Working in Under Voltage

Thank you

If the voltage is insufficient to supply the current needed to supply torque to the load (current and torque are roughly proportional) then the motor will stall. Many motors have a fan on them to pass cooling air over the motor casing driven by the motor shaft, and this fan will stop too. If the motor stalls, then the current will be about 5 times the full load current multiplied by the ratio between the actual supply voltage and the design supply voltage. At this point the device isn't a motor; it's a convector heater. If this motor is adequately protected for stall conditions, the overload protection device will operate, reducing the current drawn by the motor to zero.

So it the motor overheats, the overload protection device either isn't doing its job as it has been incorrectly set, or has been bypassed to keep the motor on regardless, or simply hasn't been fitted.

HP or kW = Root3 VL IL Cos phi. If the HP demanded by the driven load is constant, then to satisfy the above equation, if the voltage falls there would be a corresponding increase in Current.