Patent ID: 7954371

Claim:
A method of monitoring the condition of a pump the method comprising the steps of: generating a predetermined test condition in the pump, comprising generating and sustaining for a substantial period of time an abnormal pump speed outside a range of normal pump operation speed whereby the pump is subject to an increased stress as compared with normal operating stresses, thereby causing a reduction in clearance between a rotor and a stator of the pump; and obtaining signals indicative of an amount of the clearance between the rotor and the stator of the pump during a period in which the test condition is present, wherein the signals are derived from a current consumed by a motor driving the rotor of the pump, wherein the reduction in clearance is caused by the steps of causing a predetermined reduction in rotor rotation speed from a selected speed for a predetermined period of time and then causing a predetermined increase in rotor rotation speed above the selected speed for a predetermined period of time.