belt and pulley system 1

[Zalic]

Hi! I have 2 pulleys and belt. My belt is damaged and new belt with this size can buy. I have belt which is 4 mm longer. I cant move pulleys to strain the belt. So i must take one pulley a little bit bigger. But i don't known how much bigger i need. Maybe someone can help?

 

[Walterke]

what's the total length of the belt?

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[Zalic]

now was 352mm PJ profile now will be 356mm PJ profile

 

[Walterke]

Are you sure the 4mm difference will be a problem?
I find it kinda hard to believe that a 1% change in belt length will have any substantial influence on your machine.

NX 7.5.5.4 with Teamcenter 8 on win7 64
Intel Xeon @3.2GHz
8GB RAM
Nvidia Quadro 2000

 

[Zalic]

its for air compressor. Old belt start slip. I think the new from the beginning will slip. Yes of course I can try, it's not a problem, maybe it will work but i doubt. But I can put something on the pulley to get him bigger

 

[Walterke]

Not my area of expertise, but look at the old belt, perhaps measure it to see if it elongated during use and see what kind of wear is causing it to slip.

NX 7.5.5.4 with Teamcenter 8 on win7 64
Intel Xeon @3.2GHz
8GB RAM
Nvidia Quadro 2000

 

[btrueblood]

What kind of pulley/belt are we talking about? You can't easily build up a v-belt pulley. It's possible to wrap a flat belt pulley. It's not possible at all to build up timing belt pulley.

 

[btrueblood]

Does the motor or compressor have the capability of moving to increase/decrease belt tension? This is the mechanism that should be used to take up slack. Or, install a spring-loaded belt tensioner (i.e. an idler pulley mounted on a spring-loaded arm).

 

[zekeman]

Give us the diameters of the 2 pulleys, and the one you want to increase. Simple trig or lookup.
L=2C+1.57(D2+D1)+(D2-D1)^2/4C
C center distance between pulleys
D1,D2 pulley diameters
L belt length

For a change of pulley diameter, D1 I get
change in L=(1.57-D1/2C)*change in D1

 

[rb1957]

if the compressor doesn't have a tension adjustment, maybe it'd be a good thing to add.

you'd add a idler wheel about the mid of the belt run, welded to the compressor case, ideally in the plane of the belt run.
adjust the position of the idler with an internal/external thread (or a turnbuckle) to maintain belt tension.

clear as mud ?

 

[Zalic]

The compressor doesn't have a tension adjustment. I found belt in Czech web shop. I think about made something like tension adjustment
Thanks for the math formula

 

[Tuckabag]

If there's no tension adjustment (which I find hard to believe) you could re-mount the motor on some spacers to move it further away from the compressor pulley.
Or ideally as others have suggested make a tensioner system, either provide a pivot for the motor or an idler wheel.

 

[hydroman247]

One of our small portable compressors at work has a belt and pulley system with no tensioner. The motor is mounts are slotted allowing for tensioning the belt. Also a small flange with a bolt and nut pushing the motor away from the pump to take the strain off the actual mounting bolts.

 

[Tmoose]

I >>really<< expect to find an adjustment in there somewhere.

Some v-belt pulleys/sheaves are split and come with an assortment of shims. air cooled VW beetles, early Volvos, undoubtable others. Installing the shims between halves makes the sheave wider and act like a smaller diameter. Moving some shims from between the halves to the outside makes the sheave narrower and act like a larger diameter.

http://www.volksworld.com/wp-content/uploads/2012/08/11117000001dc05d51_step27.jpg