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

Payback period, Can some one tell me how to calculate payback period and wh...

Can some one tell me how to calculate payback period and which formula i used to calculated payback period? Explain!!!!

What to do to maximise profits of the company, What to do to maximise profi...

What to do to maximise profits of the company If you want to maximise profits, there are only two methods to do it. Either you decrease your expenses (also known as costs) or y

Perpetual-floating rate bonds-index and linked bonds, Explain the following...

Explain the following term: Perpetual bonds, Floating rate bonds, Index-linked bonds and Callable bonds. Perpetual bonds (also termed as consols) are never mature. This

Profit & loss account, waht are the basic functions of profit & loss accoun...

waht are the basic functions of profit & loss account

Bank credit, Definition of 'Bank Credit': The amount of credit availab...

Definition of 'Bank Credit': The amount of credit available to a business or individual from the banking system. It is the aggregate of the amount of funds financial instituti

Explain the competitive benchmarking, Explain the Competitive Benchmarking ...

Explain the Competitive Benchmarking Healthcare services or Hospital are compared to rival 'competition 'in the same industry for instance methods of patient care and levels o

Introduction to fixed income portfolio management strategies, Investors use...

Investors use two management strategies to manage their fixed income portfolios. They adopt either active management strategy or passive management strategy. A

Determinants of working capital, Q. Determinants of Working Capital? D...

Q. Determinants of Working Capital? Determinants of Working Capital: - The working capital necessity is determined by a large number of factors but generally the following fa

Show gross vs net working capital, Q. Show Gross Vs net working capital? ...

Q. Show Gross Vs net working capital? The distinction between the gross working capital or the net working capital does not in any way undermine the relevance of the concepts o

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