Electric motors are used in almost every mechanical movement done around you. In just about every sector of the industry, from heavy industry to the service sector, electric motors play a critical role. You’ll find them in your house as well as in most electric appliances. If you look around your house, you’ll find that it is filled with electric motors.
Every motor has two essential parts namely the field winding & the armature winding. A field winding is used to create a fixed magnetic field and an armature winding looks like a conductor placed within the magnetic field. Since magnetic fields are produced by armatures, the armature winding uses energy to produce an adequate torque for rotation. The motor can be classified based on its connections, which means how the two coils get wired together.
There are a variety of types of Electric motors available in the market, and these can be selected based on voltage, operation, and applications.
Types of motors
The different applications of electric motors are classified into three categories: AC motors, DC motors, and special purpose motors.
1) DC MOTORS
DC motors are electrical motors that convert direct current (DC) electrical energy into mechanical energy. DC motors can be subcategorized as brushed or brushless. The brushed motors are further classified as shunt wound, series wound, PMDS, and compound wound. This category uses a configuration of wound wire coils as the rotor, also called an armature, acted upon by a permanent magnet. Whereas brushless motors utilize a permanent magnet as their rotor.
DC SHUNT MOTOR: DC shunt motor works on DC and the windings of this electric motor like armature windings and field windings are linked in parallel. This kind of motor is also called a shunt wound DC motor, where the winding type is known as a shunt winding.
SEPARATELY EXCITED MOTOR: In a separately excited motor, the connection of stator and rotor can be done using a different power supply. This enables the motor to be controlled from the shunt and its windings can be strengthened to generate flux.
PMDC: Permanent Magnet DC motor is one kind of DC motor which can be built with a permanent magnet to make the magnetic field necessary for the electric motor operation. PMDC motors are employed where speed control is not applicable.
DC COMPOUND MOTOR: A DC compound motor contain filed windings connected both in series and in parallel to the armature winding. It combines the operational characteristics of shunt and series DC motors, hence making it stable for all applications.
2) AC MOTOR
There are 3 types of ac motors: synchronous motor, asynchronous motor and induction motor.
SYNCHRONOUS MOTOR : The working of synchronous motors depends primarily on the supplied frequency and magnetic field. The field current in the stator rotates the armature at a stable speed synchronized with the AC frequency, here by constituting its high speed. Synchronous motors are employed where a precise and constant speed is required. The higher the accuracy level;, the more suitable these motors are for automation and robotics. 3-phase supply. The field current in the stator rotates in a stable speed based on the AC frequency. As well as the direction of rotation of the rotor depends on the similar speed of the stator current. The higher the accuracy level, the more suitable these motors are for automation and robotics.
INDUCTION MOTOR: The motor running at an asynchronous speed has the speed of the rotor lower than the corresponding magnitude of the magnetic field. This type of motor is known as an electro magnetic induction to convert electrical energy into mechanical energy. The rotor construction of these motors is based on two different designs: is known as an induction motor, and it’s alternately known as an asynchronous motor. An induction motor uses electromagnetic induction for converting electrical energy into mechanical energy. The rotor construction of these motors is based on two different designs, the squirrel cage and phase wound. Induction motors are the most commonly used motors as they have a simple construction and high efficiency.
3) SPECIAL PURPOSE MOTOR
The types of special purpose motors include linear induction motor and stepper motor.
STEPPER MOTOR: The stepper motor is a type of motor that offers step angle revolution, which is an alternative to stable revolution. In general, for any rotor, the whole revolution angle is 180 degrees. Stepper motors are widely used in plotters, circuit fabrication, process control tools, and other devices.
BRUSHLESS DC MOTOR: Brushless DC motors are good for applications which demand high performance within a limited space, better than the brushed DC and this is why they were first developed. These motors are less effective when compared with AC models. To facilitate the magnetic process within the lack of a commutator and a slip ring, an embedded controller is used.
HYSTERESIS MOTOR: Hysteresis motors are synchronous motors whose principle is based on hysteresis loss. This motor’s rotor can generate torque with the effect of eddy currents and hysteresis . These motors provide a stable and smooth process, similar to other synchronous motors, and are used in noiseless operation environment.
RELUCTANCE MOTOR: A reluctance motor is a type of single-phase synchronous motor, and this construction is quite similar with induction motor like cage type. The rotor of the motor is like a squirrel cage, and the stator includes sets of windings such as auxiliary and main windings. At the beginning of the motor’s operation, auxiliary winding creates the starting torque. It offers stable speed and level operation. These motors are commonly used in synchronization applications which include signal generators, recorders, etc.
UNIVERSAL MOTOR: This is a special kind of motor that works on single AC supply or DC supply. These motors are designed for high speed operation above 3500 rpm. They utilize alternating current at high-speed operation above 3500 rpm. They utilize alternating current at high – speed and direct current of similar voltage. There are different types of motors and their purpose is to be used in notion control applications.
Electric motors are used in a variety of applications such as:
- Batch process
- Fans and Blowers
- Machine tools
- Power Tools
Almost everything that moves uses an electric motor to accomplish its movement.