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

Gordon''s dividend capitalization method, formula and explanation for Gordo...

formula and explanation for Gordon''s dividend capitalization method

Types of dividend policy, TYPES OF DIVIDEND POLICY 1. Regular dividen...

TYPES OF DIVIDEND POLICY 1. Regular dividend policy: Payment of dividend at standard rate is known as regular dividend policy. 2. Stable dividend policy: Payment of fix

Show the advantages of adjusted discount rate, Q. Show the Advantages of ad...

Q. Show the Advantages of adjusted discount rate? Advantages:- (1) It is simple to understand and simple to calculate. (2) The risk premium rate comprised in the risk adj

Explain about centralised treasury function, Q. Explain about Centralised t...

Q. Explain about Centralised treasury function? Treasury departments are usually a feature of larger companies than Frantic although it is perhaps beneficial to consider the be

Interpretations of activity ratio''s, Activity Ratio's   RT:        ...

Activity Ratio's   RT:           The Receivables Turnover ratio is the ratio between sales to accounts receivables. This says exactly how fast a company can collect on the s

What is the tolerable error, What is the Tolerable error In addition t...

What is the Tolerable error In addition to looking at material differences individually the auditor must list all the differences (material or not) and consider in total wheth

Case study.., This case has been framed in order to test the skills in eval...

This case has been framed in order to test the skills in evaluating a credit request and reaching a correct decision. Perluence International is large manufacturer of petroleum and

Credit policy, What is the Credit Policy? Describe please.

What is the Credit Policy? Describe please.

Historical inflation and stock value experience, Historical Inflation and S...

Historical Inflation and Stock Value Experience The experimental evidence denies the status of stocks as a good hedge against inflation. A study conducted by Ibbotson and Brins

How cash budget and capital budget relate to pro forma, Explain how the cas...

Explain how the cash budget and the capital budget relate to pro forma financial statements. The cash budget depicts the projected flow of cash in and out of the firm for fixed

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