Integrated electric motor monitor

Abstract

A method monitors an operational condition of an electric motor, and stores in a memory device general trend, prognostic, diagnostic, and hazardous event information indicative of the motor's operational condition. The method includes the steps of sensing characteristics indicative of the operational condition of the electric motor, such as vibration, temperature, magnetic flux, and the voltages applied to the motor's windings, and generating sensor signals related to the sensed characteristics. Upon the occurrence of a first circumstance, such when measurements of the motor's speed, winding temperature, and voltage, indicate that the motor is operating within its normal load profile, prognostic information is extracted from the sensor signals. The prognostic information provides a profile of the motor's operational condition over time without the influences of fluctuating loads, temperature, and voltage. Upon the occurrence of a second circumstance, such as when the motor's load factor is within a load factor range that is most common for the motor, diagnostic information is extracted from the sensor signals. The diagnostic information indicates the motor's operational condition when it is operating within its most common load zone. Upon occurrence of a third circumstance, such as an indication that the motor is operating abnormally, hazardous event information is extracted from the sensor signals and stored. The hazardous event information indicates the motor's condition at the time that a hazardous event, or fault, occurred. The general trend information is measured and stored at regular intervals to determine short- and long-term operational trends over time.