Crane Nuclear, Inc.

Binish Praful Desai

Martin Joseph Dowling

George Fox Lang

Louis Ricciuti, Jr

Briefly stated the motor speed monitor includes a method of determining a shaft speed of a motor by using an electrical signature of the motor. The method includes: (a) sensing an electrical current supplied to the motor to generate a current sensor output signal for at least one electrical phase of the motor; (b) demodulating the current sensor output signal for a predetermined time interval to obtain an instantaneous amplitude of the electrical current signal; (c) generating a frequency spectrum of the instantaneous current amplitude; (d) finding at least one spectral peak of the instantaneous current amplitude frequency spectrum within a predetermined shaft frequency sideband range; (e) estimating a shaft frequency from the at least one spectral peak and converting the shaft frequency to shaft speed.

Apparatus and method for determining shaft speed of a motor

A method of detecting broken rotor bars including sensing currents applied to the motor, converting the senses signals to digital data signals, and storing the digital data signals. A processor evaluates the digital data to provide a current signal spectrum at various selected sidebands. Sideband peaks having an amplitude within a predetermined value are identified, indicating potential motor problems or developing problems, including winding faults and broken rotor bars. Advanced signal processing techniques are used to further evaluate stored data and to provide trending information.

Motor condition and performance analyzer

A motor performance analyzer senses currents and voltages applied to the motor, converts the sensed signals to digital data signals, and stores the digital data signals. The analyzer includes a processor for evaluating and comparing the digital data signals to predetermined values for voltage and current of the motor to determine and check for the correct placement of the current and voltage probes along corresponding phases of the motor. The analyzer also includes &lsqb;and&rsqb; a display for alerting a user or technician to potential motor problems, or to developing problems, including winding faults and broken rotor bars. &lsqb;Advanced signal processing techniques are used to further evaluate stored data and to provide trending information.&rsqb;

Method of monitoring placement of voltage/current probes on motors

A motor performance analyzer senses currents and voltages applied to the motor, converts the sensed signals to digital data signals, and stores the digital data signals. The analyzer includes a processor for evaluating the digital data and a display for alerting a user or technician to potential motor problems, or to developing problems, including winding faults and broken rotor bars. Advanced signal processing techniques are used to further evaluate stored data and to provide trending information.

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Norristown, PA, United States of America

Binish Praful Desai