Table of Contents
The stator and rotor windings of an induction machine possess resistances and leakage reactances just like the resistances and leakage reactances of the primary and secondary windings of a transformer. Due to the above similarities, the induction machine is referred to as a generalized transformer.
Why an induction machine is called generalized transformer?
Induction motor is a generalized transformer. In transformer the flux produced is time alternating and not rotating. There is no air gap between primary and secondary of transformer where as there is a distinct air gap between stator and rotor of motor which gives mechanical movability to motor.
Can an induction machine be used as a transformer?
An induction motor is a well-known device which works on the principle of transformer. That is, when an EMF is supplied to its stator, then as a result of electromagnetic induction, a voltage is induced in its rotor. So an induction motor is said to be a transformer with rotating secondary.
Which motor is similar to that of a transformer Why?
The principle of an induction motor is similar to that of a transformer. The main difference is that the secondary of an induction machine is rotating and the secondary of a transformer is fixed.
Which is the best starting method for induction motor?
Induction Motor Starting Methods Direct On Line Starter. Star-Delta Starter. Auto Transformer Motor Starting. Rotor Resistance Starter. Introduction.
What is the difference between induction motor and transformer?
A transformer transfers electrical power from one circuit to another without changing the supply frequency, i.e. it only step-up or step-down the level of voltage and current, whereas induction motor converts electrical power into mechanical power.
What is the power factor of induction generator?
in most induction generator applications, power factor correction in the form of capacitance will be required to raise the induction generator’s operating power factor up to the area of 0.90 to 0.95 lagging. (Power factor correction information is available from companies that sup- ply industrial capacitor banks.).
What is the emf equation of a transformer?
Therefore, RMS value of emf per turn = 1.11 x 4f Φm = 4.44f Φm. This is called the emf equation of transformer, which shows, emf / number of turns is same for both primary and secondary winding. For an ideal transformer on no load, E1 = V1 and E2 = V2 .
Is a transformer a motor?
A motor is an extended version of a transformer. Here we can introduce the analogy between a transformer and a motor that is a motor is like a transformer with a moving secondary. The primary that is not moving is called stator and the secondary that is moving is called rotor.
What is the working principle of induction motor?
Working Principle of Induction Motor The motor which works on the principle of electromagnetic induction is known as the induction motor. The electromagnetic induction is the phenomenon in which the electromotive force induces across the electrical conductor when it is placed in a rotating magnetic field.
What is difference between DC motor and induction motor?
D.C wound field motors are constructed with brushes and a commutator, which add to the maintenance, limit the speed and usually reduce the life expectancy of brushed D.C. motors. A.C. induction motors do not use brushes; they are very rugged and have long life expectancies. The final basic difference is speed control.
What does a transformer change?
Transformers change the voltage of the electrical signal coming out of the power plant, usually increasing (also known as “stepping up”) the voltage. Transformers also reduce (“step down”) the voltage in substations, and as distribution transformers.
What are types of induction motor?
Types of Induction Motors Split Phase Induction Motor. Capacitor Start Induction Motor. Capacitor Start and Capacitor Run Induction Motor. Shaded Pole Induction Motor.
Why starter is used in induction motor?
Let us study in detail why starter is required for an induction motor. At starting time, the speed of the motor is zero and slip is at its maximum i.e. unity. So magnitude of the rotor induced emf is very large at start.
What are the starting methods of induction motor?
Methods of Starting Three Phase Induction Motors. Direct-on-Line Starter (DOL) Star Delta starter. Auto-Transformer Starting. Rotor Resistance Starter. Review.
What are the merits and demerits of induction motor?
Induction motors always operate under lagging power factor and during light load conditions they operate at very worst power factor (0.2 to 0.4 lagging). Some of the disadvantages of poor power are increase in I2R losses in the system, reduction in the efficiency of the system.
What are parts of transformer?
There are three basic parts of a transformer: an iron core which serves as a magnetic conductor, a primary winding or coil of wire and. a secondary winding or coil of wire.
What are the applications of induction motors?
The single-phase induction motors are used in low power applications. These motors are widely used in domestic and industrial applications.Three-Phase Induction Motor: Lifts. Cranes. Hoists. Large capacity exhaust fans. Driving lathe machines. Crushers. Oil extracting mills. Textile and etc.
What is the efficiency of induction motor?
Efficiency of three-phase induction motors can vary from 85% to 96%. See the chart below for torque vs. slip. Induction motors of 50-100 HP for industrial applications vary in weight from 700 to almost 1,000 lbs.
What are the types of induction generator?
Generally, there are two types of induction generators widely used in wind power systems – Squirrel-Cage Induction Generator (SCIG) and Doubly-Fed Induction Generator (DFIG).
Is induction generator self excited?
An induction generator is not a self-excited machine. Therefore in order to develop the rotating magnetic field, it requires magnetizing current and reactive power.
What are the main parts of 3 phase induction motor?
The stator of the three-phase induction motor consists of three main parts : Stator frame, Stator core, Stator winding or field winding.
What is the formula for calculating emf?
If we know the resulting energy and the amount of charge passing through the cell. It is the simplest way to calculate the EMF. The electromotive force of cell.The Formula for Calculating the EMF. \varepsilon electromotive force E the energy in the circuit Q Charge of the circuit.
How do you calculate the emf?
The emf is equal to the work done on the charge per unit charge (ϵ=dWdq) when there is no current flowing. Since the unit for work is the joule and the unit for charge is the coulomb, the unit for emf is the volt (1V=1J/C).
What is a motional emf?
An emf induced by motion relative to a magnetic field is called a motional emf. This is represented by the equation emf = LvB, where L is length of the object moving at speed v relative to the strength of the magnetic field B.
