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

Clipper, application and demerits

application and demerits

How phase angle measurement are carried out, Q.   Explain how phase angle m...

Q.   Explain how phase angle measurement are carried out with vector impedance meter.     Sol. Impedance measurements are concerned with both the magnitude (Z) and the phase

Explain the purpose of the i/o instructions in and out, Explain the purpose...

Explain the purpose of the I/O instructions IN and OUT. The IN instruction is used to move data from an I/O port into the accumulator. The OUT instruction is used to move d

Public safety - application of software defined radio, Public safety - Appl...

Public safety - Application of Software Defined Radio During emergency situation such as earthquake, tsunami, terrorist attack, public safety officials from different agencies

Explain the operation as a buffer, Q. An interesting application of the SRF...

Q. An interesting application of the SRFF is as a buffer in overcoming contact bounce in mechanical switches. These switches, of the toggle type, may be used to change the logic st

Digital Electronics, Design a MOD-6 synchronous counter using T Flip-Flops....

Design a MOD-6 synchronous counter using T Flip-Flops.

Evaluate a single-stage transistor amplifier, Design and using Pspice, eval...

Design and using Pspice, evaluate a single-stage transistor amplifier amplifier to meet the following specifications: * Power supply - 12V dc. · *Voltage gain - 120 when Vin

Compute efficiency of transformer in power factor lagging, Q. A 10-kVA, 200...

Q. A 10-kVA, 200:400-V, single-phase transformer gave these test results: • Open-circuit test (LVwinding supplied): 200V, 3.2 A, 450 W • Short-circuit test (HV winding suppli

What are the supplementary services, Q. What are the supplementary services...

Q. What are the supplementary services? new services are called supplementary services and some of the prominent ones are as below: Category 1: Abbreviateddialling

Single- and three-phase systems, Ac power has significant practical advanta...

Ac power has significant practical advantages over dc power in generation, transmission, and distribution. One major drawback of the single-phase circuit is the oscillatory nature

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