| 摘要 |
PURPOSE:To prevent a motor from running away on the basis of a commutation failure at starting point by composing to fire the second thyristor simultaneously upon firing of the first thyristor. CONSTITUTION:The conducting time of a thyristor T1 is varied by altering the counting time of a timer to fire the thyristor T1, a thyristor T2 is then rapidly fired to set the ON time of the thyristor T1 to 0. Thus, if it is controlled to shorten the energizing time of the thyristor T1 at the starting time of a motor M, it can prevent the motor M from running away on the basis of a commutation failure at starting time. |
