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

Dividend policy, DIVIDEND POLICY Dividends provide the portion of a fi...

DIVIDEND POLICY Dividends provide the portion of a firm's net earnings which are paid out to the shareholders. the objective of financial management of maximizing the share

What is the irr of the project, QUESTION Part A: 1. Nev Plc is consi...

QUESTION Part A: 1. Nev Plc is considering to invest in a machine to manufacture a new line of umbrellas. The following data has been assembled in respect of the investment:

SES, Scenario: You are still a consultant for the Excellent Consulting Grou...

Scenario: You are still a consultant for the Excellent Consulting Group. You have completed the first assignment, developing and testing a forecasting method based on linear regres

Determine have mergers affected competition, Have mergers affected competit...

Have mergers affected competition? A: Federal Reserve data depict that measured on the local level, where competition occurs; markets have in fact experienced more banking comp

Put option, Put Option This is a right which is granted in exchange for...

Put Option This is a right which is granted in exchange for an agreed-upon sum to sell property. Options are mostly used frequently in securities transactions it also used stoc

Firms operation and financing decision, Q. Firms operation and financing de...

Q. Firms operation and financing decision? Firms operation and financing decision risks or the variability of returns also results for the decision make within the company. Ris

Financial ratio , Ratio Calculation:   A 'Financial Ratio' is an ind...

Ratio Calculation:   A 'Financial Ratio' is an index that relates two accounting numbers and is obtained by dividing one number by the other. Various Ratios are - 1. L

Stock valuation, I just purchased a stock that would pay the dividends of t...

I just purchased a stock that would pay the dividends of the first four years as D1 = $0.65, D2 = $0.74, D3 = $0.79, D4 = $0.84. I also told that the dividends would grow continual

International strategic management, undertake a critical review of the curr...

undertake a critical review of the current academic literature to determine the reasons for benefits of and the costs to companies of cross listing.

Working capital management, Q. Working capital management? Every busine...

Q. Working capital management? Every business needs funds for the two purposes for its establishments and to carry out day to day operations. Long terms funds are required to c

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