The dol starter comprises of an mccb or circuit breaker contactor and an overload relay for protection. A single phase dol motor starter can be designed using the same components as shown in following diagram.

Direct Online Dol Starter Wiring Diagram
Dol starter wiring diagram. Dol starter power circuit diagram. In the above dol starter diagram. The wiring diagram for a dol stater is shown below. We connect the circuit breaker contactor and overload relay in series between electrical supply and motor as shown in below diagram. The coil of the contactor is 380 vac. A direct online starter consits of two buttons a green button for starting and a red for stopping purpose of the motor.
In the above three phase dol starter wiring diagram. And one wiring is called controlling wiring. To wire a 3 phase motor the first thing to wire is a circuit breaker which is disconnect and connecting point then we will get the supply from circuit breaker and connect supply to contactor or starter and then to overload relay. And the normally open and normally close push button shown. Dol starter wiring diagram. The ryb is the three phase 380 volts supply.
Single phase dol starter wiring diagram. Dol starter wiring diagram for three phase motor. All controlling of starter are controlled by this circuit. In the below dol starter wiring diagram i shown a molded case circuit breaker a magnetic contactor normally open push button normally close push button switch thermal overload relay motor trip indicator and 3 phase motor. We have to use all 3 poles of the overload relay otherwise the imbalance due to the current flow in only 2 of them will cause unnecessary tripping. The contactor connection with thermal overload relay and the motor connection with overload relay is shown.
Dol starter control circuit diagram consist components like main power contactor start button stop push button and overload relay is connected in series this circuit is called control circuit of dol motor starte r.