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Stepping Motor Braking System

IP.com Disclosure Number: IPCOM000091422D
Original Publication Date: 1968-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Wallis, CN: AUTHOR

Abstract

This system prevents a stepping motor from hunting before the rotor settles at rest. The stator of a stepping motor has four Poles N, E, S, and W. Each pole has a winding with a normally open switch and a capacitor connected across the winding. The rotor is shown in two positions. The rotor is caused to rotate in a clockwise direction by energizing the next adjacent pole in a clockwise direction and deenergizing the pole on the counterclockwise side of the rotor. If the rotor is to be stopped in alignment with pole N, braking torque is applied when it is past pole S and is in the SW position. This braking torque is achieved by maintaining pole S energized and energizing pole W. Such provide a resultant field in the SW direction which slows down the speed of the rotation of the rotor.

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Stepping Motor Braking System

This system prevents a stepping motor from hunting before the rotor settles at rest. The stator of a stepping motor has four Poles N, E, S, and W. Each pole has a winding with a normally open switch and a capacitor connected across the winding. The rotor is shown in two positions. The rotor is caused to rotate in a clockwise direction by energizing the next adjacent pole in a clockwise direction and deenergizing the pole on the counterclockwise side of the rotor. If the rotor is to be stopped in alignment with pole N, braking torque is applied when it is past pole S and is in the SW position. This braking torque is achieved by maintaining pole S energized and energizing pole W. Such provide a resultant field in the SW direction which slows down the speed of the rotation of the rotor. When the rotor is past pole W, pole N is energized and the resultant field is in the NW direction. This field stops the rotor in the vicinity of pole N. If, at this time the normally open switches are closed, capacitors act in the winding circuits of poles E and W to effectively damp any emf generated in these poles by the oscillation of the rotor about pole N.

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