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°.
Consider a currency swap in which the domestic party pays a fixed rate in foreign currency, the UK pounds sterling, and the counterparty pays a fixed rate in US Dollars. The not
An average should be: (a) vigorously defined, (b) easy to compute, (c) capable of simple interpretation, (d) dependent on all the observed values, (e) not unduly influenced by one
Woody Construction is considering a new 3-year expansion project that requires an initial fixed asset investment of $3.186 million. The fixed asset will be depreciated straight-lin
Different Cost of Capital with Changed Proportions: It is quite possible that the specific costs of capital of different sources may be affected by the amount of funds' raised and
What creates the APV capital budgeting framework useful for analyzing foreign capital expenditures? The APV framework is a value - additivity method. Since international projects
You are required to compute the value of both the firms using Net Income approach.
Cash Flow Statement Ratios: This ratio, which is defined as a percentage, compares a company's operating cash flow to its total sales or revenues, which provide investors an i
Group Activity An example of a budget can be seen below. After viewing the budget, identify the possible reasons for the variations. Budget - Jul / Dec 200X
An introduction to the principles of banking and finance It covers a broad variety of topics using an economic perspective and aims to give a general background to any student
Determine about the Sales agents Normally used for more effective sales and marketing activities for a product for example AVON (cosmetics) door to door agents in the UK. -
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