| 摘要 |
PROBLEM TO BE SOLVED: To prevent a short circuit from flowing from a capacitor for smoothing when a thyristor for short circuit for protecting it from overvoltage generated in a secondary circuit in the case that accident such as short circuit, grounding, etc., occurs in the primary circuit. SOLUTION: This device stops an inverter 3, detecting the overvoltage generated in the secondary winding of a wound inducer 4 having reached a first overvoltage value with a first overvoltage detection circuit 8, and ignites a thyristor 5 for short circuit and short-circuits the secondary winding of a wound inductor with a switch 5 for short circuit, detecting it having reached the second overvoltage value above the above first overvoltage value. Therefore, the inverter 3 stops before the ignition of the thyristor 5 for short circuit, so a short circuit current does not flow from the capacitor 2 for smoothing. |
