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8 comments
Participant

Join Date: Jan 2011
Posts: 3

Why Are There No Jacking Oil Pumps in Some Turbines in Some Powerplants?

01/02/2011 8:10 AM

Hi everyone ,,, Hope that I find the answer here with your help !!

I am a fresh engineer, I still under training,,

My question is why there is no jacking oil pumps in some turbines in some power plants ? Is it because of the bearing types used to lift the turbine shaft or not ?? If yes, what are these types ?

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Guru
Engineering Fields - Electrical Engineering - New Member United Kingdom - Member - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2010
Location: Under the Major Oak
Posts: 3426
Good Answers: 137
#1

Re: Why There is No Jacking Oil Pumps in Some Turbines in Some Powerplants?

01/02/2011 10:13 AM

Part of your training involves learning how to gain information. Try reading your text books.

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Participant

Join Date: Jan 2011
Posts: 3
#2
In reply to #1

Re: Why There is No Jacking Oil Pumps in Some Turbines in Some Powerplants?

01/02/2011 11:31 AM

I tried but I coudlent find it !! I you have a handbook tell me its name !!

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Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Ketchikan, AK, USA
Posts: 14976
Good Answers: 564
#3

Re: Why There is No Jacking Oil Pumps in Some Turbines in Some Powerplants?

01/02/2011 1:03 PM

Sleeve bearings would likely need jacking pumps; other types of bearings might not. A general textbook might not cover this, but the manuals for your specific types of turbines could have this information. If any manuals have been lost, try contacting the manufacturer.

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Participant

Join Date: Jan 2011
Posts: 3
#4
In reply to #3

Re: Why There is No Jacking Oil Pumps in Some Turbines in Some Powerplants?

01/02/2011 3:30 PM

thank you Tornado

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Anonymous Poster
#5

Re: Why There is No Jacking Oil Pumps in Some Turbines in Some Powerplants?

01/02/2011 6:18 PM

Jacking oil or as its commonly called "lift oil" is a common feature on some gas and steam turbines. The reason for jacking oil is to allow the rotor to be lifting by a stream of high pressure oil when the unit is first rotated thus greatly reducing the amount of breakaway torque necessary. Many units with shorter spans between bearings and larger turning gears (that can supply a higher torque) do not have lift oil.

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Anonymous Poster
#6

Re: Why Are There No Jacking Oil Pumps in Some Turbines in Some Powerplants?

01/03/2011 8:56 AM

Steam Turbines, normally, have Carbon-Carbon bearings/packing glands that are lubricated by HP steam.

The "jacking pumps" are, normally, used for the PTO equipments that are not steam lubricated. Steam Turbines operate at very high RPM, which is reduced to a usable velocity.

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Anonymous Poster
#7

Re: Why Are There No Jacking Oil Pumps in Some Turbines in Some Powerplants?

01/03/2011 9:38 AM

Another use of lifting oil (or jacking oil) is to prevent damage to the turbine bearings when the unit is offline. The shaft of the turbine is 1000 F (+/-). Setting a shaft of this temperature directly on a babbit bearing will destroy the babbit. Keeping the lift oil system on when the turbine is at a low RPM will keep an oil wedge between the shaft and bearings.

Oh, and TonyS, this type of information is not contained in most text books. You must usually go to turbine manuals to find it, and each manual is different based on the requirements of each particular machine. And this young engineer is learning how to gain information, by asking other, more knowledgeable and experienced engineers (ie: interacting with peers). This is the first response of yours that I've read; but if this is the extent of most of your responses I can see why only 26 out of 868 have been marked as good.

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Commentator

Join Date: Sep 2006
Posts: 57
#8

Re: Why Are There No Jacking Oil Pumps in Some Turbines in Some Powerplants?

01/03/2011 10:29 AM

Hello everybody:

In hydroelectric power plants, where turbines with vertical shaft are installed, the generator has a "generator oil lifting pump", which operates at the starting and the stopping of the unit, in order to lift the generator and build up an oil layer between the thrust bearing pads and the thrust collar on the generator shaft.

With such an action, it is avoided any damage of the Babbitt metal (or whatever be the white metal bearing alloy) of the bearing pads.

In one word: to create an oil film to avoid the start and the stop of the unit in a "dry condition".

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Users who posted comments:

ahmed4900 (2); Anonymous Poster (3); ELEMAN (1); TonyS (1); Tornado (1)

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