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

Charge carriers in semiconductors, Charge Carriers in Semiconductors ...

Charge Carriers in Semiconductors In a metal, the atoms are imbedded in a "sea" of free electrons, and these electrons can move as a group under the influence of an

Ujt as a relaxation oscillator , UJT as a  relaxation  oscillator Th...

UJT as a  relaxation  oscillator The UJT  is a highly  efficient  switch  it is  used as trigger  a device for SCR. No sinusoidal oscillators saw tooth generators phase contro

Why negative feedback is employed in wein bridge oscillator, Q. Why negativ...

Q. Why negative feedback is employed in Wein Bridge Oscillator. Also explain the working of oscillator? The Wein Bridge Oscillator consists of two stages of the RC coupled ampl

Write a short note on the working of darlington amplifier, Q. Write a sho...

Q. Write a short note on the working of Darlington Amplifier? A Darlington Amplifier is one that is employing the Darlington pair of transistors. It is a

Explain dielectric current, Dielectric: Insulator that is used among th...

Dielectric: Insulator that is used among the two plates of a capacitance is called as dielectric.  Electric field exists in the dielectric and the flux density depends on th

Determine the magnitude of the current, Determine the magnitude of the curr...

Determine the magnitude of the current: For the circuit of Figure below determine the magnitude of the voltage "drops" across each resistor R1 - R7. Determine the magnitude

Show principal source of energy, Q. Show Principal source of energy? Th...

Q. Show Principal source of energy? The principal source of energy comes from the burning of fossil fuels such as coal and oil to generate steam, which drives steam turbines, w

#title.ec 1., draw the gain frequency response of an RC coupled circuit? di...

draw the gain frequency response of an RC coupled circuit? discuss fall in gain at very low and very high frequencies?

Calculate the length of the wire required to get resistance, An  electric  ...

An  electric  heater  element  is  made  of  Nichrome  wire  having  resistivity  equal  to 100 ×10 -8 ohm-metre. The diameter of the wire is 0.3 mm. Calculate the length of the w

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