excitation

jacquis delumen

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• Jul 9, 2006

• #1

why does the power factor of underexcited synchronous generator becomes leading..?

 

SimonGoldsworthy

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• Jul 10, 2006

• #2

What is the generator connected to ?

 

rdrast

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• Jul 10, 2006

• #3

All you ever wanted to know about synchronous motors, and then some...
http://www.kilowattclassroom.com/Archive/SyncMotors.pdf

 

BobB

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• Jul 10, 2006

• #4

What a great link! Have not played with these things since I was an apprentice - a decade or five ago.

Generally, synchronous motors are used for synchronous speed and to improve power factor. I have never really heard of a "synchronous" generator. All generators are driven at synchronous speed by the engine.

Is this a "trick" student question?

 

randylud

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• Jul 11, 2006

• #5

Bob, the term synchronous generator is probably a misnomer. It is used here in the US, and seemingly other places, to describe the use of a 3 phase induction motor as a generator driven by some prime mover. The practice is often used for peak shaving but the characteristics of the induction motor do not make it capacitive as I understand it. DickDV will doubtless have more precise info on this subject.

 

randylud

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• Jul 11, 2006

• #6

Doing a little research on the subject of leading power factor and motors, I find that you can use a synchronous motor in that fashion by over-excitation of the rotor. This may be what the original question was really about.

 

rdrast

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• Jul 11, 2006

• #7

randylud said:

Doing a little research on the subject of leading power factor and motors, I find that you can use a synchronous motor in that fashion by over-excitation of the rotor. This may be what the original question was really about.

Click to expand...

/nod. I got heavily into large synchronous motors at one site that had a 2500HP one, virtually never used, and the electrical supervisor heard about using them to correct power factor.
At the time, they were running a pretty bad lagging PF, and were considering an expensive switched capacitor set. In the end, we brought it to near unity with just the motor.