Browse Prior Art Database

Gated Fixed Reference Oscillator Stepping Motor Speed Control

IP.com Disclosure Number: IPCOM000075689D
Original Publication Date: 1971-Oct-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Wallace, LJ: AUTHOR

Abstract

An economical stepping motor control system can be provided by using a gated fixed-reference oscillator in the closed-loop circuitry for the stepping motor, as shown in Fig. 1. The gated fixed-reference oscillator is a sequential latch-back type using a plurality of single shots such as those designated SS1, SS2 and SS3. The fixed-frequency operation of these devices determines the free-running speed of the motor and is used as a reference to determine the degree of lead or lag of each motor drive pulse, which is supplied from a suitable emitter.

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Gated Fixed Reference Oscillator Stepping Motor Speed Control

An economical stepping motor control system can be provided by using a gated fixed-reference oscillator in the closed-loop circuitry for the stepping motor, as shown in Fig. 1. The gated fixed-reference oscillator is a sequential latch-back type using a plurality of single shots such as those designated SS1, SS2 and SS3. The fixed-frequency operation of these devices determines the free- running speed of the motor and is used as a reference to determine the degree of lead or lag of each motor drive pulse, which is supplied from a suitable emitter.

The feedback emitter pulses are supplied from a conventional emitter connected to the motor shaft, and not shown, which supplies an input to the oscillator chain. The single shots turn on in sequence, as can be seen from an inspection of the timing diagram of Fig. 2, and when single shot SS3, the last in the oscillator chain, turns off, a motor drive pulse is generated via an inverter and a single shot designated SSD, which motor pulse serves to control the motor driving circuits.

If the next emitter pulse is late, indicating that the speed is slow, the motor drive pulse generated will have a lead angle value greater than normal indicating that a slower speed condition exists. This drive pulse will be applied before the next emitter pulse occurs. When the emitter pulse does occur, it again gates on the oscillator chain.

If the next emitter pulse is early indi...