Automatic torque taper circuit

Claim 1

In a motor drive system which includes a control circuit that produces a current command signal to a converter that controls the magnitude of the current applied to a motor, the improvement therein comprising: means coupled to the motor for producing a signal (V s ) proportional to motor speed; means for producing a reference signal (V B ); an analog divider circuit having a divisor input connected to receive the speed signal (V s ) and a dividend input connected to receive the reference signal (V B ), the analog divider circuit being operable to produce an output signal proportional to the ratio of these signals (V B /V s ); and an output amplifier connected to receive the reference signal (V B ) and the output of the analog divider circuit (V B /V s ) and being operable to produce a current limit signal to the control circuit which is proportional to the difference between these signals (V B /V s -V B ).