A Brief Overview of The Types of Motor Starters

Motor starters are a vital component of electrical systems all over the world today. Their primary function involves protecting your electrical equipment — your motors, more specifically — from any potential damage that might be caused by electrical fluctuations, including too much and too little power.

Advances in electrical engineering have led to the increasing availability of a wide range of motor starters to suit many use cases and needs. Motor starters also offer distinct functionality from relays: where motor starters are specifically designed to offer your motors overload protection while being turned on, relays do not offer this protection.

What Is A Motor Starter?

A motor starter makes use of a specifically engineered electromechanical switch that can be used to turn a motor on and off. Motor starts are designed to protect motors from electrical overloads and even faults during this process.

Motor starters are made up of two components: a contractor which closes the circuit to the motor and a specially designed electromechanical relay that tracks the amount of power the motor needs and can be supplied. If the voltage is higher than this threshold, the motor starter regulates power flow to the motor to protect it.

Types Of Motor Starters

Motor starters come in a wide range of capacities and ratings to meet various needs and use cases. Functionally, however, they are all designed to protect motors from receiving more current than it should.

1. Stator Resistance Motor Starters

Stator resistance motor starters function by applying a small charge of electricity to the motor through a series of external resistance in phases. These resistances are turned up to their maximum at the moment the motor is turned on, which results in a reduced amount of electricity being applied to the motor to start it up.

Once the motor starts working, the resistance at each phase is slowly reduced and the total amount of electricity required by the motor is supplied to it.

2. Auto Transformer Motor Starters

Auto transformer motor starters make use of a device known as a three-phase auto transformer, which is connected to the motor to reduce the electricity it receives when starting up.

This type of motor starter makes use of a component known as a changeover switch to control the power supplied to the motor. It, thus, has two conditions: reduced voltage and full voltage. In this motor starter, the control of power does not take place gradually. These motor starters are widely used with star and delta three phase motors.

3. Star Delta Motor Starters

Star delta motor starters are likely the most widely used type of motor starters — they are both cheap and compatible with many kinds of induction motors. In star delta motor starters, the motor is connected in a star configuration while it runs on rated speeds.

Star delta motor starters are extremely cost-effective, economical, and maintenance-free in relation to other types of motor starters. However, it’s worth noting that they work only with delta-connected motors and are restricted to only one factor of reduction at the starting speed.

4. Soft Motor Starters

Soft motor starters make use of semiconductor power switches to control the current supplied to motors when they are turned on. They also make use of thyristors to control the supply of electricity in a stepless manner, which allows the motor starter to function seamlessly.

For a user, this means there are no abrupt jerks or interruptions when the motor is started. Once the motor is functioning at full capacity, the thyristors allow the full flow of electricity to reach the motor. Soft motor starters are also equipped with other protections, such as low voltage protection, single phasing, and overload protection.

Join Hands with Skilled Professionals

Motor starters are a vital component in running motors today. They are extremely effective in protecting and prolonging the lives of motors, including by controlling their operating speed at start-up and removing abrupt jerking in the motor. If you are looking to invest in motor starters, you should consider collaborating with reputable brands because they provide unmatched quality with guarantees.