The title may surprise new generation of Turbine Engineers because L. P. Turbine Bearings are mounted in separate pedestals since BHEL the indigenous supplier began manufacturing as per KWU (German) technology.
But if you look at 200/210 MW Steam Turbines manufactured by BHEL as per LMW (Russian) technology the bearing housing is just an extension of lower half of L. P. Turbine. Even the Generator front bearing is placed in L. P. Turbine casing.
Condensers are placed on springs which get compressed due to weight of water in hot well, Condenser Tubes and Water Boxes. This may bring the bearings down and there was a theory that it may affect the alignment between I. P./ L. P. Rotor and L. P./Generator Rotor. Although we did not check the rotor alignment by filling water in hot well (normal level plus additional water equivalent to water in tubes and water boxes) this was done at other power projects. When one such expert visited Obra where I was doing the erection of 200 MW Steam Turbines, I showed him that the alignment was getting affected even due to variation in ambient temperature by taking the alignment readings at 4 PM and 6 AM. This was happening because the L. P. Turbine Casing expands and contracts vertically from its foundation and the height of the bearing from foundation is considerable.
The pedestal mounted bearings have more rigidity and they are not affected by movement of L. P. Turbine Casings due to weight of water or thermal expansion.
Recently I was asked whether 4x600 MW Steam Turbines at Jharsuguda manufactured by Dongfang have bearings in separate pedestals or in the extended portion of L. P. Turbine. The answer is very simple the Steam Turbine at Jharsuguda is state of the art and the bearings are mounted in separate pedestals like BHEL KWU design.
But if you look at 200/210 MW Steam Turbines manufactured by BHEL as per LMW (Russian) technology the bearing housing is just an extension of lower half of L. P. Turbine. Even the Generator front bearing is placed in L. P. Turbine casing.
Condensers are placed on springs which get compressed due to weight of water in hot well, Condenser Tubes and Water Boxes. This may bring the bearings down and there was a theory that it may affect the alignment between I. P./ L. P. Rotor and L. P./Generator Rotor. Although we did not check the rotor alignment by filling water in hot well (normal level plus additional water equivalent to water in tubes and water boxes) this was done at other power projects. When one such expert visited Obra where I was doing the erection of 200 MW Steam Turbines, I showed him that the alignment was getting affected even due to variation in ambient temperature by taking the alignment readings at 4 PM and 6 AM. This was happening because the L. P. Turbine Casing expands and contracts vertically from its foundation and the height of the bearing from foundation is considerable.
The pedestal mounted bearings have more rigidity and they are not affected by movement of L. P. Turbine Casings due to weight of water or thermal expansion.
Recently I was asked whether 4x600 MW Steam Turbines at Jharsuguda manufactured by Dongfang have bearings in separate pedestals or in the extended portion of L. P. Turbine. The answer is very simple the Steam Turbine at Jharsuguda is state of the art and the bearings are mounted in separate pedestals like BHEL KWU design.
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