LG heat pump bearing fluting

[Thomas]

If anyone has an LG heat pump and the head unit sounds like a turbo spooling up your may want to change the two 608zz bearings in the fan motor. The bearings suffer from the circulating currents in the rotor caused by the inverter (not getting more technical than that) which leaves a rail road like track around the inner and outer races. I tried to get a picture but the bearings are so small it's really hard to see so I attached more detailed stock photo. This is a 12K unit and this is the second set of bearings I've installed since 2013.

 

[RobinHood]

Isn’t that amazing.

How about using ceramic ball bearings instead of steel ones?

 

[Johnwa]

That’s interesting, Coincidentally in the video linked in
Post in thread 'Tool Post Grinder'
https://canadianhobbymetalworkers.com/threads/tool-post-grinder.4327/post-58917
The bearing is held in a rubber cup. His repair was to replace it with a brass bushing. Down in the comments section he mentions replacing the brass with Delrin. I assume it was to avoid circulating currents.

 

[Thomas]

Yes ceramic bearings solve the circulating current problem, we actually install a lot of ceramic coated bearings in electric motors as well as grounding brushes in our shop. With my heat pump I always have premium grade 608zz available and it only takes me 15 minutes to swap them out.