A Wilson-Hartnell governor is illustrated in given Figure. In this, the balls are associated by two springs that are known as main springs. The main springs are symmetrically arranged on either side of the sleeve. The balls are associated to the vertical arms of the two bell-crank levers.
The horizontal arms of bell-crank levers hold two rollers at their ends.
At the horizontal arm the rollers press against the sleeve. The bell-cranks rotate along the spindle.
While speed enhances the ball-radius reduced, the springs exert an inward pull P on the balls and the rollers press against the sleeve that is raised
Attachment:- Wilson.rar