Exam Question
(a) Why do you need an 'over-speed' trip despite a governor being fitted to a marine diesel engine? (8)
(b) With respect to an auxiliary engine governor, what is the significance of: (8)
(i) The Load limit knob
(ii) The compensation
Class 4 (4th Engineer)
MEKM
📅 Nov 2024
Reference Answer
### (a) Why do you need an 'over-speed' trip despite a governor being fitted to a marine diesel engine?
Despite the presence of a governor, an over-speed trip is an indispensable safety device on a marine diesel engine due to the critical nature of its function as a final safeguard against catastrophic engine failure. While a governor is designed for precise speed regulation under varying load conditions, it is not an emergency shutdown system. The over-speed trip acts independently and is activated when the engine RPM exceeds a pre-set safe limit, typically 10-15% above the maximum rated speed.
The necessity of an over-speed trip arises from several potential failure scenarios that a governor, by its design and operational scope, cannot adequately address:
* **Governor Malfunction or Failure:**
Despite the presence of a governor, an over-speed trip is an indispensable safety device on a marine diesel engine due to the critical nature of its function as a final safeguard against catastrophic engine failure. While a governor is designed for precise speed regulation under varying load conditions, it is not an emergency shutdown system. The over-speed trip acts independently and is activated when the engine RPM exceeds a pre-set safe limit, typically 10-15% above the maximum rated speed.
The necessity of an over-speed trip arises from several potential failure scenarios that a governor, by its design and operational scope, cannot adequately address:
* **Governor Malfunction or Failure:**
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