Types of Motors

Electric motors are used mostly in the automobile and manufacturing industries. There are different types of electric motors present in the market. We can choose electric motors based on the operation, applications and voltage. Every electric motor has two parts, named armature winding and field winding.

The main function of a field winding is to produce a fixed magnetic field, whereas an armature winding looks like a conductor arranged within a magnetic field. Due to the presence of a magnetic field, the armature winding uses energy to generate a sufficient amount of torque so that the motor shaft can move.

There are two types of electric motors, AC motor and DC motor. In addition, there are some special motors, such as brushless motor, hysteresis motor, stepper motor, reluctance motor, universal motor, etc.

DC motors

A DC motor works with the help of a direct current. It converts electrical energy into mechanical energy. When a current-carrying conductor is placed in a magnetic field, it experiences a torque and tends to move. In other words, a mechanical force is produced. A DC motor works on this principle. Fleming’s left-hand rule determines the direction of a DC motor. According to Fleming’s left-hand rule, the index finger represents the direction of the magnetic field, the thumb represents the direction in which a DC motor shaft experiences the force, and the middle finger indicates the direction of the current.

There are different types of DC motors. Let us study about them.

1. DC shunt motor – A DC shunt motor works on the direct correct. The windings of this motor resemble armature windings. In this, the field winding is linked in parallel, creating a shunt.

2. Separately excited motor – A stator and rotor connection is done using different power supplies in a separately excited motor. With the help of different power supply sources, the motor is controlled from the shunt, and the armature winding is strengthened to generate flux.

3. DC series motor – The operation of a DC series motor depends on electromagnetic law. According to the electromagnetic law, whenever a magnetic field is found around the conductor, it interacts with an external field to cause rotation in the conductor. The rotor windings in a DC series motor are connected in series. They are mostly used as starter motors in elevators in cars.

4. PMDC motor – Permanent magnet DC motor can be inbuilt with the help of a permanent magnet, which produces a necessary magnetic field for the electric motor operation.

5. DC compound motor – It is a hybrid of DC series and shunt motor. In a DC compound motor, the rotor and stator can be connected through shunt and series windings. The series of windings inside a DC compound motor is designed with the help of copper wire winding to create a small residence path. On the other hand, a shunt winding inside a DC motor is made with the help of multiple copper wire windings to get full input voltage.

AC motors

In an AC motor, alternating current is converted into mechanical energy. The working principle of an AC motor is the same as that of a DC motor. It also works on the principle of Fleming’s left-hand rule. Different types of AC motors are:

1. Induction motor – It is also known as an asynchronous motor. In this, the concept of Faraday’s law of electromagnetic induction takes place. A rotating magnetic field of the stator winding produces an electric current in the rotor, producing torque. When the current flows in the stator, it also generates a magnetic flux. Now there are two fluxes in an induction motor. These fluxes assist each other in the working of an induction motor.

2. Synchronous motor – In a synchronous motor, a steady-state is achieved when the frequency of applied current matches the rotation of the shaft. In addition, the total number of turns is equal to the integral multiple of the applied current frequency. The working of a synchronous motor does not depend on the induction current. In contrast, multiphase AC electromagnets produce a magnetic field for the movement of the stator.

3. Single-phase motor – A single-phase AC motor converts electrical energy into mechanical energy to do specific tasks. It requires only one power phase for its operation. These are commonly used in low power applications in industries and for domestic purposes.

4. Three-phase motors – It works with the help of electromagnetic interactions. In a three-phase motor, additional starting devices are not required. These are also known as self-starting induction motors as they only consist of a router under the starter.