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Post by texaswoodie on Mar 11, 2009 6:05:18 GMT -5
If I have a motor with a 2 inch pulley and a shaft with a 4 inch pulley, would reducing the motor pulley have the same reduction as increasing the shaft pulley? Smaller pulley = less money. Curt
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,466
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Post by Sabre52 on Mar 11, 2009 7:55:53 GMT -5
Man Curt, I have puzzled over this exact question so many times. I'd answer yes because increasing the shaft pulley would slow the shaft speed were the motor pulley to stay the same size ( motor pulley would make more revolutions to drive the shaft pulley through one revolution). So making the motor pulley smaller would do the same thing ( more revolutions on motor pulley to equal one revolution of the shaft pulley). If you increased the motor pulley size, as the pulleys become closer and closer to the same size, the shaft pulley would rotate closer to the speed of the motor drive pulley....Mel
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Post by parfive on Mar 11, 2009 11:11:56 GMT -5
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Post by texaswoodie on Mar 11, 2009 13:29:13 GMT -5
Thanks Rich! It does make a big difference which is awesome because taking the shaft pulley off was going to be a great big pain.
Curt
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Post by Woodyrock on Mar 11, 2009 18:35:35 GMT -5
Curt:
The easy answer is yes, but you do have to take into consideration what the minimum diameter your belt can handle, which unfortunately is usually 2 or more inches.
Washington Woody
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Post by johnjsgems on Mar 11, 2009 19:02:33 GMT -5
Covington and Diamond Pacific both have pulley speed charts in their catalogs (available online). You are running 875 rpm per DP. The smallest motor pulley would likely be 1.5" which would give you 656 rpm. Increasing driven pulley by .5" would give you 778 rpm so no it would not be same ratio.
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docharber
has rocks in the head
Member since October 2008
Posts: 693
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Post by docharber on Mar 22, 2009 18:27:16 GMT -5
FOr paired pulleys, RPM times diameter opf the first pulley equals RPM times diameter of the second pulley. And for a 1/2 inch beltthe smallest pulley used should be 2" or more.
Mark H.
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Post by texaswoodie on Mar 22, 2009 18:59:40 GMT -5
Well, I put a 1 1/2 inch pulley on the motor and everything is working like a charm. So far.
Curt
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Post by Jack ( Yorkshire) on Mar 23, 2009 1:56:44 GMT -5
Hi The Formular is
M x P (dia) D (driven pully dia ) = RPM
Hope this is of help
Jack yorkshire UK
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