| 摘要 |
PURPOSE:To eliminate the possibility of an electric shock by setting a regenerative power consuming circuit in a conductive state when a no-fuse breaker is interrupted, thereby discharging the stored charge of a smoothing condenser. CONSTITUTION:3-phase alternating currents are converted by a converter 3 into a direct current, smoothed by a smoothing condenser 4, converted by an inverter 6 into a variable frequency alternating current, and supplied to an AC motor 8. In case of the maintenance of an elevator, when no-fuse breakers 1, 14 are opened, the power supply to a relay 17 is interrupted, the relay 17 is dropped out, and its normal-closure contact 17a is closed. Accordingly, a transistor 5b is conducted, and the charge stored in the condenser 4 is rapidly consumed by the resistor 5. |
