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

Ac motors, If the stator windings of an alternator were to be supplied ...

If the stator windings of an alternator were to be supplied by an AC of frequency f (as opposed to drawing an AC current from them as would be the case for an alternator) then

Effect of feedback on stability, Q. Effect of feedback on stability? Le...

Q. Effect of feedback on stability? Let us consider the direct transfer function of the unstable first-order system of Figure (a). The transfer function is given by whe

Explain sar instructions in 8086 family, Explain SAR instructions in 8086...

Explain SAR instructions in 8086 family with example and their effect on flag. SAR: Shift each bit of operand right through given number of bits, this instruction shifts eve

What do you mean by assembly procedures in fem, a) What do you mean by asse...

a) What do you mean by assembly procedures in FEM, discuss by taking suitable example of your choice. b) Write the potential energy equation for particular FE analysis of a prob

What are operations performed on data in 8085, What are operations performe...

What are operations performed on data in 8085 The various operations performed are Store 8-bit data Perform arithmetic and logical operations Test for conditio

Sketch a graph comparing the fcc class, a) In the United States, the Federa...

a) In the United States, the Federal Communications Commission (FCC) is charged with the regulation of radio and wire communication (FCC part 15). It basically sets limits on the

What are difference equations, What are Difference Equations? A continu...

What are Difference Equations? A continuous-time system can be described by differential equations. Likewise, a discrete-time system can be explained by difference equations. T

Sketch voltage and the energy stored in the capacitor, Q. Considering the c...

Q. Considering the circuit shown in Figure, sketch v(t) and the energy stored in the capacitor as a function of time.

Analog circuit, What is the disadvantages of diodes as a series element in ...

What is the disadvantages of diodes as a series element in a clipper?

Transparent latch d flip flop, Transparent latch D flip  Flop A typica...

Transparent latch D flip  Flop A typical  example  of this  type of D flop  is 7475 shown  in figure when CLK  connected is enable signal is high and the flip  flop  is enabled

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