TERMINOLOGY USED IN GOVERNORS

There are some general terms used in governors that describe qualities of governor. These terms are as follows:

• Height of governor: It is the vertical distance between the centre of the governor balls and the point of intersection between the upper arms on the axis of spindle. It is generally denoted by h.
• Equilibrium speeds: The speeds at which the governor balls, the arms, etc., are in complete equilibrium and the sleeve does not tend to move upward or downward are called the equilibrium speeds.
• Sleeve lift: The vertical distance the sleeve travels due to change in the equilibrium speed is called the sleeve lift. The vertical downward travel may be termed as negative lift.
• Effort and power of a governor: A governor running at a constant speed is in equilibrium and the resultant force acting on the sleeve is zero. If the speed of the governor increases there is a force on the sleeve which tends to lift it. This force will gradually go on decreasing till the governor starts rotating in equilibrium at the new position of rotation. The mean force acting on the sleeve for a given change of speed or lift of the sleeve is known as the governor effort.
• Controlling force: The force acting radially inward upon the rotating balls to counteract its centrifugal force is called the controlling force. It is provided by weight on the sleeve or compressed spring.
• Isochronism: This is an extreme case of sensitiveness. When the equilibrium speed is constant for all radii of rotation of the balls within the working range, the governor is said to be in isochronism. This means that the difference between the maximum and minimum equilibrium speeds is zero and the sensitiveness shall be infinite.
• Hunting: The phenomenon of continuous fluctuation of the engine speed above and below the mean speed is termed as hunting. This occurs in oversensitive or isochronous governors.
• Sensitiveness: A governor is said to be sensitive, if its change of speeds from no load to full load may be as small a fraction of the mean equilibrium speed as possible and the corresponding sleeve lift may be as large as possible