Motor protector circuit diagram 7

Published:2011/5/21 1:26:00 Author:Lucas | Keyword: Motor protector | From:SeekIC

When the three-phase power supply is normal, the public contact 0 of detection capacitor C1 ≈ C3 has no current flowing, the two ends of C4 have no voltage, and the crystal tube VT is off, the relay K does not pull in, its normally closed contact is connected, the LED VL does not emit light, the motor M operates normally (in fact, the three-phase voltage unbalance, or the capacity of C1 ~ C3 differ will cause O point having a small current to flow, but the K doesn't move.) KR is the thermal relay, S1 is the Close button, S2 is the start button, R is the current limiting resistor. Potentiometer RP, capacitor C5 or intergranular tube VT form delay circuit to prevent serious harmonic interference or instantaneous voltage fluctuations and protector's malfunction. RP's positive adjustment value can change the conduction delay time of VT (generally 0.5 ~ 1s).



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