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

Inverse floaters, Normally, floater coupon rate moves in the same dir...

Normally, floater coupon rate moves in the same direction as the reference rate. That is, with an increase in the reference rate, the floater coupon rate also increases

Debentures, Debentures are also fixed income securities with a ...

Debentures are also fixed income securities with a specified interest rate. These securities have charge over the assets of the issuer. In contrast to

Describe personal financial management., Gary and Joyce Yau, both 30, last ...

Gary and Joyce Yau, both 30, last month bought their dream house in London, Ontario. The purchase price was $450,000 plus addition fees such as taxes, legal fees, administration fe

Causes of risks, Q. Causes of Risks 1) Wrong decision of what to invest...

Q. Causes of Risks 1) Wrong decision of what to invest in. 2) Wrong timing of investments. 3) Nature of instruments invested such as shares or bonds, chit funds, benefit

What is certified financial planner, Q. What is Certified Financial Planner...

Q. What is Certified Financial Planner? Certified Financial Planner (CFP) - Individuals who are trained to develop and implement financial plans for businesses, individuals and

Source documents of an accounting system, Source documents of an accounting...

Source documents of an accounting system: Source documents are those documents that identify the particular transaction that is being recorded.  They act as an internal control

Forward contracts, Forward Contracts: The origin of forward contracts i...

Forward Contracts: The origin of forward contracts is lost in history. Some authors suggest that, it was India where these contracts took birth, while some others suggest that

Rating elements and symbols, Rating Elements A rati...

Rating Elements A rating agency earns its reputation by assessing the client's operational performance, managerial competence, management and organiza

Price of the share as per gordon''s model, Considering the following inform...

Considering the following information, what is the price of the share as per Gordon's Model?  Details of the Company

Financial Management, Financial Management Initial Disclosures During the ...

Financial Management Initial Disclosures During the process of discussion and negotiation with the client with regard to the financial affairs and the manner of operations of the

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