Induction Motor Construction

The relative speed between stator RMF and rotor conductors causes an induced emf in the rotor conductors, according to the Faraday's law of electromagnetic induction. The rotor conductors are short circuited, and hence rotor current is produced due to induced emf. That is why such motors are called as induction motors.

What is the construction of 3 phase induction motor?

It consists of a steel frame which encloses a hollow cylindrical core. The core of the three phase induction motor is made up of thin laminations of silicon steel to reduce the eddy current and hysteresis losses.

What are the main parts of induction motor?

Components of an Induction Motor An induction or asynchronous motor is composed of two main components: the stator and rotor. The stator consists of the outer windings or magnets and is stationary. The stator is stationary. The rotor is the inner core and is what actually rotates in the motor.

What is construction of single-phase induction motor?

Single phase induction motors generally have a construction similar to that of a three phase motor: an ac windings is placed on the stator, short-circuited conductors are placed in a cylindrical rotor. The significant difference is, of-course, that there is only a single phase supply to the stator.

Why it is called induction motor?

The asynchronous nature of induction motors creates slip—the difference between the rotating speed of the shaft and the speed of the motor's magnetic field—which allows for increased torque. These motors are powered at the stator, while the rotor induces current—hence the name “induction” motor.

Why is it called 3-phase induction motor?

A 3 phase induction motor derives its name from the fact that the rotor current is induced by the magnetic field, instead of electrical connections. The operating principle of a 3 phase induction motor is based on the production of r.m.f.

What are the 3 types of 3-phase motors?

Three-phase AC motors can be divided into three general types: squirrel-cage, wound-rotor and synchronous.

What is induction motor used for?

They are used for loads that requires speed control. Typical applications of wound rotor or slip ring induction motors are crushers, plunger pumps, cranes & hoists, elevators, compressors and conveyors.

What is slip speed?

The difference between stator magnetic field speed or synchronous speed and actual speed of the motor is known as slip speed.

What are the types of induction motor?

There are three basic types of small induction motors: split-phase single-phase, shaded-pole single-phase, and polyphase. In two-pole single-phase motors, the torque goes to zero at 100% slip (zero speed), so these require alterations to the stator such as shaded-poles to provide starting torque.

What's a 3-phase motor?

Three-phase motors are a type of AC motor that is a specific example of a polyphase motor. These motors can be either an induction motor (also called an asynchronous motor) or a synchronous motor. The motors consist of three main components – the stator, the rotor, and the enclosure.

What is slip in induction motor?

“Slip” in an AC induction motor is defined as: As the speed of the rotor drops below the stator speed, or synchronous speed, the rotation rate of the magnetic field in the rotor increases, inducing more current in the rotor's windings and creating more torque. Slip is required to produce torque.

What is torque of motor?

Torque: The torque output of a motor is the amount of rotational force that the motor develops. The torque of a small electric motor is commonly measured in either inch pounds (in-lbs), Newton meters (N-m) or other directly converted units of measure.

What is speed control of induction motor?

Induction motor speed control is a process of manipulating currents in an induction motor to regulate speed. While often used in fixed frequency applications, induction motors are popular for variable frequency applications such as industrial drives and electric vehicles.

What is called synchronous speed?

Definition of synchronous speed : a definite speed for an alternating-current machine that is dependent on the frequency of the supply circuit because the rotating member passes one pair of poles for each alternation of the alternating current.

What is DOL starter?

Direct on line (DOL) motor starting is when a motor is started at full load, with full line voltage applied to motor terminals. As this causes the motor to draw a large amount of current, it is only suitable for motor powers up to 4Kw, with a maximum motor size of 10Kw connected this way.

What is the voltage of 3-phase?

In a single-phase power supply system, the voltage may reach up to 230 Volts. But on a three-phase connection, it can carry a voltage of up to 415 Volts.

What is principle of three-phase induction?

A 3 phase induction motor derives its name from the fact that the rotor current is induced by the magnetic field, instead of electrical connections. The operating principle of a 3 phase induction motor is based on the production of a rotating magnetic field (r.m.f.).

What is stator and rotor?

The rotor is the rotating part of a machine. In electrical motors or generators, the whole linear synchronously rotating part of the machine is termed the rotor. The stator is the non-moving, fixed counterpart in a machine.

What are different types of starter?

Types of Motor Starters

• Manual Starters.
• Magnetic Motor Starters.
• Direct-On-Line Starter.
• Rotor Resistance Starter.
• Stator Resistance Starter.
• Auto Transformer Starter.
• Star Delta Starter.
• NEMA Rating.