| 摘要 |
PURPOSE:To rapidly suppress an excessive current of the DC motor and to improve the acceleration response of the motor by comparing a value obtained by multiplying field current detection value by speed detection value with applied voltage value and suppressing the applied voltage by a signal when the applied voltage is higher than the value obtained. CONSTITUTION:The field current value If and the speed detection value Vn are introduced into a multiplication amplifier curcuit 17, and the output Vz from the circuit 17 and a signal Vb for determining an armature applying voltage are inputted to a comparison amplifier circuit 18. The circuit 18 compares in amplitude the signal Vb with the signal Vz to produce a zero signal when the signal Vz is higher than the signal Vb and to produce a deviation Vb-Vz when the signal Vb is higher than the signal Vz. The output signal from the circuit 18 is inputted to an addition and subtraction amplifier circuit 16 for producing the signal Vb. When the applied voltage becomes excessive in this manner, it rapidly suppresses the excessive voltage to eliminate the excessive current there brought. |
