| 摘要 |
PURPOSE:To conduct damping currents rapidly by changing over and controlling the correlation of an ignition signal from a thyristor for driving the induction motor so that DC damping currents or thinned-out damping currents are flowed by a torque-direction detecting signal and a rotation-direction detecting signal. CONSTITUTION:An operation-state discriminating signal detecting circuit 43 receiving an output signal from a torque-direction signal detecting circuit 41 using a current reference signal from an operational amplifier 23 for controlling speed as an input and an output signal from a rotation-direction signal detecting circuit 42 using a speed signal from a revolution-speed signal circuit 11 as an input outputs an operation-state discriminating signal. The conduction signal of a main circuit thyristor corresponding to the state of operation (power travelling, damping) is outputted from a phase changeover circuit 32 using an output signal from a phase control circuit 31 and the operation-state discriminating signal as inputs. An output from a speed-level signal detecting circuit 51 receiving the speed signal and an output from a thinned-out pattern signal circuit 52 using the operation-state discriminating signal as an input and said conduction signal are inputted to a thinned-out mask circuit 33, and a thinned-out conduction signal of a pattern corresponding to speed is outputted on damping. |
