The Jalopy Journal
Discussion in 'The Hokey Ass Message Board' started by kylejones, Jun 27, 2013.
Pulleys are only a few bucks each and easy to change, just go buy a couple more of different sizes and try them out until you're in range. Have you tried just reversing the pulleys that are on it?
By my calculations, you are running at 2678 ft/min now, so you need an additional 12 to 1 reduction. your 2.5" pulley would require a 30" mate. I would increase the 5.5" pulley to 12", then the 30" pulley would be reduced to about 15". You might want to consider a double jack shaft.
The ratio of 2.5:5.5 is 0.4545
Apply that ratio to your motor RPM and you get 1725 x 0.4545 = 785 RPM
So if you are moving the 13 inch wheel at 785 RPM the blade is moving at:
13 x pi x 785 = 32,060 inches per minute
32,060/12 = 2672 ft/min
The circumference of your drive wheel is 13 inches x pi = 40.84 inches or 3.4 feet
To get the 225 feet per minute you want you need to divide the 225 by 3.4 which equals around 66 RPM.
So now you need a ratio that will give you the 1725:66 reduction which works out to around 66:1 So if you keep the 2.5 inch pulley on the motor you will need a 2.5 x 66 pulley on the drive side to get to the 66:1 reduction...this means you need to replace the 5.5 pulley with a 165 inch pulley
That does not sound reasonable so you need to start looking for a smaller motor pulley and a drive pulley that will give you the 66:1 ratio
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