The invention relates to a
voltage signal conditioning circuit of an automatic reclosing lock breaker in the time of electric leakage. A
phase line of power supply phase
voltage or line
voltage goes through the
anode of a
diode D1 and the
cathode of the
phase line is connected with one end of a
resistor R1. The voltage
signal conditioning circuit further comprises a phase voltage and line voltage selecting circuit, a voltage feedback circuit, a
diode D2, a direct-current power supply VCC, an analog-
digital converter AD1, a
resistor R4 and a
filter capacitor C1. A null line of the phase voltage and line voltage selecting circuit or the other
phase line of the line voltage is connected with the input end of the phase voltage and line voltage selecting circuit. One end of the voltage feedback circuit is connected with the R1 and the other end of the voltage feedback circuit is connected with the phase voltage and line voltage selecting circuit. The
diode D2 is connected with the voltage feedback circuit. The direct-current power supply VCC is connected with a photoelectric coupler U1a. The analog-
digital converter AD1 is connected with a photoelectric coupler U1b. One end of the
resistor R4 is connected with five pins of the photoelectric coupler U1b and the other end of the resistor R4 is connected to the ground. One end of the
filter capacitor C1 is connected with the analog-
digital converter AD1 and the other end of the
filter capacitor C1 is connected to the ground. The voltage
signal conditioning circuit of the automatic reclosing lock breaker in the time of electric leakage can solve the problem of temperature excursion, improve
linearity and achieve common use of a three-phase three-wire
system and a three-phase four-wire
system.