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Is it true that as long as sleeping frequency increases, the torque on the rotor shaft increases too? I ask you because I have read this in a book (John E.Traister, "Handbook of Power Generation", Prentice-Hall publication, Reading, 1983) but my coordinator professor doesn't agree with that affirmation.

I will quote the exact paragraph: "As sleeping frequency increases, torque on the rotor shaft increases. That could result into severe damage of generator."

Thank you, with very best regards,
Marius Jantea

Marius Jantea,

I am unfamiliar with the term "sleeping frequency". I have looked through all my reference and text books, including a copy of "Power Generation Handbook" and can find nothing about "sleeping frequency".

Can you provide some context? What is the title of the chapter you find the first reference to this term? Is there a subtitle to the section in the chapter? Is the author attempting to discuss droop speed control?

> Is it true that as long as sleeping frequency increases, the torque on the rotor shaft increases too? I ask you
> because I have read this in a book (John E.Traister, "Handbook of Power Generation", Prentice-Hall publication,
> Reading, 1983) but my coordinator professor doesn't agree with that affirmation.
---- snip ----

Did you mean slipping frequency? It makes more sense I think.

Like Namatimangan08, I too believe it is a misprint, ant the correct term is "slip-fequency!"

Phil Corso

Phil Corso/Namantingan08,

Presuming it's "slipping frequency" or "slip frequency", can you answer the original poster's question of what happens when the slip- or slipping frequency of a generator increases?

CSA... only if Marius is actually referring to "slipping" a pole!

Regards, Phil

Marius... Namantingan08 & ProcessValue, both presented some information on pole-slipping, I suggest you start with:

http://www.control.com/thread/1267218529

Regards, Phil

> Marius... Namantingan08 & ProcessValue, both presented some information on pole-slipping,

Maybe the poster meant slip frequency, eventually turned out to become slip pole.

There are two possible corrections that I can make. 1. As long as slip frequency increases generator torque angle will increase.... 2. As long as slip frequency increase generator torque will increase.....

I think we have to wait for the poster to make clarification.

Marius... slip-frequency only "changes" if the machine has lost excitation and it then operates as an induction-generator! In fact its speed increases with respect to grid-frequency. Shaft-torque also increases!

For the case where it has commenced slipping its first pole, then the increasing torque-angle (with respect to the grid-reference) accounts for an increase shaft-torque, until the electro-magnetic force is insufficient to maintain synchronism between stator and rotor!

Regards, Phil Corso

> Is it true that as long as sleeping frequency increases, the torque on the rotor shaft increases too? I ask you
> because I have read this in a book (John E.Traister, "Handbook of Power Generation", Prentice-Hall publication,
> Reading, 1983) but my coordinator professor doesn't agree with that affirmation.

> I will quote the exact paragraph: "As sleeping frequency increases, torque on the rotor shaft increases. That could
> result into severe damage of generator."

Probably you have to rephrase your statement as the following:

"As slip frequency increases, accelerating torque on the rotor shaft increases. That could result into severe damage of generator."

Under steady state condition, rotor accelerating torque is zero or very close to it. The torque produces by stator will be balanced up by opposing torque from electrical loads.

The sentences Marius quoted from a textbook actually appear in a paper that was submitted in partial requirements of a Master's degree (!) in 2009.

The paper is titled "INTEGRATED EQUIPMENT OPERATION AND CENTRAL CONTROL SYSTEM OF POWER PLANTS" by Maunank V Patel and Nilay K Desai at California State University in Sacramento. The authors also list John Traister's book as a reference.

Here is a link to the paper, copied from a Google Search result for ["sleeping frequency" electric generator]:

http://www.google.ca/url?sa=t&rct=j&q=%22sleeping%20frequen cy%22%20%20electric%20generator&source=web&cd=6&ved=0CFwQFjAF &url=http%3A%2F%2Fcsus-dspace.calstate.edu%2Fxmlui%2Fbitstream%2Fhand le%2F10211.9%2F241%2FMS_Project%2520Report_Nilay_Maunank_3.0.doc%3Fsequen ce%3D2&ei=F3L0T6bmDoKgrAH3ppjSAw&usg=AFQjCNEUkpjsspISYd-kwwnJqY3p Ii9u9Q

I know this isn't an academic forum but something seems wrong here. People's time is also being wasted chasing a nonsense term.

> The sentences Marius quoted from a textbook actually appear in a paper that
> was submitted in partial requirements of a Master's degree (!) in 2009.

---- snip ----

> I know this isn't an academic forum but something seems wrong here. People's
> time is also being wasted chasing a nonsense term.

Tq. I have gone through that part. So that sleeping frequency shall be read "slipping frequency" or slip frequency.

Maybe this term is the main concern to the poster's professor. Then, I think I'm done.