| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic voltage adjusting device having a long lifetime, which is adaptable to instantaneous voltage variation occurring frequently without causing increase of the cost and inducing increase of the size of the device.SOLUTION: In a tap changer 8 for switching the tap of an adjustment transformer 2, switch main circuits of thyristor switches SS and switch main circuits of mechanical switches MS as load current change-over switches A to C and T1, T2 having liability to switch load current of the adjustment transformer are connected to one another in parallel to construct a composite switch. The thyristor switch SS and the mechanical switch MS constituting the load current change-over switch are controlled so that the thyristor switch SS is set to ON-state, and then the mechanical switch MS is set to ON-state when the load current change-over switch is set to ON-state, and the mechanical switch MS is set to OFF-state and then the thyristor switch SS is set to OFF-state when the load current change-over switch is set to OFF-state.SELECTED DRAWING: Figure 1 |
