DOL Starter Wiring Diagram For 3 Phase Motor Controlling

Three phase dol starter wiring is most used connection for controlling a three phase motor. In this post you will see the simple dol starter wiring diagram. Which is very simple to understand the complete connection. In the diagram you will see the three pole MCCB circuit breaker ( molded case circuit breaker), a magnetic contactor, a motor over current thermal overload protection relay. and NC (Off switch) and NO (ON switch).

Three Phase DOL Starter Wiring Diagram for 3 Phase Motor

In three phase dol starter wiring, the two types of wiring done. One wiring called main wiring which is used for motor. And one wiring is called controlling wiring.

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.

dol starter wiring diagram

In the above three phase dol starter wiring diagram. All connection i shown with complete guide. The 3 phase incoming supply shown (L1, L2, L3). The three phase supply is connected the MCCB circuit breaker. From where we can switch off the incoming supply to the direct online starter.

From the MCCB the 3 phase supply goes to the contactor main contacts. And from the contactor the supply goes to the thermal overload relay. And from motor over current relay the supply goes to the motor.

The earth wire connect to the motor. These called the main wiring.
And the other wiring called controlling wiring. The NC switch used for motor OFF and NO push button use for the motor ON. The complete wiring shown in dol diagram.

In which the neutral (N) wire goes to thermal overload relay NC contacts (the neutral wire is also connected to the light indicator). And from the motor protection relay NC (auxiliary) the neutral wire goes to the contactor coil A1 terminal.

A line wire comes to the normally close push button from the L3 out from the molded case circuit breaker terminal. From the NC switch a wire goes to the normally open push button switch (for motor ON). And other wire goes to the contactor NO auxiliary contact. This is called the Hold current wire. From 2nd terminal of NO switch (green switch) a wire goes to the other side of NO auxiliary contacts of contactor and to the coil A2 terminal. This wire called touch wire or starting current wire.

The Line wire connected to the relay NO terminal. And from other NO terminal the line wire goes to the light indicator. This indicator will be on when motor trip due to over current flow.

Also click:

MCCB Wiring Diagram For 3 Pole 4 Pole


I hope this three phase dol starter wiring or 3 phase motor wiring with direct online starter diagram help you. Now if you have any question then use can use the below comments section. And if you learn something from the diagram then also share this post….


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