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Stepping Motor Damping Control

IP.com Disclosure Number: IPCOM000085704D
Original Publication Date: 1976-May-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Lopour, WA: AUTHOR [+2]

Abstract

Stepping motor 10 has a rotor 11 and stator poles 12-15. Each pole has bifilar windings labelled A,C on poles 12, 14 and B,D on poles 13, 15. Rotor 12 is moved in a conventional manner by applying sequential pulses to windings A-D from driver circuits controlled by digital logic or by programming.

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Stepping Motor Damping Control

Stepping motor 10 has a rotor 11 and stator poles 12-15. Each pole has bifilar windings labelled A,C on poles 12, 14 and B,D on poles 13, 15. Rotor 12 is moved in a conventional manner by applying sequential pulses to windings A-D from driver circuits controlled by digital logic or by programming.

When rotor 11 is stopped at a particular pole, it oscillates about a detent position, as illustrated by arrow 16. Such oscillations may be damped more quickly by controlling the windings located at right angles to the detent position. If the north pole N of rotor 11 is stopped at stator pole 12, for example, windings B,D may be energized. Since these windings cancel each other's flux, no net torque is produced. But a current, proportional to the induced voltage, may now flow in windings B,D, so that the kinetic energy of the rotor and its load is dissipated in the windings.

Unlike "reverse step" damping, the position of rotor 11 with respect to pole 12 at the moment of energization is not critical; damping to the proper position will always occur. Likewise, the duration of the energizing pulse is not critical; it is governed only by the amount of time that damping is desired.

To reduce power dissipation in motor 10, windings B,D could be shorted rather than energized. This technique is also applicable to motors with a different number of poles. The greatest damping is obtained when the energized or shorted poles are at right angles to the...