| 摘要 |
PURPOSE:To prevent commutation failure under instantaneous power clutter, by using the forward power rectifier diode of a Scherbius unit and a thyristor unit to absorb an abnormal voltage which occurs across the secondary side of an induction motor under power failure. CONSTITUTION:Thyristors 12-14 are connected in parallel with one another between the current inflow line of a power rectifier 4 and the respective phases of a secondary AC circuit. Under power clutter such as phase disappearance, the thyristors 12-14 are fired by a detection signal from a power failure detector or the like to form a short circuit between the thyristors 12-14 and the current inflow side diode 4b of the power rectifier 4 to immediately absorb an abnormal output which occurs on the secondary side of a motor. |
