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Browse Prior Art Database

Adjustable Step Motor Rotor Detent

IP.com Disclosure Number: IPCOM000101784D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 1 page(s) / 31K

Publishing Venue

IBM

Related People

Do, PK: AUTHOR [+4]

Abstract

Disclosed is a technique which allows for software control of step motor detent current. The method is based on existing internal system clocks and can be programmed to produce different levels of detent current.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Adjustable Step Motor Rotor Detent

       Disclosed is a technique which allows for software
control of step motor detent current.  The method is based on
existing internal system clocks and can be programmed to produce
different levels of detent current.

      The technique is based on open-loop pulse-width modulation of a
central drive transistor in a circuit such as that in the figure.
The principle is to switch on and off transistor T1 (1) at a constant
duty cycle, thereby setting up an average current proportional to the
duty cycle, in the motor windings.  Since this method is used when
the motor is at rest, Bemf and angular dependencies are minimized;
allowing open loop control based on pre-characterization of duty
cycle with average current level.

      The advantage of this scheme is to minimize control complexity,
eliminate power-consuming components R1 (2) and D1 (3), and allow
programmed selection of a current level.

      This technique has been used effectively and has increased
flexibility and minimized cost.