Changes In Pump Vibration Levels Caused By The Misalignment Of Different Style Couplings

Abstract

Unacceptable pump vibrations are sometimes caused by the misalignment of the motor to the pump. Pump vibration increases due to misalignment is dependent on the amount of misalignment and the type of coupling used. The results and conclusions are reported of a test program that studied the effects that increasing amounts of parallel misalignment had upon vibration levels using different style couplings. The test setup used during the program and the test procedure followed to assure equal testing conditions for all the couplings are described. A total of nine different style couplings were tested. One metal coupling was able to withstand a large amount of misalignment without causing a significant increase in the pump vibration level. Couplings using an elastomeric type insert tend not to increase the pump vibration levels when misaligned, but do so at the cost of their useful life. Unbalance appears to be more of a problem with elastomeric couplings than with metal type couplings.