| 摘要 |
PURPOSE:To start a motor smoothly without flowing an excessive exciting current in a transformer by demagnetizing magnetic fluxes of a transformer core when the motor is stopped and setting the magnetic fluxes of the transformer core at a specified magnitude. CONSTITUTION:The secondary side of a transformer 2 and a motor 1 is directly connected, and a breaker 5 is provided on the primary side of the transformer 2. After the motor 1 is started with a power converter 3, synchronization is made. While the motor 1 is stopped, the signal of a rotary generator 12 is given to a field current command unit 41, the field current which decreases at a rate larger than the speed decreasing rate is flowed, and the magnetic fluxes of the core of the transformer 2 are demagnetized. Before starting, the magnetic fluxes are set so that the specified polarity and magnitude are set with the field-current command unit 41. Since the excessive exciting current is not flowed into the transformer 2, the load of the power converter 3 is reduced, and excellent starting can be accomplished. |
