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

State about the nick leeson and barings, Nick Leeson and Barings Leeson...

Nick Leeson and Barings Leeson was the trader who managed to bring about the collapse of Barings Bank in 1995. The main reason he was able to do this was because there was a ce

Risk-free rate, Assume you manage a $4.42 million fund that having of four ...

Assume you manage a $4.42 million fund that having of four stocks with the following investments: Stock Investment Beta A

WEALTH.., What is the fastest way to be rich?

What is the fastest way to be rich?

Explain traditional method of measurement, Q. Explain Traditional Method of...

Q. Explain Traditional Method of Measurement? Computation of yield to measure a financial asset's return is the simplest and oldest technique of measurement. Yield can be find

Leverage, evaluate the importance of leverage in a small scale company

evaluate the importance of leverage in a small scale company

Sophisticated methods of mortgage backed security valuation, MBS ...

MBS are the most complicated securities that are sensitive to interest rates. The factors that affect the price of MBS are varied and most of th

Spot transaction hedge/Money market hedge, There are three parts to this qu...

There are three parts to this question. Please answer all parts. The Chicken Company, a company with headquarters in Switzerland, has a receivable of one million euro, which it wil

Cyclical variation in time series analysis, Cyclical Variation By cycli...

Cyclical Variation By cyclical variations, we refer to the long-term movement of the variable about the trend line. Therefore, does the movement of the actual series about a tr

Find out the interest rate parity is currently holding, Presently, the spot...

Presently, the spot exchange rate is $1.50/£ and the three-month forward exchange rate is $1.52/£. The three-month interest rate is 8.0% per year in the U.S. and 5.8% per year in t

#WALTOR''S MODEL., CAPITALISATION RATE=0.01 EARNINGS PER SHARE(E)=10 ASSUME...

CAPITALISATION RATE=0.01 EARNINGS PER SHARE(E)=10 ASSUME RATE OF RETURNS ON INVESTMENTS (R):15

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