A motor starter is a device for motor control applications and is used to start and stop a motor. A starter is an electromechanical switch similar to a relay, the main difference being that a starter contains a contactor and overload protection to prevent electrical overloading of the motor.
Types of Motor Starter
- DOL Starters - Direct On Line (DOL) or across the line starters are the most common general purpose starter. A magnetic contactor connects the full voltage of the power supply directly to the motor with an overload relay for protection against short circuit, energizing the coil pulls the contactors together to close the circuit and start the device. They are used for motors that are only required to run in one direction at a single speed.
- Reversing DOL Starters - these motor starters can run a motor either forwards or backwards. These three-button starters are particularly useful for conveyor based machinery, where reversing the direction is sometimes necessary.
- Star Delta Starter - a reduced voltage motor starter designed to control a three-phase induction motor, the windings in this starter are switched between star and delta connections to start the motor. A star delta circuit will have a contactor configuration within the relay of. triple pole (star) and double throw (delta).
- Soft Starter - typically used to control AC electric motors a soft starter works by helping reduce the torque and load in the power up and electrical current surges that are typical with motors during their start-up phase. It uses solid-state switches to control the voltage as well as the starting current supplied.