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Phase loss sensor with control of contactor contacts are designed to protect motors supplied from a three-phase network in the event of a voltage decay in at least one phase or voltage asymmetry between the phases, and damage to the contacts of the switching contactor, which may result in the destruction of the motor. Action
Voltage failure in at least one, any phase or Trip voltage asymmetry [V] between phases above the tripping threshold will cause the motor to turn off. The switch-off will take place with a delay of 4 seconds, which prevents the motor from being disconnected in the event of a momentary voltage drop. Reactivation will occur automatically when voltage increase by 5V above the activation voltage (i.e. by the value of the voltage hysteresis). Failure of any of the contacts of the motor-enabled contactor will permanently disable the motor. Restarting is possible only after complete disconnection of the power supply, removal of the contactor fault and reconnection. With the above anomalies, the engine cannot be started.