rotation speed 1

[facetoface]

We have got gas turbine model GT10B-Alstom and this turbine is double shaft (HP turbine and low pressure turbine)the HP turbine speed is variable and power turbine speed is constant as 77300 and reduucedto 1500 rpm to generator speed
The generator shaft is drived from both side steam turbine side and GT side through SSS clutch, when GT is stopped and ST is runnibg there are small speed 89 rpm at power turbine of GT where SSS clutch disengaged from GT side
Please, from where speed comming and is this problem and if yes how can solve

 

[turboco1]

The sliding component has internal helical splines. The teeth of a helical gear are inclined at an angle to the axis of rotation of the gear. Helical gears are smoother running than spur gears and are more suitable for rotation at high velocities. The acrobat file on the SSSclutches website has a cross sectional view showing the sliding component and internal helical splines.

see:

http://www.ul.ie/~nolk/gears.htm#Gear types

scroll about 25% down from Top of fully loaded page: Single and Double Helical Gears

I copied the link to Grupo Mio, use after you log in.

http://www.friendster.com/group/tabmain.php?statpos=mygroup&gid=65632

 

[abeltio]

phe

http://wwww,

this is a very long thread...
sakram's problem is a well known problem when using SSS clutches and the GT is shutdown.
some GT OEM's (like GE) installed brakes (solenoid actuated) to stop the GT shaft from turning by viscous drag created by the SSS.
The whole shaftline should be fed by the same lube oil system (single shaft combined cycle configuration) in case the there is a loss of L.O. pressure - the low lube oil pressure trip will protect all the units.

i have seen this before and there is no problem... except that there is a nuisance to see GT rotation when there should be none.

the only problem is if there is a need to restart the turbine and the unit does not have flying re-start capability... i.e. a start signal needs a zero speed detection in order to be accepted.

aeroderivative units usually use a hydraulic cranking system so flying restart should not be an issue.

SSS is a very helpful crowd... they will surely be able to suply info regarding this issue and offer solutions.
Also, the GT OEM should be able to assist to implement the brake solution.
In industrial type units (wrongly called heavy duty) the inertia of the shaft is enough to keep the shaft at zero speed once the brakes are released. May be in aeroderivative units you will need to apply the brakes permanently... the power turbine turns so smoothly that you can actually turn it by hand (i've done it).

HTH.


saludos.
a.

 

[facetoface]

Dear turbo1.,now at engage:Ratch teeth connect with Pawl and in disengag:ratchet teeth is not contact wih pawl