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Top 100+ Induction Motors Interview Questions And Answers - May 31, 2020

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Top 100+ Induction Motors Interview Questions And Answers

Question 1. What Is An Induction Motor?

Answer :

An induction motor (IM) is a type of asynchronous AC motor wherein strength is provided to the rotating tool via electromagnetic induction.

Question 2. What Is An Electric Motor?

Answer :

An Electric Motor converts electrical strength to mechanical power in its rotor.

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Question 3. How To Supply Power To Rotor?

Answer :

In a DC motor this electricity is provided to the armature at once from a DC source, whilst in an AC motor this energy is induced in the rotating tool.

Question 4. Why An Induction Motor Sometimes Called Rotating Transformer?

Answer :

An induction motor is on occasion referred to as a rotating transformer due to the fact the stator (stationary element) is largely the number one facet of the transformer and the rotor (rotating part) is the secondary facet.

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Question 5. Who Invented Induction Motor?

Answer :

Nikola Tesla.

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Question 6. What Is The Basic Difference Between Synchronous Motor And An Induction Motor?

Answer :

The primary distinction between an induction motor and a synchronous AC motor is that in the latter a present day is furnished onto the rotor. This then creates a magnetic area which, through magnetic interaction, hyperlinks to the rotating magnetic field within the stator which in turn reasons the rotor to turn. It is called synchronous because at constant nation the velocity of the rotor is the same as the speed of the rotating magnetic discipline in the stator.

Question 7. Why Stator Windings Are Arranged Around The Rotor?

Answer :

the induction motor does no longer have any direct deliver onto the rotor; alternatively, a secondary contemporary is caused inside the rotor. To attain this, stator windings are organized around the rotor so that when energised with a polyphase deliver they create a rotating magnetic area sample which sweeps past the rotor. This changing magnetic area sample can set off currents within the rotor conductors. These currents engage with the rotating magnetic subject created by using the stator and the rotor will flip.

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Question 8. Why The Speed Of The Physical Rotor And The Speed Of The Rotating Magnetic Field In The Stator Must Be Different?

Answer :

The pace of the bodily rotor and the velocity of the rotating magnetic area inside the stator have to be extraordinary, or else the magnetic field will now not be transferring relative to the rotor conductors and no currents may be brought on.

Question nine. What Is The Slip?

Answer :

This distinction among the velocity of the rotor and velocity of the rotating magnetic discipline inside the stator is called slip. It is unitless and is the ratio among the relative speed of the magnetic field as seen through the rotor to the rate of the rotating field. Due to this an induction motor is sometimes referred to as an asynchronous system.

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Question 10. How Many Types Of Induction Motor ?

Answer :

Based on kind of phase deliver:

Three phase induction motor (self starting in nature)
Single section induction motor (now not self starting)
Other:

Squirrel-cage induction motor
Slip ring induction motor
Question eleven. What Is A Stator?

Answer :

The stator consists of wound 'poles' that deliver the supply present day that induces a magnetic field in the conductor. The wide variety of 'poles' can range among motor kinds however the poles are always in pairs (i.E. 2, 4, 6, and so on.).

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Question 12. How Many Types Of Rotor Are There?

Answer :

There are two sorts of Rotors:

Squirrel Cage rotor.
Slip Ring rotor.
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Question thirteen. What Techniques Is Used To Produce A Desired Speed?

Answer :

The most commonly used method is Pulse Width Modulation wherein a DC sign is switched on and off very unexpectedly, generating a chain of electrical pulses to the inductor windings.

Question 14. What Is The Difference Between Dc Motors And The Induction Motors?

Answer :

The induction motor has no brushes and is straightforward to govern, many older DC motors are being replaced with induction cars and accompanying inverters in business programs.

Question 15. How An Induction Motor Is Started? Why The Starter Is Used?

Answer :

When the motor is started out, the slip is same to 1 because the rotor speed is zero, so the prompted emf in the rotor is big. As a result, a totally excessive current flows via the rotor. This is much like a transformer with the secondary coil brief circuited, which reasons the primary coil to draw a excessive cutting-edge from the mains. Similarly, whilst an induction motor begins, a totally high present day is drawn by the stator, on the order of 5 to nine times the entire load contemporary. This excessive modern-day can harm the motor windings and because it reasons heavy line voltage drop, other appliances related to the identical line may be suffering from the voltage fluctuation. To keep away from such effects, the starting contemporary need to be limited. A soft start starter is a tool which limits the beginning modern by means of supplying decreased voltage to the motor. Once the rotor speed will increase, the overall rated voltage is given to it.

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Question sixteen. What Is A Rotor?

Answer :

The rotor is the non-stationary part of a rotary electric motor or alternator, which rotates due to the fact the wires and magnetic subject of the motor are arranged in order that a torque is developed about the rotor's axis. In a few designs, the rotor can act to serve as the motor's armature, across which the enter voltage is provided. The stationary a part of an electric motor is the stator. A commonplace trouble is referred to as cogging torque.

Question 17. What Is Commutator?

Answer :

A commutator is an electrical transfer that periodically reverses the present day path in an electric motor or electric generator. A commutator is a not unusual characteristic of direct contemporary rotating machines. By reversing the modern course within the moving coil of a motor's armature, a consistent rotating pressure (torque) is produced. Similarly, in a generator, reversing of the coil's connection to the external circuit produces unidirectional modern within the circuit. The first commutator-kind direct modern-day device became constructed by way of Hippolyte Pixii in 1832.

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Question 18. What Is An Armature?

Answer :

An armature is one of the two important electrical additives of an electromechanical device--a motor or generator. The other is the sphere winding, subject magnet. The function of the "subject" aspect is genuinely to create a magnetic subject (magnetic flux) for the armature to engage with, so this component can incorporate both everlasting magnets, or electromagnets formed by means of a undertaking coil. The armature, in contrast, need to deliver contemporary so it's far constantly a conductor or a conductive coil, orientated regular to each the field and to the direction of motion, torque (rotating system), or force (linear system). The armature's role is two-fold: (a) to hold present day crossing the sphere, consequently developing shaft torque (in a rotating system) or pressure (in a linear gadget), and (b) to generate an electromotive force ("EMF").

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Question 19. What Is A Cogging Torque?

Answer :

Cogging torque of electrical automobiles is the torque due to the interaction among the permanent magnets of the rotor and the stator slots of a Permanent Magnet (PM) device. Also termed as detent or 'no-cutting-edge' torque, it's miles an undesirable factor for the operation of any such motor. It is specifically distinguished at decrease speeds, with the symptom of jerkiness.




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