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When a machine has more than two poles, only a single pair of poles needs to be considered because the electric, magnetic, and mechanical conditions associated with every other pole pair are repetitions of those for the pole pair under consideration. The angle subtended by one pair of poles in a P-pole machine (or one cycle of flux distribution) is defined to be 360 electrical degrees,or2π electrical radians. So the relationship between the mechanical angle m and the angle in electrical units is given by
because one complete revolution has P/2 complete wavelengths (or cycles). In view of this relationship, for a two-polemachine, electrical degrees (or radians)will be the same asmechanical degrees (or radians).
In this section we set out to show that a rotating field of constant amplitude and sinusoidal space distribution of mmf around a periphery of the stator is produced by a three-phase winding located on the stator and excited by balanced three-phase currents when the respective phase windings are wound 2π/3 electrical radians (or 120 electrical degrees) apart in space. Let us consider the two-pole, three-phase winding arrangement on the stator shown in Figure.
The windings of the individual phases are displaced by 120 electrical degrees from each other in space around the air-gap periphery. The reference directions are given for positive phase currents. The concentrated full-pitch coils, shown here for simplicity and convenience, do in fact represent the actual distributed windings producing sinusoidal mmf waves centered on the magnetic axes of the respective phases. Thus, these three sinusoidal mmf waves are displaced by 120 electrical degrees from each other in space. Let a balanced three-phase excitation be applied with phase sequence a-b-c, ia = I cos ωs t ; ib = I cos(ωs t - 120°); ic = I cos(ωs t - 240°) where I is the maximum value of the current, and the time t = 0 is chosen arbitrarily when the a-phase current is a positive maximum. Each phase current is an ac wave varying in magnitude sinusoidally with time. Hence, the corresponding component mmf waves vary sinusoidally with time. The sum of these components yields the resultant mmf.
(a) Design a 6-bit R-2 R ladder D/A converter. (b) For V ref = 10 V, find the maximum output voltage. (c) Determine the output voltage increment. (d) If the output voltag
..Explain mixedd storage oscilloscope with neat diagram,
Large scale integration chips have between (A) Less than 10 components. (B) 10 and 100 components. (C) 100 and 1000 components. (D) More than 1000 componen
Q. Let a(t) = [1 + m A x(t)] and x(t) = cos 2πf m t, f m c , and x c (t) = A(t) cos 2πfct . (a) With m A =1, sketch one full period of the AM wave and draw the envelope by co
The block diagram of Figure is a functional representation of a type of digital control system, in which G and H serve the same function as in any feedback system. Note that the er
Q. Explain the application of clippers. There are numerous clipper applications. In general clippers are used to perform one of the following two functions: · Changing the s
What are the 8086 interrupt types? Dedicated interrupts Type 0: Divide by zero interrupt Type 1: Single step interrupt Type 2:Non maskable interrupt Type 3: Breakpo
3-phase 3 wire meter with CT and MD It is exactly such as 3-phase 4 wire meter and works on the similar principle. It is also used in the similar way and under the similar cir
I have to make assignment of about the topic Magnetism and magnetic materials. I don''t know how I will prepare this assignment. Please give me some instructions about this.
Q. Illustrate the Simplex Transmission? Simplex Transmission Data in a simplex channel is always one way. Simplex channels aren't often used as it is not possible to send ba
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