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 auxilary engine governor, what is the significance of: (8)
(i) The Load limit knob
(11) The compensaiton
Class 4 (4th Engineer)
MEKM
📅 May 2024
Reference Answer
### (a) Necessity of an 'Over-speed' Trip Despite a Governor
An over-speed trip is a mandatory, independent safety device fitted to a marine diesel engine, distinct from the governor, which is a primary speed control system. The fundamental reason for its installation is to protect the engine and personnel from the catastrophic consequences of uncontrolled over-speeding in the event of a governor system failure.
**1. Differentiation of Function:**
* **Governor:** A regulating device designed to maintain the engine's speed at a set point under varying loads by continuously modulating the fuel supply. It is an active, primary control system.
An over-speed trip is a mandatory, independent safety device fitted to a marine diesel engine, distinct from the governor, which is a primary speed control system. The fundamental reason for its installation is to protect the engine and personnel from the catastrophic consequences of uncontrolled over-speeding in the event of a governor system failure.
**1. Differentiation of Function:**
* **Governor:** A regulating device designed to maintain the engine's speed at a set point under varying loads by continuously modulating the fuel supply. It is an active, primary control system.
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