Types of Electric Motors and Their Applications

In today’s world of automation, electric motors play a vital role in all industries and businesses from automobiles to robotics and home appliances. Electric motors are used to convert electrical energy into mechanical energy to drive different kinds of loads. With technological advancements, different types of electric motors have been developed which are having different characteristics to match the requirements of different applications.

However, the basic construction of all electric motors is the same, having two main components namely, stator and rotor. Where, the stator is a stationary part and the rotor is the moving part of the motor. Since, different applications require electric motor with different characteristics. For example, an electric train requires an electric motor having very high starting torque to pull the train, whereas an elevator requires an electric having a constant speed. Therefore, to meet the demands of different kinds of loads, different types of electric motors are designed. This article is meant for explaining the basics of different types of motors and their applications.

Types of Electric Motors

Based on power supply, electric motors can be classified into the following two types −

• DC Motor (Direct Current Motor)

• AC Motor (Alternating Current Motor)

The dc motors are further classified into the following major types −

• Permanent Magnet DC Motor

• Separately Excited DC Motor

• DC Series Motor

• DC Shunt Motor

• DC Compound Motor

The ac motors are classified into the following major types −

• Single-Phase Induction Motor

• Three-Phase Induction Motor

• Synchronous Motor

There are some special types of electric motors used in practical applications, they are −

• BLDC (Brushless Direct Current) Motor

• Hysteresis Motor

• Reluctance Motor

• Universal Motor

• Repulsion Motor

Let us now discuss practical applications of each of these electric motors.

Applications of Permanent Magnet DC Motor

A permanent magnet dc motor is a one which has permanent magnetic poles in its magnetic field system. This type of dc motor is used in the low power applications. Some practical applications of permanent magnet dc motors are given below −

• Printers, computer memories, CPU fans, etc.

• Automobile wipers, windows, etc.

• Electronic toys.

• Portable vacuum cleaners.

• Camera lenses.

• Portable tools like trimmers, drills, etc.

Applications of Separately Excited DC Motor

A separately excited DC motor is a type of dc motor which has a field winding excited from a separate DC power supply. This type of dc motor is used in the following applications −

• In electric trains and automatic traction systems.

• In actuators.

• In special industrial applications.

• Rolling machines.

• Paper machines, etc.

Applications of DC Series Motor

A dc series motor is one in which the field winding is connected in series with the armature winding. Hence, in dc series motors, the field winding carries equal current to the armature winding and thus produces a high starting torque.

DC series motors are used in applications where high starting torque and variable speed is required. Some common applications of dc series motors in practice are as follows −

• Cranes and hoists

• Lifts

• Electric trains and vehicles

• Vacuum cleaners

• Hair driers

• Air compressors

• Electric hammers, etc.

Applications of DC Shunt Motor

A dc shunt motor has a field winding connected in parallel to the armature winding and receives full supply voltage. Since the voltage across shunt field winding is constant. Hence, DC shunt motors are considered constant speed motors.

The dc shunt motors are widely used in the following practical applications −

• Blowers and fans

• Printers

• Centrifugal pumps

• Lathe machines

• Elevators, etc.

Applications of DC Compound Motor

A dc compound motor is one which has both series field winding and shunt field winding to produce the working magnetic field in the machine. Therefore, this type of dc motor exhibits characteristics of both dc series and shunt motors.

The dc compound motors are used in the following applications −

• Rolling mills

• Electric drives used for conveyor belt

• Elevators

• Compressors

• Electric presses, etc.

Applications of 1-Phase Induction Motor

Single-phase induction motor is a type of alternating current motor that works on single-phase ac supply. These motors are designed to operate light loads used in domestic, commercial, or industrial applications. Some examples of practical applications of single-phase induction motor are listed below −

• Pumps

• Fans and coolers

• Flour mills

• Compressors

• Grinders, and other low power appliances.

Applications of 3-Phase Induction Motor

A three-phase induction motor is an electric motor that requires three-phase supply to operate. It is a most widely used electric motor in industries. These motors are generally used to drive heavy loads and machinery.

A list of some common practical applications of three-phase induction motors is given below −

• Large pumps

• Large compressors, fans, blowers, etc.

• Crushers

• Rolling mills

• Large flour mills

• Textile mills

• Paper mills

• Modern electric trains and vehicles

• Lifts and cranes

• Heavy industrial machinery, etc.

Applications of Synchronous Motor

Synchronous motor is a type of alternating current motor that runs at a constant speed called synchronous speed. The speed of a synchronous motor always remains independent of the load condition on the shaft.

Synchronous motors are widely used in the following applications −

• Drive heavy mechanical loads at constant speeds.

• To drive ball mills, rod mills, in industries.

• In paper mills and cement mills.

• In power plant to improve power factor, etc.

Applications of BLDC Motor

BLDC (Brushless Direct Current) motor is a specially designed dc motor does not have carbon brushes to make connection between moving and stationary components. Since these motors have brushless construction, hence they require less frequent maintenance.

The BLDC motors are commonly used in the following practical applications −

• Modern fans

• Electric vehicles

• Power steering of vehicles

• Lab equipment

• Robotics and automation systems

• Hard disk drives

• Medical surgical tools, etc.

Applications of Hysteresis Motor

Hysteresis motor is a special type of synchronous motor which utilizes the hysteresis phenomenon to operate. It is basically a type of synchronous motor. It provides a silent and constant speed operation.

Some practical applications of hysteresis motors are given below −

• Sound recording and producing devices

• Timing devices

• Compressors and pumps

• Electric clocks

• Tape printers

• Indicating instruments, etc.

Applications of Reluctance Motor

Reluctance motor is a special electric motor which operates on the principle of magnetic reluctance. It consists of a salient pole rotor and a stator similar to the induction motor. In the reluctance motor, the torque is produced in the rotor due to reluctance i.e., the rotor tends to align itself in the position of minimum reluctance.

The following are some common applications of reluctance motors −

• Electric vehicles

• Signaling and control equipment

• Electric clocks

• Recording instruments

• Teleprinters and gramophones

• Drill or lathe machines, etc.

Applications of Universal Motor

A specially design electric motor that can run on both AC and DC power supply is called a universal motor. It is also known as AC series motor as it has a field winding connected in series with the armature winding and commonly operates on AC supply.

Universal motors are used in applications where high starting torque is required. Some common applications of universal motors are given below −

• Table fans

• Hair driers

• Mixer and grinders

• Portable power tools like drill machine, grinders, etc.

• Various electric appliances used in kitchen

• Blowers, etc.

Applications of Repulsion Motor

Repulsion motor is a type of ac motor which operates on the principle of repulsion between two magnetic fields of stator and rotor. It is a type of single-phase ac motor that provides a significantly high starting torque and good operating characteristics.

Reluctance motors are commonly used in the following applications −

• High speed lifts and hoists

• Toys

• Coil winders

• Electric locomotives and vehicles

• Pumps

• Fans

• Machinery used in textile industries

• Printing presses, etc.

Conclusion

In conclusion, electric motors are crucial component of any device or machinery that works automatically. Today, electric motors are used in almost all aspects of life from household to large industries. Also, different loads have different characteristics and hence require different type of electric motor to drive. In this detailed article, I have explained common practical applications of different types of electric motors.