Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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°.
Define operating cycle and long and short operating cycle? Use of operating cycle? Can someone give me assistance on these questions??
What is the rational for having different types of security
1. Calculate the compound average annual growth rate in sales and profit after tax
operating cycle of a vegetable growing business
Identify whether the following items belong on the income statement or the balance sheet. a. Interest Expense IS l. Cash BS b. Prefer
Explain the term- Maturities Debentures are sometimes grouped by length of time till maturity that existed on the date debenture was first issued. Money Market Securities matu
At times, companies accuse investors of performing credit sales that they make their quotations fall. Is that true? It is true: there are companies that accuse investors who pe
Insurance companies The primary purpose of insurance companies is to protect individuals and firms known as policy-holders from adverse events. Insurance companies receive prem
A company borrows $1,500,000 at LIBOR plus a lending margin of 1.25 percent per year on a six-month rollover basis from a London bank. If six-month LIBOR is 4 ½ % over the first s
COST OF CAPITAL A project's Cost of Capital is the smallest amount of acceptable rate of return/required rate of return on funds committed to the project. It is a compensation
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd