Browse Prior Art Database

Motor Control Having BEMF Dynamic Braking

IP.com Disclosure Number: IPCOM000074939D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Van Winkle, HE: AUTHOR

Abstract

The illustrated motor control circuit automatically dynamically brakes motor 10 whenever power supply 11 fails or is turned off. During normal operation of motor 10, a velocity set point or control signal is supplied over terminals 12 through bipolar amplifier 13, switch 14, and bipolar driver transistors 15. Switch 14 is actuated to the illustrated position by coil 16 being powered by power supply 11.

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Motor Control Having BEMF Dynamic Braking

The illustrated motor control circuit automatically dynamically brakes motor 10 whenever power supply 11 fails or is turned off. During normal operation of motor 10, a velocity set point or control signal is supplied over terminals 12 through bipolar amplifier 13, switch 14, and bipolar driver transistors 15. Switch 14 is actuated to the illustrated position by coil 16 being powered by power supply 11.

Upon turning power supply 11 off, coil 16 releases switch 14 to terminal 17, the dynamic braking position. BEMF (back electromotive force) of motor 10 is supplied over line 18 to the emitter-base portions of transistors 15. Either polarity of BEMF is connected via the respective transistors through switch 14 and resistor 21 to ground reference potential Most of the BEMF power is dissipated in transistor 15.

Current limiting at transistors 15 may be provided. Also, switch 14 may be solid-state such as an FET.

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