The balls in Inertia Governor are arranged in such a way that the inertia forces caused by angular acceleration or retardation of the governor shaft tend to change their position.
Inertia Governor is more sensitive than centrifugal governor but in this governor, it is very difficult to completely balance the revolving part. So Inertia Governors are less frequently used than Centrifugal Governors.
The function of a governor is to regulate the mean speed of an engine.
Inertia is the property of matter by which it continues in its existing state of rest or uniform motion unless the state is changed by the external force. This property of matter is used by the balls of inertia governor in its operation. The two balls of the inertia governor is kept over a disc. These two balls are connected to each other by an arm . This arm connecting the two balls is pivoted and operates the throttle valve. The opening and closing of throttle valve is responsible for increase and decrease in fuel supply. Similar to spring loaded centrifugal governors, a spring is available on this governor to control the movement of the balls.
When the disc of the inertia governor rotates and when the speed of disc is increased or when the rotation of disc is accelerated, the balls moves in the opposite direction to the rotation of the disc. The movement of this ball in opposite direction is controlled by the spring available in the governor. As the balls moves in opposite direction, the arm connecting the balls also move . This arm operates the valve. So when movement of balls increases in opposite direction , the throttle valve closes and supply of fuel is reduced.
Similarly, when the speed of disc is decreased or the rotation of disc is retarded, the balls starts coming back to its original position. So the arm also moves and the throttle valve which is operated by the arm starts opening . Hence, the supply of fuel increases.
1) Highly sensitive to increase or decrease in load.
2) Quick response to change in load.
1) Difficult to completely balance the revolving parts.