The three-phase alternator, Electrical Engineering

Assignment Help:

The Three-phase alternator

In this case, three separate sets of coils are wound on the stator and connected to produce three separate outputs. Because of the physical displacement of the coils around the stator, the outputs will have different phases with respect to each other. Three-phase systems are common even when DC outputs are required (e.g. electric alternators to charge a car battery) because of the torque reaction problem mentioned above. The AC output is rectified with a set of six diodes mounted in a single pack (two diodes are needed to rectify each phase).

A  two-pole, three-phase alternator is shown in the diagram below. Stator coils AB belong to phase 1, coils CD to phase 2 and coils EF to phase 3. Each pair of coils are connected  in series and their outputs add (e.g. A and B are connected in series to  produce  phase  1  output).  Notice  it  is two-pole because there are only two poles (i.e. one pole pair) on the rotor. The frequency of each phase output is therefore equal to the rotational speed of the rotor.

1357_The Three-phase alternator.png

 

 

 

Unlike the single-phase  alternator, it turns out  that  the  torque  required  to  drive  a three-phase alternator is constant, with no pulsating component. This is an important advantage.The figure below shows the arrangement for   a     multipole   three-phase   alternator. Again, coils A&B, C&D and E&F are connected in series to three differnet outputs, each with a phase shift  of 120° apart (because of the physical arrangement of the coils on the stator).

1646_Three-phase alternator.png

 

 


Related Discussions:- The three-phase alternator

Explain the theory of thermal runaway, Q. Explain the theory of thermal run...

Q. Explain the theory of thermal runaway?           The maximum average power Pdmax which a transistor can dissipate depends upon the transistor construction and may lie in the

Electron, Electron congratulations

Electron congratulations

What is meant by blanking, a. Explain the following terms: (6) (i) Persi...

a. Explain the following terms: (6) (i) Persistence of vision (ii) Flicker in motion pictures b. What is meant by blanking? What is the need of blanking pulses? Compare th

Difference between and and test instructions, Mention how do the AND & T...

Mention how do the AND & TEST instructions differ in their functionality AND: Changes the destination operand while performs the AND operation and. TEST: This ins

How do you find the insulation resistance of transformer, Q. How do you cal...

Q. How do you calculate the insulation resistance of transformer and what is the minimum value? Ans. The insulation resistance of the transformer will be calculated by using

Explain demodulation of dsb, Q. Explain Demodulation of DSB? Demodulati...

Q. Explain Demodulation of DSB? Demodulation of DSB SC AM signals requires a synchronous demodulator, which is also known as coherent or synchronous detector. That is, the demo

Calculate the power transferred across the air gap, A three-phase, 5-hp, 22...

A three-phase, 5-hp, 220-V, six-pole, 60-Hz in- duction motor runs at a slip of 0.025 at full load. Rotational and stray-load losses at full load are 5% of the output power. Calcul

Explain the hysteresis loop of a magnetic material, Explain the hysteresis ...

Explain the hysteresis loop of a magnetic material. Hystereses loop-Below the Curie temperature all-ferromagnetic materials show the identified hysteresis in the B (i.e. flux

Electronics, Let me know if you can help during the test

Let me know if you can help during the test

What is session layer, Q. What is Session Layer? Session layer is used ...

Q. What is Session Layer? Session layer is used to allow users to identify themselves when waiting access to the network. This is concerned with setting up and sustaining an op

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