I couldn't find much info on your machine but I did find a supplier for the compressor.
LINK . At least you have a source if you can find someone willing to install it. Dunno why you are experiencing poor compressor life. Is cleaning condenser coil on your maintenance schedule?
From their site:
"Mitsubishi -
A well built chiller product found on many EDM machines and other Mitsubishi machining centers. With variable frequency drive applied to the compressor it can sometimes be difficult for many refrigeration mechanics to trouble-shoot. Look to your machine tool control "types" for an assist when you bring in the refrigeration tech. Many of the Mitsubishi chiller designs are "in-line" which means the chiller contains the refrigeration circuit but the fluid media circulating pump is located near the heat source. This variable frequency design allows for the cooling load to be adjusted because the compressor is allowed to slow down, giving a "throttle effect" that might otherwise be obtained in refrigeration by the expansion device. These chillers utilize R-22, a three (3) phase hermetic compressor (with "Frequol Drive"), capillary tube expansion device, and valves re-directing fluid to compliment the "throttling" of heat removal."
JR