| 摘要 |
PURPOSE:To prevent the production of a surge voltage by discharging the charge stored in a condenser of a snubber of a thyristor for a main thyristor bridge through the thyristor of an auxiliary thyristor bridge without passage of the coil of a motor. CONSTITUTION:When commutating from the first phase to the second phase, an ON signal is applied to the second phase thyristor of a main thyristor bridge, and the thyristors 52, 53 of an auxiliary thyristor bridge corresponding to the phase except the first phase are simultaneously conducted. The condensers 32C, 33C of the snubber of the thyristor of the main thyristor bridge are shortcircuited through the thyristors 52, 53, and the charge stored in the condensers 32C, 33C can be accordingly rapidly discharged. |
