Automatic Star Delta Starter Control Circuit

The connection of a three phase induction motor with a star delta starter is shown in the figure below.

Automatic star delta starter control circuit. The power circuit diagram and control circuit diagram of an automatic star delta starter are explained below. Working of automatic star delta starter control circuit press on push button the star contactor coil gets supply through phase r off push button on push button t nc star contactor coil d1 nc of delta coil phase y. Here you will learn the connection of star delta starter with three phase motor. The star contactor becomes energized and t he timer coil gets supply at the same time.

Working of semi automatic star delta starter control circuit press on push button the star contactor coil gets supply through phase r off push button on push button star contactor coil d1 nc of delta phase y. When star contactor coil km1 energized star main and auxiliary contactor change its position from no to nc. Star delta starter control circuit diagram star delta control circuit star delta motor con. The star contactor becomes energized.

Here the circuit diagram of star delta starter explained in detail. Before going to the power and control circuit of star delta starter let us see the basic principle. Lets understand the star delta starter diagram. Power and control circuit.

Control circuit of star delta starter open transition scheme control circuit of star delta starter open transition the on push button starts the circuit by initially energizing star contactor coil km1 of star circuit and timer coil kt circuit. The basic principle of the star delta starter is that during starting the motor shall have star connected winding and after sometime when the motor have gained adequate speed the winding shall be converted to delta winding. The additional components are a 3 pole contactor and few resistors. A closed circuit transition type automatic star delta starter can be designed by slightly modifying the open circuit transition starting circuit.

Operation working of automatic star delta starter from l1 the phase current flows to thermal overload contact through fuse then off push button on push button interlocking contact 2 and then c3. When the switch s is in the start position the stator windings are connected in the star as shown below. A star delta is used for a cage motor designed to run normally on the delta connected stator winding.