Elevator Mechanic Practice Exam

What type of oil is required for sleeve bearings?

1. Double viscosity SAE 30

2. Single viscosity SAE 10

3. Single viscosity SAE 20

4. Variable viscosity SAE 20

The correct answer is: Double viscosity SAE 30

The correct choice is based on the recommended specifications for lubrication of sleeve bearings in elevator systems. Sleeve bearings typically require a specific type of oil to ensure optimal performance, reducing friction and wear during operation. Double viscosity SAE 30 oil is designed to maintain a stable viscosity across a range of temperatures, providing effective lubrication under varying operating conditions. This characteristic is essential for sleeve bearings as they may experience changes in temperature and load. The double viscosity aspect also contributes to better performance, especially in environments where bearings might be subject to higher temperatures or heavier loads. The other choices, while they may have their own applications, do not meet the specific lubrication requirements for sleeve bearings in the same way Double viscosity SAE 30 does. For example, single viscosity oils lack the same temperature stability, which could lead to inadequate lubrication and increased wear or failure of the bearing under fluctuating conditions. Variable viscosity oils, on the other hand, might not provide the level of protection necessary for consistent operation, especially in stationary applications where reliable performance is crucial.