See What's Inside a Scroll Compressor

We cut open a burned-out scroll compressor and see what's inside. We see how scroll compressors differ from reciprocating compressors and see what might have contributed to this one's failure.
This scroll compressor received the notorious "not pumping" diagnosis. When we opened the compressor, we saw that there was grit all over the place. Removing the top scroll caused little pieces of metal to fall everywhere, but the scroll itself appeared to be in decent condition. The bottom scroll also appeared to be in fair condition, but there was some mechanical wear on the copper plating. There was major scoring on some of the unidentified parts that had come off.
It appeared as though the compressor had a winding burnout, as there appeared to be acidic oil on the inside. Further investigation of the call notes indicated that an acid test was performed and came back positive, confirming our suspicion of burnout.
The pieces throughout the system likely came from the windings and some other parts of the system, which probably caused the motor to short out. So, there was a combination of burnout and mechanical failure.
The terminals on a scroll compressor work the same way as they do in a reciprocating compressor, but these scroll compressor terminals were highly susceptible to melting given the type of failure we saw.
Eventually, we'd like to cut the compressor even further to look at a cross-section of it. However, since we took the scrolls out, you can see how the top scroll has an orbiting action that results in oscillation between the scrolls, which is how the compression happens. The gas goes in through a large port on the side and gets trapped between the two scrolls, becoming smaller and smaller in volume as the top scroll moves. Then, the gas gets discharged through the center.
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[@jeffb8437]

Very interesting. Thanks

[@justin0957]

No compressors where harmed in the making of this video, except the compressor that was harmed in this video

[@rcinfla9017]

The busted part is called the 'Oldham ring'. Its purpose is to keep the bottom orbiting scroll from rotating around as it is driven by motor 'wobulator' cam shaft. If a heavy slug of liquid refrigerant and/or oil gets between the scrolls it can push the orbiting scroll off position with a lot of lateral force that can break the Oldham ring. This happens if lateral force occurs quickly, not giving enough time for scroll plates to separate to relieve the pressure from liquid. I think it takes a lot of liquid to break Oldham ring, like if someone pre-charges with liquid refrigerant dumped into low side port then immediately turns on compressor. Perhaps a less than half second power glitch that causes a sudden motor reversal might also break it. Another reason for breakage is top motor bearing wear causing wobble in motor shaft. Motor top bushing wear can also allow rotor to scrape against motor stator iron laminate core creating heat and possibly sparks that fry the motor stator windings insulation.

[@consensuallycasual2697]

Thanks Bryan!

[@UlisesPalacios]

That’s the oldham coupling. I haven’t seen that. Awesome.

[@jeffb8437]

Ulises Palacios nothing good about old ham

[@UlisesPalacios]

Jeff Blanton lol 😂

[@mollypenderson2851]

Nice video

[@yenjoveerojo9440]

I need to see the top parts

[@Markflyrod]

At 5:45 it looks like that could be step wear on the scroll. If it is, that is caused by high compression ratio.

[@ananth218Canada]

i wonder if someone ran it in the opposite direction...