Capacitor motor phase failure protection circuit

(1) The capacitor Ci-C3 of the motor is connected to the artificial neutral point "E" during normal operation. When the motor is running normally and the three-phase power supply is balanced,
the potential of point "E" is zero, the transformer T2 has no output, the transistor VT is cut off, the relay KA does not pull in, its normally closed contact remains closed, and the motor
runs normally.
    (z) Phase failure protection function When the three-phase power supply has a phase failure or the three phases are unbalanced, the potential of point "E" is higher than zero potential, and the voltage
is coupled , rectified by VD1, filtered by G, and then passed through the voltage regulator v! ;, the resistor Ri and the capacitor G are added to the base of the transistor VT with a delay to make it conductive. The relay
KA is powered and closed, and its normally closed contact is disconnected, causing the KM to lose power and release, and the motor M to stop rotating.