Power Plant Alternator

The answers to your questions would be rather lengthy. I suggest you use your internet search engine with the key words "excitation" or "synchronous machine".

Hi Sparky,

I think your answer is very deep.

Simpler would be:-Exitation is the current passing through the rotor coils that make the rotating magnetic field needed for the output windings to produce power.

I am a little surprised by your answer in that you state that large machines use sliprings and commutators. Even on more modest machines from say 10kVA to 100kVA all field coupling is done via field stator and field rotor with rotating diodes. Is the example provided very old?

regards

chas

Hello capblanc (chas)

Thank you for your comments.

Many years ago, I found that instead of just answering a question, if additional explanatory information was given, often with a picture or two, the understanding level of the question asker was increased, along with them becoming interested further in the subject.

Of course the simpler answer as you give: <"....Exitation is the current passing through the rotor coils that make the rotating magnetic field needed for the output windings to produce power.....">

But without any reference to some physical thing, the concept as explained by the above simpler answer is a "stone wall" ending, without encouragement to learn more.

The next questions asked by the question asker, if they are wanting to learn are:

1. What is current?
2. What are rotor coils?
3. what is a rotating magnetic field?
4. What are output windings?
5. What is power?

The problem with learning, is that to learn successfully, each person must first "learn how to learn", or a jumble of facts is assimilated, which facts may be regurgitated in an exam or test, in the manner of a parrot, without proper understanding, but no real learning has occurred.

So: To learn how to learn, first the learner needs to have widespread experiences, some basic "tree" to hang further details onto - The "Filing Cabinet" of the mind has to be filled with file holders, ready to name and be placed in proper order, all with cross-references, so the information may be recalled.

Example: What is casting during fishing?

A very short answer may be given: Tossing a baited or lured line into the water, repeatedly.

Or a much more complete answer may be given, referring to different types of streams/rivers, famous anglers, the book "The Compleat Angler" by Izaak Walton, species of fish, lures, baits, rods, waders, creels, gaffs, and more, along with a relevant picture or two, especially if animated, such as at the left here.

I would ask you to think: Which answer would help you to remember more about the subject of the question: What is casting during fishing?

Which answer would encourage you to learn more about the subject of the question: What is casting during fishing?

Please be honest with yourself, when you answer those two above questions.

Life here on Earth is a very short span, a mere flicker when compared with the lack of time, which is eternity.

One of the reasons we all are here, whether we like it or not, is to help each other, and I try to do that to the best of my ability, in assisting others.

Yes, often I give extra information, and as explained above, the extra information is to "whet the appetite" of the reader, so they may search for more, understand properly, and be able to share that understanding with others.

I discovered years ago, there are two types of knowledge sharers:

1. Preachers
2. Teachers

1. A Preacher just spouts it off, like a parrot, not really caring whether the person trying to learn has properly understood. The reason generally is because the Preacher was taught by Preachers.

2. A Teacher gets alongside the person, asks: "What do you know about this?" or if a question is asked, the Teacher is able, from the context of the question, establish the level of knowledge of the enquirer or student. The Teacher then builds on the existing knowledge base of the student/enquirer, giving extra information to encourage further learning, as I've written above.

Referring to your second comment: Evidently you did not refer to the hyperlink given, http://www.doe.carleton.ca/~jknight/Power/ChatsFalls/PowerStation_1.html (perhaps your knowledge base could be increased if you had) as in the hyperlink given you would have read:The plant is jointly owned by the Ontario Power Generation, who owns units 2, 3, 4, 5 (24 MW each) and Hydro Quebec, who owns units 6, 7, 8, 9). These generators were installed in 1931/32.

Now I do appreciate that in many modern alternators, <"....field coupling is done via field stator and field rotor with rotating diodes...."> but those early alternators were made long before semiconductor diodes had been invented, and those same alternators are still working well, after nearly 80 years of service.

For you to bring in the <"....field coupling is done via field stator and field rotor with rotating diodes...."> shows that your interest in the subject was whetted, and I'm pleased about that. (I think your answer is very deep)

Large machines are still being made with the slipring/brush method, because these are inherently more reliable, easy to inspect/test/repair/replace.

As always, if you need to, reply here, with

Kind Regards....