| 摘要 |
An N-phase open-phase type excessive voltage protection circuit breaker is provided to protect electronic components by preventing an excessive voltage from being generated due to an erroneous wiring inside a main circuit breaker. A current limiting portion(U1) includes a first resistor and a first capacitor, which low a current of a 3-phase 4-line circuit breaker to 25 to 30mA, and a second resistor for charging/discharging the first capacitor. A bridge diode(D1) rectifies the AC source voltage of the 3-phase 4-line circuit breaker. A photo-coupler(U2) is connected to one end of the bridge diode, and receives a current of the current limiting portion, when an N-phase open phase is generated. Then a photo-transistor inside the photo-coupler outputs an electrical signal of a light emitting diode. A third resistor is connected to one end of the bridge diode. A DIAC(DA1) has a break-over voltage range of 35 to 45V. A base of a thyristor(Q1) is connected to the photo-coupler and the DIAC. A trip coil(L1) receives a signal from the thyristor.
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