Overvoltage protection circuit diagram

Posted on Mar 28, 2007

As shown in FIG circuit protection circuit is the use of optocouplers or not the on-off control. Voltage is normal, almost no output optocouplers, VT pipe is reverse biased and

Overvoltage protection circuit diagram
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off. For some reason when the circuit voltage rises (zero line break or wrongly connected to the zero line phase lines, etc.), along with increased secondary voltage sampling circuit, the optocoupler operating conditions are met. Optocoupler output current increases, the bias voltage is increased and the tube VT saturated conduction, the actuator relay pull, turn off the power to protect electrical purposes. If the fault is eliminated, along with normal voltage, the circuit out of service immediately, recovery circuitry.Component selection: Used optocouplers 4N25 or similar goods. Triode tube 3BG12 rate with *** or 3BG13 can. Relay contacts use 5A or more. Coil voltage can be customized (5V to more than tens of volts can be). Do continued flow tube with a light emitting diode LED, doubles as an indicator. We need to change hands is the power transformer primary 380V calculated according to the maximum (here by the primary 380V RMS calculation), which ensures that once the phase voltage equal to line voltage, the device can work normally they would not damage the secondary voltage according to the relay coil determining the operating voltage, the rectifier circuit can refer to the specific requirements of the technical requirements.

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