Electric motors are used in a wide variety of applications and, as we all know, are essential in every industry area. Electric motors come in a wide range of designs and types.
In this post, we'll go through the different electric motor types and their useful applications in the modern world. So, let's start with what is electric motor.
What is an Electric Motor?
An electric motor is a device that uses electricity to transform mechanical energy into electrical energy. Electric motors generate torque by interacting with a wire winding and a magnetic field, which creates force along the shaft of the motor.
Although an electric generator and an electric motor are technically similar. An electric generator uses a reversed power flow to transform mechanical energy into electrical energy.
Electric motors can be powered by direct current (DC) sources, such as from batteries, or rectifiers. When necessary, alternating current (AC) sources like a power grid, inverters, or electrical generators can be used.
Electric motors can be categorized based on factors including the type of power source, construction, application, and type of motion output. Depending on their power source, they can be AC or DC, brushed or brushless, single-phase, two-phase, or three-phase, axial or radial flux, and air- or liquid-cooled.
The different types of electric motors and their applications are explained below.
👉 Download This PDF: AASHTO Maintenance Manual for Roadways and Bridges
Types of Electric Motors
There are three main types of electric motors: DC motors, AC motors. and special-purpose motors.
#1 DC Motor
 |
| DC Motor |
A motor that converts direct current (DC) energy into mechanical energy is known as a DC motor. Around the 1830s or 1840s, the first DC motor was created. As these motors were battery-powered and batteries were still very expensive, they were not commercially available.
Armature and Stator are the two main components of a DC motor. The armature and Stator both have rotating and stationary components. There are various types of DC motors based on their structure and electrical connections.
1. Separately Excited DC Motor
 |
| Separately Excited DC Motor |
In this motor, a separate DC source is used to excite the DC windings. The motor's armature windings are powered by a separate DC source, and as a result, the flux is generated.
2. Permanent Magnet DC Motor (PMDC)
.JPG) |
| Permanent Magnet DC Motor |
A permanent magnet DC motor (PMDC) is a type of motor that generates field flux using a permanent magnet. The PMDC motor has excellent speed regulation and more starting torque. However, the torque is limited. They are frequently used in applications like air conditioners, wipers, and car starters.
3. Self-Excited DC Motor
Self-excited DC motors are those in which the field winding is connected to the armature winding either in series or parallel. The self-excited DC motor are further categorized, which are as follows:
a) DC Shunt Motor
 |
| DC Shunt Motor |
b) DC Series Motor
 |
| DC Series Motor |
In a DC series motor, the rotor windings are linked in series. This motor's basic operating principle is based on the electromagnetic law. It states that rotational motion occurs whenever a magnetic field is formed around a conductor and interacts with an external field.
These motors are primarily used in the starter motors for cars and lifts.
c) Compound DC Motor
The field winding of the compound motor is connected in both parallel and series. Depending on the type of compounding, there are two different types of excitation for a compound DC motor.
- Cumulative compound DC motor:- Here, the main field flux created by the series winding is assisted by the shunt field flux produced by the shunt winding.
- Differential Compound DC Motor:- In this case, the motor is acting as the shunt field flux reducing the impact of the main series winding.
👉 Download This PDF: INDUSTRIAL MOTOR CONTROL
#2 AC Motor
 |
| AC Motor |
The AC motor is usually operated on alternating current to rotate. This motor uses electromagnetic induction to transform alternating current into mechanical power. The stator and rotor are the two most crucial components of the AC motor.
The stator is the stationary component and the rotor is the rotating component. AC motors are typically either single-phase or three-phase. The three-phase AC motors are primarily used to produce large amounts of power.
The single-phase AC motor performs a variety of tasks. These motors are employed in low-power systems. The majority of household appliances, including fans, washers, dryers, refrigerators, and mixers, use single-phase AC motors.
AC motors are broadly classified into three types:
1. Synchronous Motor
 |
| Synchronous Motor |
The synchronous motor's operation is primarily dependent on a three-phase power supply. A synchronous motor converts alternating current into mechanical power. This motor stator generates a field current that rotates at a steady speed when AC frequency is applied.
