| 摘要 |
<p>PURPOSE:To switch a constant torque operation to a constant output operation automatically through a simple constitution by switching an armature voltage control to a field current control according to an armature current. CONSTITUTION:An armature chopper control circuit 11 controls a chopper 2 according to a deviation between an armature current command signal VI and an armature current signal VC. With a bias signal DELTAVCO applied thereon in this case, a field current command unit 14 produces a positive output, and a maximum voltage VFI1 is supplied to a field chopper control circuit 9. When an armature voltage comes to equal the voltage of a DC power 3, the armature current signal VC decreases, the field chopper control circuit 9 is supplied with a voltage decreasing according to an output voltage of the field current command unit 14, thus shifting to a field-weakening control.</p> |
