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Phase Control of Stepping Motor

IP.com Disclosure Number: IPCOM000091126D
Original Publication Date: 1969-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Hollaway, JT: AUTHOR

Abstract

The circuit advances or retards the application of the electrical field, taking into account phase lead and lag between magnetic and electric fields of a stepping motor during acceleration.

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Phase Control of Stepping Motor

The circuit advances or retards the application of the electrical field, taking into account phase lead and lag between magnetic and electric fields of a stepping motor during acceleration.

Stepping motor 1, drawing 1, is operable in an incremental mode or in a continuous mode to drive stepping ratchet to engage with tape 3 for sensing of signals by head 4. Motor 1 has an electrical field applied to its windings 5...8 by appropriate triggering of transistors 10...13. During incremental operation, transistors 10...13 are selectively energized with an initial heavy start-up current controlled by start control circuit 15 as described in "Stepping Motor Control Circuit" in the IBM Technical Disclosure Bulletin, page 1912, Volume 10. In this circuit, motor 1 drives emitter 16 that steps counter 17, the output of which is provided to phase control circuit 18, having various logic including a single shot for determining the advancement or retardation of the application of the electrical fields determined by energizing transistors 10...13.

In an incremental mode, the terminal voltage of motor 1 is advanced in a regular sequence by one phase setting up a phase lag of 90 degrees between magnetic and electrical fields, thus causing the motor rotor to move to the next detent position. See the phase relationships in drawing 2.

In a continuous slewing mode, the phase lag between magnetic and electric fields is maintained by using a positional feedback signal to advance the electrical field. Thus, the phase lead of the electrical field is maint...