OVERCURRENT DETECTOR FOR SMALL-SIZED DC MOTOR

摘要

PURPOSE:To detect an overcurrent in response to a speed by automatically decreasing the detected current value in response to the speed. CONSTITUTION:An armature current integrator 6 integrates the absolute value of an armature current signal of a DC motor from a current detecting resistor 2 and the absolute value of a speed signal from a tachometer generator 3. A comparator 7 outputs an overcurrent signal when the output signal of the integrator 6 increases higher than the set current value Ref. Thus, since the detected current value automatically decreases in response to the speed, it can protect optimally against the overcurrent in response to the speed.