Governors
The function of a governor is to regulate the mean speed of an engine, when there are variations in the load. e.g.
- When the load on an engine increases, its speed decreases, therefore it becomes necessary to increase the supply of working fluid.
- When the load on the engine decreases, its speed increases and thus less working fluid is required.
- Automatically controls the supply of working fluid to the engine with the varying load conditions and keeps the mean speed within certain limits.
- When the load increases, the configuration of the governor changes and a valve is moved to increase the supply of the working fluid.
- Conversely, When the load decreases, the engine speed increases and the governor decreases the supply of working fluid.
Applications of Governors
- Automobile Engines
- Steam Engines
- Internal Combustion Engines
- Turbines
Types of Governors
- Centrifugal governors
- Inertia governors
Centrifugal Governors:
The centrifugal governors are based on the balancing of centrifugal force on the rotating balls by an equal and opposite radial force, known as the controlling force.
Characteristics of Governors
1. Stability of Governors:
A governor is said to be stable when for every speed within the working range there is a definite configuration
For a stable governor, if the equilibrium speed increases, the radius of governor balls must also increase.
2. Sensitivity of Governors:
The smaller the change in speed from no load to the full load, the more sensitive the governor will be.
It is the ratio between speed range and mean speed. The smaller the ratio, the sensitive
the governor.
3. Isochronism:
A governor is said to be isochronous if equilibrium speed is constant for all the radii of
rotation in the working range.
4. Hunting:
A governor is said to be hunt if the speed of the engine fluctuates continuously above and below the mean speed.
This is caused by a too sensitive governor which changes the fuel supply by a large amount when a small change in the speed of rotation takes place.
