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

Design an electro-pneumatic system, (i) Sketch a fully-labelled electro-pne...

(i) Sketch a fully-labelled electro-pneumatic circuit showing your actuators in the START position and employ metered out speed control with mono-stable 5/2 DCV's having solenoid a

Define asynchronous communication with serial communication, With respect t...

With respect to serial communication define the asynchronous communication. Asynchronous implies "no synchronization", and therefore does not require sending and receiving idl

Power diode - power semiconductor devices , Power Diode A power diode i...

Power Diode A power diode is a two terminal, anode a and cathode K and  two layer P  and  N  junction devices. A PN  junction normally  formed  by allowing  diffusion and epita

Describe the working of bistable multivibrator, Q. Describe the working of ...

Q. Describe the working of bistable multivibrator A bistable circuit is one which can exit indefinitely  in either of two stable states and which can be induced to make an abru

Smallest unit of information on a machine, Q. Smallest unit of information ...

Q. Smallest unit of information on a machine? Short for the binary digit the smallest unit of information on a machine. This term was first used in 1946 by the John Tukey, a le

Sources of power dissipation in cmos logic, Describe the three main sources...

Describe the three main sources of power dissipation in CMOS logic. Hence calculate the power dissipated in a CMOS ASIC of 40,000 gates operating at a frequency of 133MHz with a s

Compute the smallest load resistance, Q. A practical voltage source is repr...

Q. A practical voltage source is represented by an ideal voltage source of 30 V along with a series internal source resistance of 1.2 . Compute the smallest load resistance that c

Responsibilities of Regulatory Body, Responsibilities of Regulatory Body ...

Responsibilities of Regulatory Body The basic responsibilities of the Central Regulatory Commission are to: Fix tariff of Central Sector producing plants as well as of

Describe the process control instructions, Describe the process control ins...

Describe the process control instructions STC - It sets the carry flag & does not affect any other flag  CLC - it resets the carry flag to zero &does not affect any other fl

How you can convert a galvanometer to a voltmeter, To convert a galvanomete...

To convert a galvanometer to a voltmeter, you should add a: a) High resistance in series b) High resistance in parallel c) Low resistance in series d) Low resis

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