Difference between governors fitted on main propulsion engine and Generator.
All marine vessels need some sort of speed control system to control and govern the speed of marine diesel engine used for propulsion. It would be really impractical and dangerous to have a ship without speed control mechanism fitted on it, and can lead to accidents such as collision or grounding. The speed control mentioned above is achieved with the help of a governor. Main role of a governor is not to increase or decrease the speed which can be done via fuel control system ( similar to an accelerator on your car) but once the speed of the engine has been set, the job of the governor is to maintain that despite the variations in load. In other words the governor controls the speed variation and keeps the speed within restrained limits despite these variations. As per IACS each main engine is to be fitted with a speed governor so adjusted that the engine speed can not exceed the rated speed by more than 15%. Generator on board a ship needs to maintain constant freque