How use 3 phase failure relay for 1 phase motor by a 40A magnetic contactor for protection from abnormal voltage?

Upper side of relay has 3 screws(1,2,3)

Down side has 6 screws (7,8,9 & it's down (13,14,15))

Features & details

Supply Voltage System : 100-120/220-240/380-440 V AC ± 20% 50/ 60 Hz Auxillary : 100-120/220-240/380-440 V AC ± 20% Output Contacts : 1 CO Trip Setting(Volts) Phase Sequence : Yes Phase Unbalance : 40 V± 6 V (fixed) Trip Time Delay On Phase Failure/ Unbalance : 3.5 sec.± 1.5 sec. For Level Sensing : NA Resetting Mode : Auto

Mounting (L x W) : 68 centre to centre/ 35 mm rail Mounting

Phase Failure, Unbalance, Phase Sequence, Auto Reset, Fixed Unbalance Setting 1 CO output Relay

2 Answers

  • ?
    Lv 7
    7 months ago

    What is this obsession with overvoltage protection?

  • 7 months ago

    Since this relay was designed on 3 phase power source to control a 3 phase motor, and now you want to replace the motor with a single phase. You need to add a 3 phase to one phase transformer between the relay 3 phase power out  and single phase motor. No need to modify the relay circuit and be sure the transform VA rate at least 200% higher than the motor VA rate to allow motor starting current surge.

    Transformer 3 phase input voltage 380V phase to phase, secondary output voltage 230V ( matching to the motor voltage ). 

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