Oilers/Plant Tenders (HHC) Civil Service Practice Exam

In a centrifugal refrigeration compressor, which parts specifically require lubrication?

1. The rotor and condenser

2. The rotor and thrust bearing

3. The pump and motor bearings

4. The compressor's cylinder and piston

The correct answer is: The rotor and thrust bearing

In a centrifugal refrigeration compressor, lubrication is critical for specific components to ensure proper operation and longevity of the system. The rotor, which is a key component that has to rotate at high speeds, requires lubrication to minimize friction and wear, allowing it to operate efficiently. The thrust bearing also needs to be lubricated since it supports the rotor and absorbs axial loads created during operation. Without adequate lubrication in these areas, excessive wear, overheating, and potential failure can occur, which would impair the performance of the refrigeration system. While the other components mentioned in the other options may require some form of maintenance or lubrication, they are not as crucial as the rotor and thrust bearing in terms of the centrifugal refrigeration compressor's fundamental operation. The cylinder and piston relate more to reciprocating compressors, while the pump and motor bearings may not be the core focus in a centrifugal design.