Electric Motor Control

Electric Motor Control

Electric motor control refers to a group of devices that ensure the performance of an electric motor in a predefined manner. Electric motor controls (formally known as motor controllers) intend to perform several essential functions such as regulating the torque, selecting the speed of the electric motor, setting the course of rotation, and manually or automatically starting or stopping the operation of electric motors.

You can find a variety of motor controls, each of which uses a different mechanism. A motor control component has two modes, manual and automatic, to select and regulate the operation of an electric motor. This blog will cover the various type and methods of electric motor control to help you understand the right type of control for your electric motor.

Different Types of Electric Motor Control

Controlling an electric motor depends on its intended functions and requirements. However, some common types of controlling an electric motor include;

  • Motor safety control
  • The direction of rotation control
  • Servo or precision control
  • Motor torque control
  • Motor speed control
  • Motor start/stop control

Types of Electric Motor Control Methods

The topic of motor control methods is wide and varied. Various types of motor control methods are used to regulate the performance of motors, some of which are;

  1. Variable Frequency Drive (VFD)

A variable frequency drive is designed to control and regulate the performance of a synchronous motor or AC induction motor. It translates one frequency and voltage to another to regulate the motor speed without losing motor torque. You can use VFD;

  • To minimize the electrical and mechanical stress on a motor
  • To get the quality improvements in your motor’s speed, torque, and acceleration
  • To control and regulate the speed of a manufacturing process accurately


  1. Soft Starters

Soft starters are the additional devices that enable AC electric motors to use a different startup method. This electric motor starter gives a smooth power acceleration to prevent the motor and mechanism from any potential damage. Certain soft starters use solid-state devices to control the current in three different phases, allowing for a more accurate level of control.

You can use soft starters to;

  • Reduce the risk of power surges in pump applications
  • Get the adjustable acceleration time
  • Avoid the initial blast of power associated with the conventional startup.


  1. Motor Starters

Like relays, electric motor starters safely start/stop the motor, reverse its direction, and protect it from overcurrent and low voltage. You can find several electric motor starters, each of which has advantages and disadvantages.

  • Direct Online Starter (DOL)

The simplest form of electric motor starters consists of a magnetic contractor. DOL connects the motor directly to the power supply.

  • Star Delta Starter

Star delta starters are commonly used in industries for large motors. It provides a low surge current and long acceleration time.

  1. DC Motor Control Methods

DC motor controllers manipulate a DC-powered motor's speed, torque, and position. Some common DC motor control methods include;

  • H Bridge circuit (Direction Controller)
  • Pulse Width Modulation (Speed Controller)
  • Variable Resistance (Armature Controller)

Bottom Line

Electric motors require adequate protection devices and controls to meet safety and performance requirements. At Alphateam, we offer a wide variety of electric motor control  systems to satisfy the industrial needs of our clients.