Sites: GlobalSpec.com | GlobalSpec Electronics | CR4 | Electronics360
Login | Register
The Engineer's Place for News and Discussion®

Previous in Forum: Remote Current Monitoring   Next in Forum: Active and Reactive Load Sharing
Close

Comments Format:






Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







7 comments
Participant

Join Date: Aug 2009
Posts: 2

Exciter Function in Three-Phase AC Generator

08/05/2009 3:14 PM

I would like to know the function of exciter in 3-phase AC generator. As far that i know its gives the starting torque to the generator which helps in pre acceleration of the generator. Is there other function of exciter in the generator? A detail circuit diagram will help too. tq

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Power-User
Australia - Member - New Member Hobbies - Target Shooting - New Member Popular Science - Weaponology - New Member

Join Date: Dec 2007
Location: Sydney Australia
Posts: 479
Good Answers: 35
#1

Re: Exciter Function in Three-Phase AC Generator

08/05/2009 7:43 PM

The Exciter Function is to provide a Magnetic Field through which conductors may be rotated to generate a voltage and thus allow a current to flow.

Regards,
Sapper

__________________
It's all about the Boom! - MythBusters
Register to Reply
Guru

Join Date: Mar 2007
Posts: 2550
Good Answers: 105
#2

Re: Exciter Function in Three-Phase AC Generator

08/06/2009 1:44 AM

Do you mean Generator or Motor ?

Do you mean Exciter Circuit or starting means ?

If it is Exciter and generator then the previous post is correct. It creates and maintains the Magnetic field and its strength so that the necessary energy converson takes place.

If it is Starting of Synchr Motor (In induction mode) then what you said is OK.

__________________
Fantastic ideas for a Fantastic World, I make the illogical logical.They put me in cars,they put me in yer tv.They put me in stereos and those little radios you stick in your ears.They even put me in watches, they have teeny gremlins for your watches
Register to Reply
Guru
Australia - Member - New Member Engineering Fields - Mechanical Engineering - New Member

Join Date: Sep 2006
Location: NSW Australia
Posts: 1027
Good Answers: 22
#3

Re: Exciter Function in Three-Phase AC Generator

08/06/2009 9:08 AM

The function of an exciter in a 3 phase AC alternator is to provide power to the rotating field ,this field cuts the windings of the stator which produces your 3phase output. The output of this exciter can be varied manually or automatically depending on the alternator function.This type of exciter in the form of a DC generator can be mounted on the end of the alternator and is usually self exciting. This method can also be used on DC generators to feed the stator field coils. It douse not give any starting tourque to the alternater unless it is speacialy wound to act as a starter come generator.

Other types of exciters have their windings incorperated in the stator windings the output of these exciter windings are rectified and fead to the rotor, in this case the output of these windings are usualy regulated automaticaly so the alternator output is stabilised. Some of these types are self exciting others require a DC supply from a battery to start up the system

There are hundreds of variations so would suggest you google up any of the above for circuit information.

Garth

__________________
Dont get on to the roundabout if you dont know how to get off
Register to Reply Score 1 for Good Answer
Guru

Join Date: Feb 2009
Location: Houston, USA
Posts: 968
Good Answers: 242
#4
In reply to #3

Re: Exciter Function in Three-Phase AC Generator

08/06/2009 8:48 PM

Haq,

Are you asking for the initial excitation of generator?

The generator is first speeded up to its rated speed by the prime mover (Engine or Turbine), then it needs the initial excitation to build up the voltage. With initial excitation, an outside DC voltage pulse is directly applied to the exciter (Self-Brushless) field to generate the A.C voltage in its rotating armature. The AC voltage is converted to DC (with diode) which is then supplied to the generator rotating field to build up the voltage in the generator armature, which is the generator terminal voltage. Once the generator terminal voltage is built up, the exciter field current is controlled by the AVR.

The self-brushless exciter is a mini generator installed in the same rotating shaft – the basic difference is its field is stationary, its armature rotates and its frequency is higher.

This link may be of more help:

http://www.kilowattclassroom.com/Archive/SyncMotors.pdf

-MS

__________________
"All my technical advices in this forum must be consulted with and approved by a local registered professional engineer before implementation" - Mohammed Samad (Linkedin Profile: http://www.linkedin.com/in/msamad)
Register to Reply
Guru
Popular Science - Weaponology - New Member Safety - ESD - New Member Hobbies - Fishing - New Member

Join Date: Sep 2006
Location: Near Frankfurt am Main, Germany. 50.390866N, 8.884827E
Posts: 14178
Good Answers: 139
#6
In reply to #3

Re: Exciter Function in Three-Phase AC Generator

08/19/2009 10:48 AM

GA for the best answer up to now when reading down from the top.

__________________
"Better to remain silent and be thought a fool than to speak out and remove all doubt!"
Register to Reply
Commentator

Join Date: Jun 2008
Posts: 80
Good Answers: 5
#5

Re: Exciter Function in Three-Phase AC Generator

08/11/2009 11:57 AM

This sounds like homework and I think you should have gone to class that day. The "as far as I know" that you provided is so far off target I do not know where to start. What is "pre acceleration" anyway? Since when does a generator need "starting torque"? I do not think any circuit diagram, let alone one with detail will help you. Go read a book.

Register to Reply
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1190
Good Answers: 24
#7

Re: Exciter Function in Three-Phase AC Generator

08/25/2012 4:49 AM

Dear Mr. haq,

Starting Torque phenomena is applicable only for motor(s) - be it A.C or D.C Motor.

Exciter will circulate D.C current in the Rotating Field to provide Magnetic Flux, which will produce Voltage in the Windings of the stator. Pre-Acceleration does not arise in this matter.

DHAYANANDHAN.S

Register to Reply
Register to Reply 7 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Andy Germany (1); dhayanandhan (1); garth (1); Goodho (1); msamad (1); Sapper (1); sb (1)

Previous in Forum: Remote Current Monitoring   Next in Forum: Active and Reactive Load Sharing
You might be interested in: IC Waveform Synthesizers and Function Generators, Motor and Generator Winding Services, Comb Generators