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

Construction and working of analog type storage oscilloscope, Q.   Describe...

Q.   Describe in detail the construction and working of analog type storage oscilloscope. Explain the principle of secondary emission. Analog Storage Oscilloscopes: Storage o

Types of classification and coding systems, Illustrate the types of classif...

Illustrate the types of classification and coding systems? Briefly explain Production Flow Analysis? Discuss the basic concept of Composite part and different kinds of cell desi

Power distribution, Power Distribution You will study about the legisl...

Power Distribution You will study about the legislative measures that have been taken by our government to address these challenges. In particular, we discuss the Energy Conse

Explain polyphase induction motor, Q. Explain polyphase induction motor? ...

Q. Explain polyphase induction motor? The polyphase induction motor operates with polyphase alternating current applied to the primary winding, usually located on the stator of

Determine the cross-sectional conducting area, Q MCM is the abbreviation fo...

Q MCM is the abbreviation for 1 kcmil. problem for a de?nition of cmil.) Data for commercial-base aluminum electrical conductors list a 60-Hz resistance of 0.0880 /km at 75°C for

Determine potential drop between the terminals of a battery, The potential ...

The potential drop between the terminals of a battery is equal to the battery's EMF when: a) No current is drawn from the battery b) A very large current is drawn from th

Compare mosfet with jeft, Compare MOSFET with JEFT ? a. In enhancement ...

Compare MOSFET with JEFT ? a. In enhancement and depletion types of MOSFET, the transverse electric field induced across an insulating layer deposited on the semiconductor mate

Shunt dc motor, Shunt DC motor In this arrangement, the armature and f...

Shunt DC motor In this arrangement, the armature and field coils are connected in parallel (the motor is called 'shunt connected').     Analysis With refere

Distribution transformers, Distribution Transformers 1. Augmentation/...

Distribution Transformers 1. Augmentation/Addition of Distribution Transformers Distribution transformers have to be augmented by installing additional transformers or in

Antinoise systems — noise cancellation, Q. Antinoise Systems — Noise Cancel...

Q. Antinoise Systems — Noise Cancellation? Traditionally sound-absorbing materials have been used quite effectively to reduce noise levels in aircraft, amphitheaters, and other

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