Leesona Corporation

John Brown Inc.

Kenneth A Benjamin

Charles W Brouwer

This relates to the provision of a stall shutdown circuit for a brushless direct current motor wherein energization of the windings of the stator of the motor is controlled by transistors. By providing a stall shutdown circuit for shutting down power to the transistors when a stall condition exists, the capacity of the power supply transistor may be reduced to one-third of that presently required, thereby greatly reducing the cost of the motor. The brushless direct current motor utilizing the stall shutdown circuit of the present invention is particularly useful in a textile machine such as a take-up device where it is necessary to stop a spindle to doff and don yarn packages.

Stall protection circuit for brushless motor control

This invention relates to a take-up machine utilized in conjunction with the production of fiber or yarn wherein the product fiber or yarn, as it is produced, is wound onto spools or tubes. A control is provided for varying the speed of an electric motor which drives a spindle on which the tube or spool is mounted. This control is actuated by the position of a compensator arm which is connected to a core of a linear voltage differential transformer which, in turn, controls current flow through an NPN power transistor. The power transistor, in turn, controls current flow through a rectifier having one circuit for each of three windings of a three-phase AC motor, thereby controlling the speed of rotation of the motor.

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Greensboro, NC, United States of America

Kenneth A Benjamin