TO DETERMINE SPROCKET AND PUMP SPEED

• Find the diameter of the cart wheel in inches
• Divide the inches by 12 to get diameter in feet
• Next find the circumference of the wheel … C = 3.14 x diameter = x number of feet
• Next find how many revolutions the wheel turns per minute …

miles per hour x 5280 ft = x number of feet / C in feet / 60 minutes = x rev per minute

EXAMPLE:
Cart wheel measures 61.5 inches in diameter. Divide by 12 inches = 5.12 feet in diameter
Circumference then is 3.14 x 5.12 = 16 feet
If you are traveling at 5.5 mph, the revolutions of the wheel per minute is:
5.5 x 5280ft = 29040 ft traveled in 1 hour/ C of the wheel (16 ft) = 1815 rev per hour/60 min = 30 rev/min
To determine the sprocket needed to drive the pump at 350 to 450 rev/min you need to:

EXAMPLE:
You have a 48 tooth sprocket attached to the inside of the cart wheel.
It drops down to a 12 tooth sprocket to drive the seeding mechanism, therefore, the shaft on this part is turning…4 times faster than the wheel sprocket ( 30 rev/min x 48tooth/12tooth) = 120 rev/min

We need to be around 400 rpm for the ALPINE pump so we need it to be 400/120 or about 3.3 times faster. Since the sprocket on the pump is a 10 tooth, we would need to add a 35 tooth (#40) sprocket. Adding this size sprocket would then drive the pump at 120 rev/min x 35tooth/10tooth = 420 rev/min

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