Control system for battery-operated pump
AssigneeMine Safety Appliances Company
InventorGregory A. Bertone
Life of this patent
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Abstract
A motor control system, particularly adapted for use with a battery-operated atmospheric hazard sampling pump, which can vary motor speed over a range of 50:1 with the use of a voltage controlled pulse width modulator. The system includes a back EMF circuit which develops a voltage, proportional to motor speed, which is compared with a speed reference signal to develop an error signal for the pulse width modulator. Automatic shutdown of the motor occurs for controlled periods when a blocked pump condition occurs and motor current rises above a predetermined limit.
Claims5
In a control system for a battery-operated motor, the combination of pulse width modulating means for supplying a pulsed voltage to said motor, means for generating a voltage proportional in magnitude to the speed of said motor, means for comparing said voltage with a reference speed signal to develop an error signal for controlling the width of the output voltage pulses from said pulse width modulator, and means for periodically removing power from said motor for a fixed period when current through the motor exceeds a predetermined limit, the power being periodically removed from the motor for successive fixed periods until the motor current falls below said predetermined limit.
Dependencies are inferred from the claim text.