As the plant condition monitoring engineer, you have been instructed to improve the lubrication practices for your plant’s turbine alternator by first understanding the current situation practices and then establishing a lubrication monitoring program for ongoing management.
The lubrication system
The system provides 64 kilolitres of lubrication oil to the steam turbine that drives a 300-mega watt generator.
Notes on the system:
• For the past 20 years the oil has been replaced on an annual basis. When asked why this was done you were told that was how it had always been.
• Known problems within the existing lubrication system include, water ingress, minor leaks at sump joins and hose connections. After each lubrication change, major control system malfunctions occur. (Control system manufacturer’s tolerances include internal clearances of 3 micrometres.)
• An older style centrifuge unit is used to remove the water but with minimal success.
• Top up is unmonitored and carried out by untrained personnel.
• There are no breathers within the system and the system is open to the atmosphere.
• Due to the nature of the building, oil changes are carried out by syphoning 205 litre drums into a storage tank, which then feeds the turbine sump.
• Some chemical analysis of the lubrication is carried out, but the results are filed and not used.
• After checking these typical chemical results you find that the chemical properties of the lubricant have been satisfactory at the time of sampling.
• An initial cleanliness check was carried out, and this showed that the new oil arrived at the sump dirtier than that in service.
• Generally there was no perceived ownership for the turbine’s lubrication system.
The lubrication system
The system provides 64 kilolitres of lubrication oil to the steam turbine that drives a 300-mega watt generator.
Notes on the system:
• For the past 20 years the oil has been replaced on an annual basis. When asked why this was done you were told that was how it had always been.
• Known problems within the existing lubrication system include, water ingress, minor leaks at sump joins and hose connections. After each lubrication change, major control system malfunctions occur. (Control system manufacturer’s tolerances include internal clearances of 3 micrometres.)
• An older style centrifuge unit is used to remove the water but with minimal success.
• Top up is unmonitored and carried out by untrained personnel.
• There are no breathers within the system and the system is open to the atmosphere.
• Due to the nature of the building, oil changes are carried out by syphoning 205 litre drums into a storage tank, which then feeds the turbine sump.
• Some chemical analysis of the lubrication is carried out, but the results are filed and not used.
• After checking these typical chemical results you find that the chemical properties of the lubricant have been satisfactory at the time of sampling.
• An initial cleanliness check was carried out, and this showed that the new oil arrived at the sump dirtier than that in service.
• Generally there was no perceived ownership for the turbine’s lubrication system.
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