View Full Version : Copeland Semi-hermetic compressor failure study class

19-03-2011, 03:51 AM
Good evening to everyone.
Im taking a course on Copeland semi-hermetic compressor failures. It includes the de-assembly of several dead compressors. Right know we are looking at a case involving the revolving rotor cutting thorugh the windings due to bearing failure. The compressors is a 3DS , three cylinder unit. As far as I can see, there are three bearings supporting the crankshaft: frontal side, middle and back side. Ive noticed that the middle bearing is not completely smooth, but rather has some kind of pattern formed on its surface: it looks like an "U". The instructor said that this bushing must be located in such a way that the crankshaft rests on this "U", whose function is to serve as an oil reservoir. From here, the rotating crankshaft picks oil up and carries it upward in order to lubricate the upper part of the bushing. Is this right ? There is a classmate who believes that the bushing must be located in such a way that the upper part of the crankshaft makes contact with the inverted "U", so that the flow of oil that comes out of the crankshaft orificies runs down through the "legs" of the inverted "U" pattern towards the lower part of the bearing. Does anynone know what is the correct positioning of this bearing ?
Thank you.

19-03-2011, 02:03 PM
When i used to rebuild i remember we used to fit teflon coated bearings with the hole at the bottom to drain back into the sump. Just out of interest when you get to the Copeland D8 range they have an oil feed to the front and back of the crankshaft via a 3/8 pipe to the middle of the two centre bearings. The D3 range shares a lot with the Prestcold 'R' Range and usually older ones still have phosphor broze bearings

Hope this helps

19-03-2011, 07:41 PM
Hi i always taught my students to put the groved side of the bearings on top of the crankshaft, because when the compressor stops those groves act as reservoir and as the compressor is in stationary position, the oil drains down to the bottom of the bearing and lubricates it slowly , so its not dry when compressor starts up again.