American Standard Inc.

Trane International Inc.

American Standard International Inc.

Michael W Murry

Joel C VanderZee

Matthew A Shepeck

Thomas J Clanin

Paul C Rentmeester

Robert E Krocker

Dennis Lee Justin

Chad J Kurszewski

A signal analyzer for calculating the power consumption and power factor of a three-phase power system driving a motor includes logic that determines whether the analyzer's own input terminals are wired in a proper or inverted manner. To do this, the signal analyzer observes a pattern of zero crossing slope values of the three line-to-line voltages of the three-phase power system and observes a pattern of zero crossing slope values of the current in the three power lines. The analyzer also compares the slope of a voltage signal as the signal passes through zero volts and the sign of a corresponding current signal that exists as the voltage signal crosses zero volts. Based on the observed voltage and current patterns and the voltage-to-current relationships, the analyzer can positively identify which of a plurality of inputs or signal wires are inverted.

Method of recognizing signal mis-wiring of a three-phase circuit

A motor starter. The motor starter comprises a motor; start, run, shorting and transition contactors operably associated with the motor; and run, start, shorting and transition auxiliary contactors. The transition auxiliary contactor operably controls the operation of a shorting contactor, and the shorting auxiliary operatively controls the operation of the run contactor.

Method of controlling three phase motor starting sequence

An apparatus for detecting faults in a starter circuit adapted to connect a multi-phase electrical motor to a power supply. The motor has at least one winding per phase, each of which terminates in at least one terminal. The starter circuit includes a plurality of contactors which are energizable to connect the motor windings to the power source. The fault detection apparatus comprises a current sensor for sensing the current flowing through the windings of each phase and responsively producing respective winding current signals. A diagnostic module controllably energizes the contactors, samples for the presence and absence of the winding current signals while different ones of the contactors are energized to detect faults in the contactors, and responsively produces fault signals.

Starter contact integrity test

An apparatus and method for protecting an induction motor from momentary power loss in a three-phase, alternating current, power supply. The apparatus includes a circuit for detecting when the motor switches from a mode of operation as a motor to a mode of operation as a generator, and a microprocessor connected to the detector to receive the detection of a switch in mode of operation, and for generating a fault disconnect signal in response thereto to initiate disconnecting the motor from the power source. The method includes the steps of detecting when the motor switches from a mode of operation as a motor to a mode of operation as a generator and generating a fault disconnect signal in response thereto to initiate disconnecting the motor from the power source. The apparatus and method provide for robustness of the fault detection data, and for avoiding false detections of momentary power loss.

Apparatus and method for protecting induction motors from momentary

The determination as to whether an operational compressor in a multiple-screw compressor water chiller is fully loaded is made by sending a relatively long duration test pulse to the load solenoid of the compressor. If the compressor is fully loaded, no measurable change in the current drawn by the compressor motor will be measured since no slide valve movement will have occurred and no additional load will have been placed on the compressor. If, however, the compressor is not fully loaded at the time the test pulse is sent, the compressor slide valve will move to load the compressor to an extent such that a reliably measurable change in compressor motor current draw occurs.

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Onalaska, WI, United States of America

Michael W Murry