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#1 Amigatec OFFLINE  

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Posted April 08, 2013 - 12:22 PM

Ok I am planning to build a jack shaft to run my chipper with. If I make a shaft with a 4" pulley on one end and a 2" pulley on the other end, and spin the 4" pulley at a ratio of 1:1, will the 2" pulley have any change in RPM?
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#2 HowardsMF155 OFFLINE  

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Posted April 08, 2013 - 12:27 PM

The 2 inch pulley will spin at the same RPM as the 4 inch pulley.  


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#3 JRJ OFFLINE  

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Posted April 08, 2013 - 12:30 PM

I am not an engineer so I will have to agree with Hoiward, but using Pi it sounds like it should spin at twice the speed.

 

 

Dick 


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#4 bowtiebutler956 OFFLINE  

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Posted April 08, 2013 - 12:35 PM

 The pulley itself will be turning the same rpm, but whatever you are driving off the 2" pulley will be turning half the speed of your engine, because of the difference in diameter between the 2" and 4" pulleys.

 

Matt


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#5 HowardsMF155 OFFLINE  

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Posted April 08, 2013 - 12:35 PM

I am not an engineer so I will have to agree with Hoiward, but using Pi it sounds like it should spin at twice the speed.

 

 

Dick 

Using Pi only tells you how much distance one rotation of the pulley covers.  The rotation speed is independent of the pulley size in this context.  The speed change occurs when a pulley of say 12 inches around is connected to a pulley perhaps twice as big.  The little pulley has to spin around twice to cover the same distance the larger pulley travels in one rotation.

     Experiment with your tractor wheels, or with a truck and a trailer with small tires.  The ground is the equivalent of the belt hooking two pulleys together.


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#6 HowardsMF155 OFFLINE  

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Posted April 08, 2013 - 12:38 PM

 The pulley itself will be turning the same rpm, but whatever you are driving off the 2" pulley will be turning half the speed of your engine, because of the difference in diameter between the 2" and 4" pulleys.

 

Matt

Matt, don't make any assumptions.  Pat hasn't told us what diameter pulley he is driving with his two inch pulley.  If he drives another 2 inch pulley, the the final drive will spin just as fast as the engine.  If he drives a 4 inch pulley with the 2 inch pulley, the final drive will be half as fast as the engine.  If he uses the 2 inch pulley to drive a 1 inch pulley, the final drive will be twice the engine speed.


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#7 Texas Deere and Horse OFFLINE  

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Posted April 08, 2013 - 01:01 PM

Ok I am planning to build a jack shaft to run my chipper with. If I make a shaft with a 4" pulley on one end and a 2" pulley on the other end, and spin the 4" pulley at a ratio of 1:1, will the 2" pulley have any change in RPM?

 

Yes, Ratio will be about half on the 2" pulley. What RPM are you trying to get to?


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#8 Amigatec OFFLINE  

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Posted April 08, 2013 - 01:28 PM

If the engine is running at 3600 I believe the chipper should run at about ~2400.

The PTO is a 4" pulley, driving a 4" pulley, at the other end of the jack shaft is another pulley driving the rotor in the chipper. I am thinking a 2" pulley on the shaft and a 3" on the chipper.

I hope this makes since.

Edited by Amigatec, April 08, 2013 - 01:33 PM.


#9 ol' stonebreaker ONLINE  

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Posted April 08, 2013 - 02:38 PM

If the engine is running at 3600 I believe the chipper should run at about ~2400.

The PTO is a 4" pulley, driving a 4" pulley, at the other end of the jack shaft is another pulley driving the rotor in the chipper. I am thinking a 2" pulley on the shaft and a 3" on the chipper.

I hope this makes since.

 

  According to my math you'll wind up w/ 2400 chipper RPM. I will suggest going w/ a 6" pulley driven by the 4" PTO pulley to get the 2400 RPM and then one 6" each on the other of of the jackshaft and the chipper to give you more belt contact w/ all the pulleys to transfer more HP to the chipper. By getting the speed reduction on the PTO end V-belts transfer power better at higher rim speeds. 

                                           JMHO by working w/ with V-belt drives on rock crushers for too many yrs, LOL!!

                                                                         Mike

                                             


Edited by ol' stonebreaker, April 08, 2013 - 02:39 PM.

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#10 Amigatec OFFLINE  

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Posted April 08, 2013 - 03:51 PM

I was wanting to use a 4" pulley on the PTO, so I can use the same belt that snowthrower uses.

Also I have a piece of purlin that I want to use for a belt guard. It won't fit properly over a 6" pulley.

Edited by Amigatec, April 08, 2013 - 04:59 PM.

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#11 Texas Deere and Horse OFFLINE  

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Posted April 08, 2013 - 04:10 PM

If you use the 4" on both sides of the Jack Shaft and a 6" on the shredder will give you the same RPM at the shredder.


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#12 JDBrian OFFLINE  

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Posted April 08, 2013 - 06:23 PM

Those shredders use a lot of HP and will burn belts real easy. Using the larger pulleys will allow you to transmit more HP due to the larger surface area in contact with the pulley and lower force/torque due to the larger diameter. A 2" pulley would likely be too small for this application.


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#13 Amigatec OFFLINE  

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Posted April 08, 2013 - 07:09 PM

Ok that makes sense. That's the way I will make it.

The 59M has a 2 piece mount, I plan to make a 1 piece mount.

#14 IamSherwood OFFLINE  

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Posted April 08, 2013 - 07:14 PM

Here is a good link to keep handy.

 

http://www.culvermot...Calculator.html

 

Also, the belt length estimator (3rd one down on right side) works.


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#15 WHdbJD OFFLINE  

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Posted April 08, 2013 - 08:56 PM

OK,... I've read all these replies and now my head is spinning! :D






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