| 摘要 |
PURPOSE:To suppress the rise of the short-circuit currents of a load circuit and enable selective breaking by a fuse while keeping the drop of output voltage constant without depending upon output frequency by connecting a current- limiter circuit on the DC side of an inverter circuit, and to relax the temperature rise of a current-limiter reactor by reducing the effect of higher harmonics. CONSTITUTION:A current-limiter circuit 5 is composed of bridge-connected diodes D1-D4 and a current-limiter reactor L1 connected among the positive and negative poles of the diodes. An inverter 6 is supplied with DC rectified by a converter 2 through the current-limiter circuit 5. When a short-circuit failure, etc., are generated in a motor 8 and overcurrents are made to flow through the inverter 6, di/dt is suppressed by the reactor L1 for the current- limiter circuit 5, and fuses 7 are blown out during the suppression and the failure motor 8 is selectively cutoff. Lagging currents by the reactor L1 when load currents are interrupted flow back in the current-limiter circuit 5. |
