# Synchronous generator droop, and motor speed regulation



## akyip (Aug 23, 2020)

Hey guys,

I just want to ask a clarification about synchronous generator droop and motor speed regulation.

Now, as I've always understood it, speed regulation is:

S.R. = (nNL - nFL) / nFL

For synchronous generator droop, according to the textbooks and Spin-Up PE Practice Exam:

Droop = (nNL - nFL) / nNL

However, I see in a reference handbook that:

Droop = (nNL - nFL) / nFL

Which is the correct formula for synchronous generator droop?

Thanks!


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## akyip (Aug 24, 2020)

Hey all,

I just noticed that I accidentally posted this topic 3 times by accident. On my screen, when I was trying to post this, an error message kept on popping up. Sorry for the triple post!


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## Orchid PE (Aug 24, 2020)

:banhim:


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## LyceeFruit PE (Aug 24, 2020)

akyip said:


> Hey all,
> 
> I just noticed that I accidentally posted this topic 3 times by accident. On my screen, when I was trying to post this, an error message kept on popping up. Sorry for the triple post!


you can report the other posts to the mods and have them delete them


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## akyip (Aug 24, 2020)

Alright, I will.

But is anyone able to answer my question about the correct formula for generator droop?

I always thought it was no-load speed (or frequency) on the denominator based on the Spin Up Exams and one of my textbooks about power system stability...

But I have another reference handbook that uses full-load speed on the denominator...

It should be no-load speed on the denominator for generator droop specifically, right?


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## Dothracki PE (Aug 24, 2020)

Chattaneer PE said:


> :banhim:


That would be this thread...


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## Dothracki PE (Aug 24, 2020)

akyip said:


> Hey guys,
> 
> I just want to ask a clarification about synchronous generator droop and motor speed regulation.
> 
> ...


I am seeing speed regulation formula following the same formula as voltage regulation with the synchronous speed at full load in the denominator. I confirmed with Graffeo's book and an online reference sheet I had printed out a while back. Just to confirm droop is another term for speed regulation? I don't typically deal with that level of motors/generators at work.


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## Dothracki PE (Aug 24, 2020)

TRIPLE POST


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## Orchid PE (Aug 24, 2020)

*probably wrong*


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## akyip (Aug 24, 2020)

Chattaneer PE said:


> View attachment 18485


Thank you, Chattaneer. It definitely looks like there's a difference between motor speed regulation and generator droop.


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## Orchid PE (Aug 24, 2020)

akyip said:


> Thank you, Chattaneer. It definitely looks like there's a difference between motor speed regulation and generator droop.


Hold up. Checked my generator book and found


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