What Is a Dol Starter: Wiring Diagrams Explained

A Direct On-Line (DOL) starter is one of the simplest and most commonly used motor starters. It is a straightforward device that helps protect electrical motors from high currents, damage and overloads. In this article, we will explain what a DOL starter is, how it works and provide a comprehensive look at wiring diagrams for different types of DOL starters.

A DOL starter is one of the most widely used motor starters in the industrial field. It is an electromechanical system used to automatically start and stop an electric motor by using an electric current. When the electric current reaches a certain level of intensity, the starter switches the motor off or on. The starter also controls the speed of the electric motor. While the device may seem simple, wiring diagrams are essential in order to properly connect and configure the starter correctly.

What Does a DOL Starter Do?

A DOL starter is composed of two parts: the main contactor and the overload relay. The contactor is a switch-like device that carries the main current for switching the motor on and off. It is usually made from metal and its contacts open or close according to the demands of the electric current. The overload relay is designed to protect the motor from overloading and short circuits. When the current exceeds the preset values, it will trip the contactor, thus turning off the motor.

Wiring Diagrams for DOL Starters

Wiring diagrams are necessary when installing or configuring a DOL starter in order to ensure it works properly. They provide detailed instructions on where to connect each wire and how to make the connections. The diagrams can vary slightly depending on the type of DOL starter being used.

One of the most common diagrams is the three-phase DOL starter wiring diagram. This diagram shows how to connect the main contactor and overload relay to the power source, control circuit, and motor. It also shows the control circuit's wiring, including the contactors, overload relays and auxiliary contacts. In addition, the diagram illustrates how to wire the neutral and earth cables.

Another type of diagram is the single-phase DOL starter wiring diagram. This diagram shows how to connect the main contactor, overload relay and motor to the power source and the control circuit. It also illustrates how to connect the control circuit’s wiring, including the contactors, overload relays and auxiliary contacts. Additionally, it shows how to wire the neutral and earth cables.

Conclusion

A DOL starter is a simple and efficient way to automatically start and stop an electric motor. Properly wiring the starter requires understanding and following the wiring diagrams for the specific type of starter. By taking the time to read and understand the diagrams, users will be able to install and configure the starter correctly and safely.

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