B&G Network Autopilot - Manual (Page 47)

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ROTARY DRIVE SPROCKET WHEEL SELECTION
The number of teeth on the drive sprocket wheel must be chosen to
match each installation. The following guide may be used to select an
appropriate sprocket. The aim is to achieve a hardover to hardover time
of 10 to 12 seconds.
Note: The Rotary drive has a speed of 20 RPM or 1 revolution per 3
seconds or 3.7 revolutions in 11 seconds
• Turn the wheel from hardover port to hardover starboard and count
the number of turns of the driven sprocket
number of turns =N e.g. N = 3.1
• Divide 3.7 by N to give the required reduction ratio.
ratio = 3.7 / N e.g. ratio = 1.19
• Count the number of teeth on the Driven sprocket and divide by the
ratio to give the required number of teeth on the Driver sprocket.
driver teeth = driven teeth / ratio
e.g. if driven teeth = 25
driver teeth = 25 / 1.19 = 20.9
• Select a sprocket with the number of teeth closest to calculated value
e.g.
select driver sprocket with 20 teeth