Browse Prior Art Database

Multimode Control of DC Series Motor

IP.com Disclosure Number: IPCOM000094627D
Original Publication Date: 1965-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Fredriksen, TR: AUTHOR

Abstract

A DC series motor can be operated as a series motor, a shunt motor and be dynamically braked.

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Multimode Control of DC Series Motor

A DC series motor can be operated as a series motor, a shunt motor and be dynamically braked.

A DC series motor is provided with CW and CCW rotation field windings, an off-direction switch 1, a PNP transistor, a resistor, a zener diode. Two additional switches 2 and 3 are connected such that the motor operates as a series motor when the direction switch 1 is on and switches 2 and 3 are open. This connection provides high torque and acceleration to reach a high speed.

Closure of switch 3 causes dynamic braking to a low speed. Such is by the partial shunting of the armature by the moderately conducting transistor which, in turn, is controlled by the armature back EMF causing the zener diode to function. When the armature voltage drops to the zener value, the armature and field voltage are essentially constant so that the motor effectively operates as a shunt motor. Closure of switch 2 shunts the zener diode so that the transistor conducts heavily to effectively shunt the armature. This causes dynamic braking from slow speed to a near stop. Armature cogging produces the final stopping force.

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