Vanes 1 and spring 2 are linked to shaft A whose speed is to be governed. Vanes 1 have pivots B on which levers 3 with blades b and weights c turn. The swinging motion of levers 3 is limited by pins d sliding in slots a of vanes 1. When the speed of the shaft increases, weights c are forced outward, turning levers 3 about pivots B. This increases the moment of the resistance of the air to rotation, thereby governing the angular velocity of shaft A.
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