CR4® - The Engineer's Place for News and Discussion®

 Previous in Forum: Driveshaft Guard Next in Forum: High Gland Sealing Pressure
Associate

Join Date: Jul 2011
Posts: 42

# Can Someone Please Define Stem Turbine Idle Speed, Rated Speed and Minimum Governing Speed?

05/09/2013 11:44 PM

How do you define the Idle speed, rated speed, critical speed bands and Minimum governing speed of a HP Steam turbine driven compressor?

Interested in this topic? By joining CR4 you can "subscribe" to

Guru

Join Date: Oct 2008
Posts: 40534
#1

### Re: Can someone please define Idle Speed, Rated Speed and Minimum Governing Speed?

05/09/2013 11:59 PM

I don't. I search for a definition on the web. Something like this.

Steam turbine - Wikipedia, the free encyclopedia

Electric generator - Wikipedia, the free encyclopedia

There are many more there, if you don't like that one.

Guru

Join Date: Sep 2007
Location: Japan
Posts: 2716
#2

### Re: Can someone please define Idle Speed, Rated Speed and Minimum Governing Speed?

05/10/2013 12:13 AM
__________________
From the Movie "The Big Lebowski" Don't pee on the carpet man!
2
Associate

Join Date: Apr 2011
Posts: 45
#3

### Re: Can Someone Please Define Stem Turbine Idle Speed, Rated Speed and Minimum Governing Speed?

05/10/2013 11:21 PM

I know that most steam turbines run at 3600 rpms and at no load the generator is not tied on line. It still maintains 3600 rpms due to the frequency of the load once it is tied to the grid. The critical speed of a turbine is the speed that it goes into an unbalanced mode. You are asking about a steam turbine that drives a compressor. The idle spped would be the lowest speed that they run the turbine to turn the compressor. The rated speed is the maximum speed that you can run the compressor without doing damage to it. You will have to check the manual for that turbine-compressor setup and to find out the actual running speeds. The 1st critical speed is going to be some where between 1800 to 2500 rpm's. The 2nd critical is somewhere above 3600 rpm's. The OEM company that makes the turbine can give you this info. Hope this helps answer your question.

Guru

Join Date: Jan 2008
Posts: 1756
#4

### Re: Can Someone Please Define Stem Turbine Idle Speed, Rated Speed and Minimum Governing Speed?

05/14/2013 2:08 PM

I do not define any of those speeds, nor anybody else.

The manufacturer specifies them. The manfacturer alone is in the position to do so.

In particular, critical bands to be avoided (more exactly passed thru fast only) is specified for a particular turbine and load combination.

You may ignore that, and end up with a turbine in small pieces and a damaged generator.

Interested in this topic? By joining CR4 you can "subscribe" to