Oilers/Plant Tenders (HHC) Civil Service Practice Exam

What is the significance of oil viscosity when used for gear lubrication?

1. It is very important

2. Viscosity is not a concern

3. It should be as low as possible

4. It should be changed frequently

The correct answer is: It is very important

Oil viscosity plays a crucial role in gear lubrication as it directly impacts the effectiveness of lubrication under operating conditions. When viscosity is appropriately matched to the application's specific demands, it ensures that the oil can maintain a sufficient film strength between gear surfaces, preventing metal-to-metal contact, reducing wear, and enhancing the lifespan of the gear system. Higher viscosity oils can better support loads and maintain their properties under high-pressure conditions, which is common in gear assemblies. Conversely, low viscosity oils may not provide adequate protection, especially in high-load scenarios or at elevated temperatures where the oil could thin out. Therefore, having the right viscosity is very important to ensure optimal performance and reliability of the gears. In contrast, the other options do not adequately reflect the importance of viscosity. Stating that viscosity is not a concern entirely disregards its critical role in lubrication efficiency. Suggesting that it should be as low as possible ignores the balancing act of ensuring sufficient protection while allowing for good flow dynamics. Lastly, the idea that viscosity should be changed frequently may be relevant for maintaining oil condition, but does not address the fundamental importance of selecting the correct viscosity for initial lubrication.