What is Differential Expansion in Steam Turbine?

we have 30 mw DAE (Double automatic extraction) steam turbine .

1. what is differential expansion. - This can be found by you if you do a web search.

2. in which direction the rotor and casing expands - Depends on the configuration

3. and when. - See #1 above

4. how the proximity sensor measures this value? - See #2 above

In your studying for the above answers, you can also learn about turbine extraction!

Great answers. i like it. Saves us from doing all home work.

1. Differential expansion is the relative expansion of rotor w.r.t casing. 2. Expansion direction will be in the opposite direction of thrust bearing. 3. For proximity sensor you have to ask instrumentation people. I know that proximity sensor senses if a an object intersects. I don't know very clear about that..

differential expansion

Regards JD.

differential expansion is relative expansion of rotor w.r.t casing.basically steam direct strike to rotor then move to turbine exhaust point.steam pressure and temperature decrease as a steam pass from turbine stage.so steam almost contact with rotor w.r.t casing.so rotor expansion is greater then casing.

mostly in steam turbine,rotor expansion towards generator side and turbine casing expansion to wards opposite generator side(front pedestal side/high pressure turbine).it,s expansion depend on change in temperature and pressure rates.mostly expansion in start up.