Electrical – what will happen if the motor that is designed for delta connected in star connection

deltainduction motorstary-to-delta

I have a motor which is designed for 3 phase, 380V. The power rating of motor is 132kw and motor stator winding is connected in delta connection. If I connect the same motor stator winding in star connection with same 380 V line voltage, what will be the impact on motor line current and power rating of the motor.

Best Answer

When you connect it in a star configuration, the voltage across each of the stator windings will be reduced by \$\sqrt3\$ and correspondingly, the peak mechanical power that could be delivered to a load for a given slip and supply frequency will be lowered significantly.

So, for a comparable slip, the current and voltage will both be reduced by about \$\sqrt3\$ and hence the power delivered to a load is reduced by about 3.