Abstract: A fault control protects a pump-motor assembly from monitored faults. The pump-motor assembly includes an electrical motor mechanically coupled to a pump. The fault control determines a speed of the motor. If the speed is determined to be less than a minimum speed, the fault control generates a fault signal to affect the operation of the motor. The fault control can also determine if a phase of the power provided to the motor is missing based on vibrations sensed by a vibration transducer. The fault control can also determine temperature faults based on signals from two thermocouples, including determination of loss of inlet or discharge flow.

Abstract: A method to detect gulping in a pump driven by a motor drive to pump a liquid includes: determining a value of a work indicator corresponding to work performed by a pump pumping a liquid; comparing the value to a first threshold; changing a value of a tracking variable by a first amount if the value of the work indicator is below the threshold; changing the value of the tracking variable by a second amount if the value of the work indicator is above the threshold, wherein the first amount and the second amount have opposite signs; and determining that a gulping event occurred if an absolute value of the tracking variable is larger than an absolute value of a second threshold.

Abstract: A fault control protects a pump-motor assembly from monitored faults. The pump-motor assembly includes an electrical motor mechanically coupled to a pump. The fault control determines a speed of the motor. If the speed is determined to be less than a minimum speed, the fault control generates a fault signal to affect the operation of the motor. The fault control can also determine if a phase of the power provided to the motor is missing based on vibrations sensed by a vibration transducer. The fault control can also determine temperature faults based on signals from two thermocouples, including determination of loss of inlet or discharge flow.