Gear Reduction
As the name implies, gear reduction
systems are used to reduce the output speed at the PTO while allowing the engine
to maintain a sufficient speed that will deliver the power required for the
application.
For example, an 8 H.P. engine used on a
cement mixer would likely require a constant speed of around 3600 RPM to deliver
peak power output. Obviously, the mixer itself cannot run at the same speed to
be effective, so a gear reduction system is used to reduce the RPM at the PTO
shaft. In this case, a 6:1 reduction system would output around 600 RPM (1/6th
the engine speed) which would be in the correct range for the application. The
internal gearing of the reduction unit also provides a massive amount of torque
(power) that would otherwise be unavailable to the application from the engine
alone.