Star-Delta Starter - Explained (Power wiring)

Hello friends, my name is Rashid and today I will tell you how to do star delta connection of motor. You must have seen that most of the induction motor whose HP rating is less than 5 kilowatt can be started by direct online method. However, if we start higher HP rating motor in direct online method, then the

starting current and starting torque of motor will be very high due to which the supply voltage will start fluctuating. Generally the starting current of motor is six to seven times more than the full load current. For limit starting current, we use star delta starting method which I will tell you further. Star delta method can step down the

voltage and start the motor at its nominal speed. The terminal of the three-phase induction motor is something like this. It has six terminal. There are three coil in three-phase motor which generate magnetic flux when current flows through it. Due to which the rotor start rotating. Each coil has two ends. As you can see here, each coil is connected

with two terminals. This is motor internal connection. One end of first coil is connected to U1 and another end is connected to U2. Same way second coil of one end is connected to V_sub_1 and other end of same coil is connected to V_sub_2 and the third coil is also connected in the same manner

that is one end with W1 and the other end is connected to W2. We will give three-phase power supply in this three terminal. red phase in U1, yellow phase in V1 and blue phase in W1. If we intend that motor has to run in star configuration, then we have to sort this terminal

together. As you can see in this star circuit, the three terminals of coil L1, L2 and L3 are connected to the power supply and the other end of this coil is short. Same way we do it in the motor to give start configuration. We short these three terminal together with the help of