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

What do you mean by collateralized mortgage obligation, Q. What do you mean...

Q. What do you mean by Collateralized Mortgage Obligation? Collateralized Mortgage Obligation (CMO) - SECURITY whose cash flows equal the difference between cash flows of colla

What are the failure of mergers and takeovers, Failure of mergers and tak...

Failure of mergers and takeovers Failure of mergers and takeovers Poor strategic plan will result in slow or failed integration. Integra

#titleEvaluate alternative hedging strategies, Peak Inc. needs to order Can...

Peak Inc. needs to order Canadian raw materials to use in its production process. The Canadian exporter typically invoices Peak in Canadian dollars. Assume that the current exchang

What does weighted average cost of capital, What does the "weight" refer to...

What does the "weight" refer to in the weighted average cost of capital? The weight pass on to in weighted average cost of capital refers to the portion of the total capital in

What do you mean by pension funds, What do you mean by pension funds? ...

What do you mean by pension funds? Pension funds: Pension funds give retirement income (as the form of annuities) to workers covered through a pension plan. They get cont

Types of warrants, Types of Warrants The warrants can be classified int...

Types of Warrants The warrants can be classified into different types. They are: Detachable Warrants These warrants are issued with most debentures, like convertible o

Measuring interest rate risk , Investors are always interested in est...

Investors are always interested in estimating the price sensitivity of a bond to change in market interest rates. Let us study how prices change both in terms of

Show certificates of deposits, Q. Show Certificates of Deposits? Certif...

Q. Show Certificates of Deposits? Certificates of Deposits: Certificate of deposits is papers issued by banks acknowledging fixed deposits for a specified period of time. CPs i

Sinking fund provisions, Sinking fund provisions is a pool of funds s...

Sinking fund provisions is a pool of funds set aside to repay the debt. Under this, certain amount of money is kept aside every year form profit. It is then used

Primary market, Primary Market In an economy, at a given point of time, ...

Primary Market In an economy, at a given point of time, there will be people/entities called savers the surplus units, whose current income exceeds their current expenditure whi

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