| 摘要 |
PURPOSE:To reduce the number of parts in a current type inverter by specifying a main thyristor of a power inverter for closing an initial charging circuit of a commutation condenser, thereby eliminating the necessity of providing the initial charging circuit through other main thyristor. CONSTITUTION:When a start command is applied to a control circuit 6, contacts S1-S6 of a switch SW1 are closed, and a ring counter RC simultaneously receives a reset input to be reset. Accordingly, auxiliary charging circuits 5-1, 5-2 are connected to a power inverter 3, thereby firing main thyristors W, Y. In this manner, commutation condensers Cv, Cw, Cx, Cy are charged, thereby becoming the state that the thyristors W to U and the main thyristors Y to X are converted. When the pulse time width which is outputted from one shoot multivibrator SS is elapsed, the reset input of the ring counter RC is eliminated, the inverter 3 is completely started, the contacts S1-S6 of the switch SW1 are opened, to isolate the circuits 5-1, 5-2 from the inverter 3. |
