Browse Prior Art Database

Motor Driver

IP.com Disclosure Number: IPCOM000097510D
Original Publication Date: 1961-Jan-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Bryson, BL: AUTHOR

Abstract

The bi-directional motor controller employs semiconductor devices. It is adapted to suppress semiconductor leakage current when motor rotation is changed from one direction to the other.

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Motor Driver

The bi-directional motor controller employs semiconductor devices. It is adapted to suppress semiconductor leakage current when motor rotation is changed from one direction to the other.

A D. C. motor 10 is connected across the diagonal of a bridge circuit 12 employing controlled rectifiers 14, 16, 18 and 20. The rectifiers 14 and 16 are gated on and off together. Similarly, the rectifiers 18 and 20 are gated on and off together. Transistor switch 22 connects the bridge between a power supply 24 and a reference point. When switch 22 and diametrically opposite rectifiers are turned on, the motor rotates in one direction or the other according to the rectifiers turned on. When the rectifiers are turned off and a reset pulse applied to the switch, the leakage current of 22 is normally sufficient to maintain the previously operated rectifiers in the conducting condition.

Turnon of the other set of rectifiers connects the supply directly to ground. Resistor 28 and supply 26, however, divert the leakage current of 22 away from the rectifiers. Supply 26 is also more negative than supply 24 and ensures turnoff of all rectifiers. The use of resistor 28 and supply 26 ensures that rapid switching of the rotational directional of the motor does not connect the supply 24 to ground. This is because the previously operated rectifiers are always in the nonconducting condition when the other rectifiers are turned on.

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