What is the approximate rate of temperature rise per hour for the LO purifier heater when heating the Main Reduction Gear sump oil from 40°F to 90°F in one hour?

What is the approximate rate of temperature rise per hour for the LO purifier heater when heating the Main Reduction Gear sump oil from 40°F to 90°F in one hour?

• A. 50°F per hour
• B. 25°F per hour
• C. 60°F per hour
• D. 45°F per hour

Answer: (A)

Rate of temperature rise is simply the change in temperature divided by the time allowed. Here, the oil needs to go from 40°F to 90°F, which is a 50°F increase. Over one hour, that works out to 50°F per hour, assuming the heater delivers a steady heat input and heat losses are small. The other numbers would only fit if the final temperature, initial temperature, or the time were different—for example, a rate of 60°F per hour would reach 100°F in an hour, while 25°F per hour would only reach 65°F, and 45°F per hour would reach 85°F.

Rate of temperature rise is simply the change in temperature divided by the time allowed. Here, the oil needs to go from 40°F to 90°F, which is a 50°F increase. Over one hour, that works out to 50°F per hour, assuming the heater delivers a steady heat input and heat losses are small. The other numbers would only fit if the final temperature, initial temperature, or the time were different—for example, a rate of 60°F per hour would reach 100°F in an hour, while 25°F per hour would only reach 65°F, and 45°F per hour would reach 85°F.