| 摘要 |
PURPOSE:To enable to match the phases at the time of switching from a half voltage to a full voltage without a tachometer generator by detecting the voltage variation of a synchronous motor by a transformer for an instrument, shaping with constant voltage the detected voltage, and supplying it to a phase detecting relay. CONSTITUTION:To start a synchronous motor 1, a half voltage breaker 5 is closed, and the motor 1 is first started by a damper with the half voltage. Thereafter, the breaker 5 is opened, the voltage variation of the motor 1 itself is produced by a transformer 9 for an instrument, shaped at the constant voltage by a constant-voltage unit 11, and supplied to a phase detecting relay 8. The relay 8 closed a full voltage breaker 7 when the phase of the motor 1 is coincident to the phase of a full voltage power source 6, and the full voltage is applied to the motor 1. In this manner, the phase matching is carried out without a tachometer generator. |
