Vibration of Deriaz Pumps at Dos Amigos Pumping Plant

Abstract

Severe vibration problems were encountered during initial operation of large Deriaz pumps. This paper describes those problems, the alternative solutions available, and the corrective action taken. Transient shaft vibrations prevented normal pump shutdown operation, when severe counter-rotational whirl occurred as the shaft speed decreased. Vibration at low blade angles preclude operation below half the rated flow. High intake water levels led to rotational shaft whirl in the normal operating range. Subsequent field testing evaluated various possible sources of vibration excitation, and verified the remedy of air injection into the headcover.