The stator current moves at a similar speed to that of the rotor. There is no air gap in the speed of the stator current and rotor. Thus, it offers greater rotational accuracy. These motors can be used in automation, robotics, and other fields because of their high rotational accuracy.
There are two categories of synchronous motors:
a) Reluctance Motor
 |
| Reluctance Motor |
Reluctance motors have an induction motor-like construction and operate similarly to single-phase synchronous motors. Typical applications for these motors include signal generators, recorders, etc.
b) Hysteresis Motor
 |
| Hysteresis Motor |
The hysteresis motor is a type of synchronous motor as well as a rotating field type of motor. The hysteresis motor lacks a DC excitation system and has a constant air gap. This motor's rotor generates eddy current and hysteresis to carry out the necessary task.
2. Induction Motor
Induction motors are electrical devices that operate at an asynchronous speed. This type of electric motor is also known as an asynchronous motor. Induction motors primarily use electromagnetic induction to convert electrical energy into mechanical energy.
Based on rotor design, induction motors can be divided into two categories: phase wound induction motors and squirrel cage induction motors. The induction motor is divided into single-phase and three-phase induction motors according to the supply phases.
a) Squirrel Cage Rotor
 |
| Squirrel Cage Rotor |
The rotor of this motor is shaped like a squirrel cage. The inner part of this motor resembles a cage and is connected to the output shaft.
b) Phase Wound Rotor
 |
| Phase Wound Rotor |
This motor is a type of three-phase induction motor that is intended to draw very little current while delivering high torque for loads with high inertia.
c) Single-phase Induction Motor
 |
| Single-phase Induction Motor |
A single-phase induction motor uses electromagnetic induction to transform single-phase AC electric energy into mechanical power.
d) Three-phase Induction Motor
 |
| Three-phase Induction Motor |
A three-phase induction motor transforms three-phase alternating current (AC) electric energy into mechanical power.
3. Linear Motor
 |
| Linear Motor |
Electric motors with their rotor and stator unrolled are referred to as linear motors. This motor generates a linear force along its length, as opposed to rotational torque. Most often, linear motors are used in actuators and on sliding doors.
Special Types of Electric Motors
There are many types of DC or AC motors with a wide range of specifications on the market, including stepper motors, servo motors, brushed DC motors, brushless DC motors, and others.
#1 Stepper Motor
 |
| Stepper Motor |
DC motors that divide a complete rotation into a number of equal steps are known as stepper motors. They have plenty of coils, and each one is arranged into phases of coils. Upon energizing each phase of this motor, it rotates one step at a time.
Due to the fact that each pulse enables the motor to rotate at a precise angle of 1.8°. The positioning and speed control offered by this motor are extremely precise. Stepper motors are used in plotters, circuit fabrication, process control tools, standard movement generators, and other applications.
#2 Brushless DC Motor
 |
| Brushless DC Motor |
Brushless DC motors were initially developed to achieve superior performance in a smaller space than brushed DC motors. When compared to AC motor designs, these motors are smaller. A controller has been placed in this motor to facilitate the process in the absence of a commutator and a slip ring.
#3 Servo Motor
 |
| Servo Motor |
An electric motor that rotates machine parts precisely and efficiently is known as a servo motor. Both AC and DC versions of the servo motors are available. It is a type of rotary or linear actuator that permits precise control of acceleration, velocity, and position in either a linear or angular direction.
Servo motors are used in a wide range of applications, including toy cars, RC helicopters and planes, robotics, and so on.
#4 Universal Motor
 |
| Universal Motor |
This particular type of motor requires a single AC supply; otherwise, it requires a DC supply. This type of motor generates high starting torque since the field and armature windings are connected in series. These motors are primarily made for high-speed use above 3500 rpm. They use a DC supply with a similar voltage and a low-speed AC supply.
Final Thought
I sincerely hope that this article assisted you in understanding the specifics of the "different types of electric motors." It would be helpful if you could let me know if there was anything I missed or if you have any doubts about anything I wrote.
Please share this article with your friends if you find it interesting.
Internal Links:
Reference [External Links]: