Brian Matthew Haskell

US Patent:

57125481, Jan 27, 1998

Filed:

Jan 16, 1997

Appl. No.:

8/784765

Inventors:

Bill Tice - Vista CA
Brian Matthew Haskell - San Marcos CA

Assignee:

ETI Systems, Inc. - Carlsbad CA

International Classification:

H02P 312
H02P 122

US Classification:

318293

Abstract:

A motor actuator for preventing a motor from drawing excess current for longer than a predetermined time delay period including dynamic brakes for simultaneously braking motor rotation when motor operation is terminated for any reason. Source voltage supplies an input to a voltage regulator which in turn supplies a regulated voltage to the motor. The actuator includes a comparator circuit that has one input connected to motor supplied regulated voltage and a second input connected to the source voltage with the voltage level from source voltage adjusted to a level that is equal to the regulated motor voltage level under normal motor operational loads. When the motor draws excessive current the voltages on the comparator inputs become unequal which causes the comparator to have an output voltage. An RC circuit from the comparator output to ground potential delays the comparator output voltage for a predetermined time. When the predetermined time is exceeded voltage appears on the comparator output causing a switching element, shown as a relay, to switch the motor supply voltage off and Mos Fet conducts providing rotational braking when power is removed from the motor.