COUPLING

 

GENERAL INFORMATION:

The basic functions of the flexible gear type couplings used on this turbine are to:

a. connect two rotating shafts in order to transmit torque from one to the other,

b. compensate for all three types of misalignment (parallel, angular and a combination of

both),

c. compensate for any axial movement of the shafts so that neither exerts an excessive

thrust on the other.

Parallel misalignment is when the two connected shafts are parallel, but not on the same

straight line. Angular misalignment occurs when two shafts are on the same straight line but

their center lines are not parallel. Combined misalignment occurs when the shafts are neither

parallel nor on the same straight line. Axial movement is when one or both shafts are displaced

along their axis (center line).

Two couplings are used on this turbine:

a. one connects the accessory drive gear with the turbine

shaft, and

b. the other connects the turbine shaft with the load equipment.

For specific and detailed information relevant to coupling refer to sub-supplier manual

enclosed in Auxiliary Equipment And Instrumentation volume 4 of this manual.

CONTINUOUSLY-LUBRICATED ACCESSORY GEAR COUPLING:

The coupling is a continuously-lubricated flexible gear-type device. It uses a hub of male teeth

fitted at each end of a distance piece. The male teeth mesh with the female teeth of a sleeve at

each end, to transmit the torque. The male teeth are crowned and can slide fore and aft within

the female spline.

This allows for all three types of misalignment.

The sleeve at the accessory gear end is bolted to a flange (hub) which has been shrink-fitted and keyed to the accessory gear shaft. The sleeve at the turbine end is bolted directly to the turbine rotor.

LOAD COUPLING:

The non-lubricated coupling consists of flexible diaphragms, adapter shafts and a centre shaft.

The adapter shaft, fitted to the ends of the centre shaft, includes flanges which interface with

the load compressor and the load turbine rotor shaft and also provide support for the flexible

diaphragms. The diaphragm sections provide the flexibility to compensate for the nominal

misalignment between the load equipment and the load turbine rotor, and permit axial

movement of the turbine relative to the load equipment.