Eaton Corporation

Michael A Urbassik

Michael E Bauer

Bonne W Posma

Anthony J Davis

A reversible DC motor drive includes a DC/DC converter having a DC input, a first output having a first pulsed DC voltage and first DC voltage value, a second output having a second pulsed DC voltage and second DC voltage value, and a third output having a third pulsed DC voltage and third DC voltage value. The first and second outputs are adapted for electrical interconnection with armature terminals of a DC motor, and the third output is adapted for electrical interconnection with a field terminal of the motor. A microprocessor routine calculates motor speed from the motor armature voltage, field current and armature current. An outer control loop for motor speed and two separately controllable inner control loops for armature and field current control the DC/DC converter responsive to the calculated motor speed and a speed reference in order to independently control the three DC voltage values.

Reversible DC motor drive including a DC/DC converter and four quadrant DC/DC controller

A control circuit for an overhead crane motor includes a low supply voltage monitor to disconnect the motor from the control circuit and ensure brakes engage in the event of interruption of power supplied to the crane. A sensor circuit detects whether voltage supplied to the control circuit drops below a predefined threshold level which is greater than a voltage magnitude produced by the motorN operating in a regenerative mode during a power interruption. A switching circuit responds to sensing supply voltage below the threshold level by disconnecting electrical current to a relay coil which causes contacts to open which result in the motor being electrically disconnected from the control circuit. As a result of that disconnection, voltage produced by the motor operating in a regenerative mode does not inhibit electrically controlled mechanical brakes from engaging.

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Menomonee Falls, WI, United States of America

Michael A Urbassik