Question 45 UFIV02 - Assistant Engineer - UFIV

The Correct Answer is B **Explanation for Option B (Correct):** Option B states: "To adjust the over speed trip, the engine must be stopped AND the locknut must be retightened after each adjustment." This statement reflects standard and safe engineering practice for adjusting mechanical safety devices like engine overspeed trips, especially those involving flyweights and spring tension (as is typical in the illustrated mechanism MO-0101). 1. **Engine Must Be Stopped:** Adjustments to the physical mechanism (changing spring tension or weight position) must be made while the engine is stationary. Attempting to make precise adjustments to critical moving parts on a running engine is extremely dangerous and could lead to catastrophic failure, injury, or inaccurate settings. Safety adjustments are always performed statically. 2. **Locknut Must Be Retightened After Each Adjustment:** Since the adjustment requires running the engine up to speed after each physical change (to test the new trip point), the adjustment screw (or similar mechanism) must be securely locked down using the locknut before the test run. Vibration from the running engine could cause an unsecured adjustment to shift, leading to an inaccurate test or an unexpected trip (or failure to trip) at a critical time. Since multiple adjustments are anticipated, the locknut must secure the setting before *every* test run. **Explanation for Why Other Options are Incorrect:** * **A) To adjust the over speed trip, the engine must be running AND the locknut must be retightened after each adjustment.** * **Incorrect:** The physical adjustment cannot safely or accurately be performed while the engine is running. The mechanism must be accessed statically. * **C) To adjust the over speed trip, the engine must be stopped AND the locknut must be retightened only after the final adjustment.** * **Incorrect:** While the adjustment must be made when the engine is stopped, failing to retighten the locknut before testing the setting (running the engine) is unsafe. The setting could drift due to vibration during the test run, rendering the test results unreliable or causing damage. * **D) To adjust the over speed trip, the engine must be running AND the locknut must be retightened only after the final adjustment.** * **Incorrect:** This option combines two major safety violations: attempting adjustment on a running engine, and failing to secure the setting before test runs.