Three-phase source voltages and phase sequence, Financial Management

Assignment Help:

Q. Three-phase source voltages and phase sequence?

The elementary three-phase, two-pole generator shown in Figure has three identical stator coils (aa, bb, and cc) of one or more turns, displaced by 120° in space from each other. The rotor carries a ?eld winding excited by the dc supply through brushes and slip rings. When the rotor is driven at a constant speed, voltages of equal amplitude but different phase angle will be generated in the three phases in accordance with Faraday's law. Each of the three stator coils constitutes one phase of this single generator. If the ?eld structure is so designed that the ?ux is distributed sinusoidally over the poles, the ?ux linking any phase will vary sinusoidally with time, and sinusoidal voltages will be induced in the three phases. These three induced voltage waves will be displaced by 120 electrical degrees in time because the stator phases are displaced by 120° in space. When the rotor is driven counterclockwise, Figure (a) shows the wave forms and Figure (b) depicts the corresponding phasors of the three voltages. The time origin and the reference axis are chosen on the basis of analytical convenience. In a balanced system, all three phase voltages are equal in magnitude but differ from each other in phase by 120°. The sequence of voltages in Figure 4.1.2(b), corresponding to that of Figure (a), is known as the positive sequence (a-b-c). On the other hand, if the rotor is driven clockwise, then Figure (c) shows the corresponding phasor of the three voltages; the sequence of voltages in Figure (c) is known as negative sequence (a-c-b). Notice that in positive sequence ¯Ebb lags ¯Eaa by 120°, and ¯Ecc lags ¯Ebb by 120°; in negative sequence, however, ¯ Ecc lags ¯ Eaa by 120°, and ¯ Ebb lags ¯ Ecc by 120°.

1933_Three-phase source voltages and phase sequence.png


Related Discussions:- Three-phase source voltages and phase sequence

Example on modigliani and miller approach, Q. Example On modigliani and mil...

Q. Example On modigliani and miller approach? The subsequent is the data regarding two companies X and Y belonging to the same risk class: Company X

Conversion premium , The amount by which the market price exceeds the...

The amount by which the market price exceeds the conversion value or the investment value is called as the premium.

Analysis on the stocks, Yellow: is the company which their stock performanc...

Yellow: is the company which their stock performance was forecasted by analyst Blue: is the name of the company which made the recommendation by the analyst who work for it R

Virements, what is the relevance of virements to public sector accounting

what is the relevance of virements to public sector accounting

Beta, Definition of 'Beta' A measure of the volatility or systematic ri...

Definition of 'Beta' A measure of the volatility or systematic risk of a security or a portfolio in difference to the market as a whole. Beta is needed in the capital asset pri

efficient variance reduction, Assume we are in the midst of the financial ...

Assume we are in the midst of the financial crisis in October 2008. Your firm is considering the purchase of a 10 year put option on the S&P 500 Index. You are analyzing the pricin

Define intermediation, Define intermediation . The monetary system mak...

Define intermediation . The monetary system makes it possible for deficit and surplus economic units to come together exchanging funds for securities to their mutual benefit.

Global bonds, These are bonds which are offered within the euro marke...

These are bonds which are offered within the euro market and several other markets simultaneously. Unlike Eurobonds, global bonds can be issued in the same curren

Risk-bearing economies of scale, a) Product portfolio refers to the diversi...

a) Product portfolio refers to the diversity of the different product lines produced by a business. In this case, Mattel's product portfolio includes: board games, toy cars, cuddly

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