Oilers/Plant Tenders (HHC) Civil Service Practice Exam

By how many degrees Fahrenheit is the oil at the bearing surface of a steam turbine usually hotter than the bearing oil discharge temperature?

1. 10 to 30 degrees F

2. 30 to 50 degrees F

3. 50 to 80 degrees F

4. 80 to 100 degrees F

The correct answer is: 50 to 80 degrees F

The oil at the bearing surface of a steam turbine is typically hotter than the bearing oil discharge temperature due to the heat generated from the friction between the moving parts and the transfer of thermal energy during operation. In steam turbines, the design considerations account for lubrication efficiency and the ability to dissipate heat. The correct range indicates that, under normal operating conditions, the temperature difference can indeed be expected to fall between 50 to 80 degrees Fahrenheit. This temperature differential is crucial for ensuring adequate lubrication and preventing overheating, which can lead to equipment failure. Understanding this temperature relationship is important for maintenance and operational efficiency. Monitoring the oil temperature at the bearing surface can help operators assess the thermal condition of the turbine and take necessary actions to maintain optimal performance. The other ranges provided do not accurately reflect typical operational conditions for steam turbines, which is why they are less appropriate choices.