| 摘要 |
PURPOSE:To stop a motor in a short time by applying reverse phase braking to a regenerative braking to the motor by a brake circuit which is formed of a speed detector, a brake controller, a sequence circuit, a power source switch and a transformer with a tap changer. CONSTITUTION:When a stop switch PB1 is turned OFF, an auxiliary relay RY1 and a solenoid contactor MS1 are turned OFF, a power supply from an inverter 8 to a motor 3 is stopped, a timer T1 is simultaneously operated, the contact of the timer T1 is closed after the set time, a solenoid contactor MS2 is then operated, and a regenerative brake is acted in the motor 3 through a transformer 9 with a tap switch. When a relation of speed detection signal VB<set signal VS2 (having a speed slightly faster than the synchronizing speed) is obtained, the operation of a relay HS is stopped, the timer T1 is turned OFF, the MS2 is turned OFF, and the power regeneration is stopped. Simultaneously, a timer T2 is operated, the contact of a timer T2 is then closed after the set time, a solenoid contactor MS3 is operated, and a reverse phase braking is thus applied to the motor 3. When a relation of VB<set signal VS1(<VS2) is obtained, the operation of a relay LS is stopped, the MS3 becomes OFF and reaches natural stop. |
