Equivalent circuit of a polyphase induction machine, Electrical Engineering

Assignment Help:

Equivalent Circuit of a Polyphase Induction Machine

The inductionmachinemay be regarded as a generalized transformer inwhich energy is converted and electric power is transferred between stator and rotor, along with a change of frequency and a flow of mechanical power. At standstill, however, the machine acts as a simple transformer with an air gap and a short-circuited secondary winding. The frequency of the rotor-induced emf is the same as the stator frequency at standstill. At any value of the slip under balanced steady-state operation, the rotor current reacts on the statorwinding at the stator frequency because the rotating magnetic fields caused by the stator and rotor are stationary with respect to each other.

328_Equivalent Circuit of a Polyphase Induction Machine.png

The induction machine may thus be viewed as a transformer with an air gap and variable resistance in the secondary; the stator of the induction machine corresponds to the transformer primary, and the rotor corresponds to the secondary. For analysis of the balanced steady state, it is sufficient to proceed on a per-phase basis with some phasor concepts; so we will now develop an equivalent circuit on a per-phase basis. Only machines with symmetrical polyphase windings excited by balanced polyphase voltages are considered. As in other discussions of polyphase devices, let us think of three-phase machines as wye-connected, so that currents are always line values and voltages are always line-to-neutral values (on a per-phase basis).

The resultant air-gap flux is produced by the combined mmfs of the stator and rotor currents. For the sake of conceptual and analytical convenience, the total flux is divided into a mutual flux (linking both the stator and the rotor) and leakage fluxes, represented by appropriate reactances.


Related Discussions:- Equivalent circuit of a polyphase induction machine

Analog averaging system, Consider the analog averager where x(t) is the inp...

Consider the analog averager where x(t) is the input and y(t) is the output. (a)   Find the impulse response h(t) of the average.  Is this system causal? (b)   Let x(t)

Zero flag - registers , Zero Flag - Registers If the  result of any  a...

Zero Flag - Registers If the  result of any  arithmetical  or logical  operation in the accumulator  is zero i ,e  all the bits  of accumulator  ( with  some exceptions )  are

Determine the shaft power output, Determine the shaft power output: A ...

Determine the shaft power output: A 6-pole, 50 Hz, 3-phase induction motor running on full load develops a useful torque of 180 Nm when the rotor emf frequency is 2 Hz. Determ

Lc circuits, L=0.0053nH, C=15µF find the operating frequency of series LC c...

L=0.0053nH, C=15µF find the operating frequency of series LC circuit. What factors decides capacitance ..

Find kfm for the modulator using carsons rule, Q. A commercial FMstation br...

Q. A commercial FMstation broadcasts a signal with 180-kHz bandwidth when |f(t)|max = 2 V. Find kFM for the modulator if the spectral extent of f (t) is 30 kHz, by using Carson's r

Filtering, Filtering  (i) Write an m-file "mymedian.m" which will ta...

Filtering  (i) Write an m-file "mymedian.m" which will take an image and filter size and perform median filtering. Display input and output image. Use  help median fun

Determine the electromagnetic torque developed, Q. A dc series motor, with ...

Q. A dc series motor, with a design constant K a = 40 and flux per pole of 46.15 mWb, operates at 200 V while taking a current of 325 A. The total series-field and armature-circui

Data transmission in bus topology, Q. Data transmission in Bus Topology ? ...

Q. Data transmission in Bus Topology ? Bus Topology:This topology shares a single path or link way among all users. This common single path way is called bus. In this topology,

Earth leakage-earthing, Earth Leakage : Earth leakage takes place when, th...

Earth Leakage : Earth leakage takes place when, through some fault in an appliance or its connections. Electric current escapes to earth i.e. the body of the appliance become 'liv

What is txd, What is TXD? TXD- Transmitter Data Output This output p...

What is TXD? TXD- Transmitter Data Output This output pin carries serial stream of the transmitted data bits by with other information like start bit, stop bits and priority

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd