
278 LIGHT AND HEAVY VEHICLE TECHNOLOGY
The operation of this type of two-stage governor is
such that as the output shaft begins to rotate with
movement of the vehicle, both flyweights tend to move
outwards because of centrifugal force acting upon them.
This action pulls the control valve inwards so that the
port admitting fluid at line pressure starts to uncover
and meters fluid at governor pressure. As the vehicle
continues to gain speed, the flyweights will move further
out until the outer one approaches its retaining ring,
but the increasing governor pressure that is acting on
the larger spool of the valve compresses the spring to
restrai ...