Section 2. Principles Of Operation; Output Rotation; Reduction Ratio; Power Flow - CAPITOL HY- 6900 Service Manual

SECTION 2. PRINCIPLES OF OPERATION

2.1 OUTPUT ROTATION

The capitol marine gear in forward mode
provides output rotation in the opposite
direction as engine rotation. The marine
gear unit is normally supplied for a right
hand engine (when viewed from the front).
This produces a right hand rotation output of
the prop shaft in forward (When viewed from
the rear of the transmission.) For twin-screw
installations, where two right hand engines
are used, the port unit is furnished with an
idler gear. The idler gear produces, in
forward, an output rotation the same as
engine rotation. Thus the two propellers can
be turning opposite each other in outboard
direction (see diagram below). Note: Engine
rotation transmissions are installed on right
hand engines only.

2.2 REDUCTION RATIO

The reduction ratio is the number of teeth in
the reduction gear compared to the number
of teeth in the pinion, for example, 144 teeth
compared to 36, or 4 to 1. Output speed
then is a product of engine r.p.m and the
reduction ratio, for example 200 r.p.m. X ¼
= 500 r.p.m output speed.

2.3 POWER FLOW

The flywheel adapter, being directly
fastened to the engine flywheel continually
rotates the drive flange assembly, clutch-
driving drum and forward clutch discs at
engine speed.
NEUTRAL
In neutral no direct torque is applied
to clutch and pinion. Consequently
reduction gear and output flange do
not rotate.
FORWARD (See figure 2.)
When forward is selected the entire
clutch becomes locked with the
driving drum and rotates at engine
speed. The clutch drives the pinion
in engine direction and the pinion
drives the reduction gear and output
flange in anti-engine direction at a
speed determined by the reduction
ratio.
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