after watching the episode, I went for a walk and conveniently, found a refrigerator next to the dumpster.  I jumped at this amazingly obvious scrap alchemy opportunity.  I noticed somebody else had already cut the copper pipes that would contain the freon, so I was already exempt from having to deal with that issue.  I went out with some tools and within a matter of 10 minutes had taken off the compressor and also the cooling fan.
Let's take it apart!

I had to use a hacksaw since these things are completely sealed and welded together.  I went around the whole circumference lightly to cut a groove before penetrating the interior (to avoid accidentally mismatching the cut) of course I couldn't just saw straight through since there's stuff inside.  The only way I was able to clamp it was between the chuck and tailstock on my lathe.  I made sure to put some paper down to prevent getting metal dust on my lathe ways.
After a lot of sawing, it is open!
Taking the motor assembly out which was initially resting on springs in the bottom for vibration dampening.  The whole container must've been filled with oil because this thing dripped for a while prior to cutting.
The bent tube on the end appears to be an oil intake to lubricate the motor's bearing surfaces.  This part spins eccentrically since it connected to the piston rod.
My best guess was that the white plastic thing was a reservoir for the refrigerant.
After unscrewing another tank looking thing.  I noticed that while the body of the compressor is a symmetric iron casting, it looks like it could've been machined for one of 2 different configurations; the tank on top or on the bottom as it is here.
Pulling apart the motor.  To my dismay, there were no such permanent magnets to be found in here, just a regular motor.  The part that intrgued me was the absence of ball bearings.  Being permanantly lubricated and sealed, I guess they didn't need them.
More pics of the final motor disassembly coming soon.

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