• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

What's better for medium speed?

Rubycon

Rubycon

Madame President
Chain and sprocket vs. twin v-belt vs. poly-v belt?

Speed on small (driving) sheave not to exceed 3500 rpm, flywheel speed about 750 rpm.
 
How much torque and how much resistance?

The issue with V-belts of any sort is the potential for slippage. On the other hand, they are quieter than chains and don't require lubrication.

Have you considered a Gilmer belt instead of a V-belt?

ZV
 
Howard said:
Isn't a Gilmer belt just a timing belt?
Click to expand...

A Gilmer belt has teeth, a V-belt does not. Because of this, a Gilmer belt won't slip like a V-belt can, which makes it possible to use a Gilmer belt in situations where using a V-belt is inadvisable. They can handle more torque than V-belts but still have the advantage over chains by being quieter and not requiring lubrication. A chain is ultimately stronger, but in most cases a Gilmer belt is plenty strong.

ZV
 
Zenmervolt said:
How much torque and how much resistance?

The issue with V-belts of any sort is the potential for slippage. On the other hand, they are quieter than chains and don't require lubrication.

Have you considered a Gilmer belt instead of a V-belt?

ZV
Click to expand...

Timing is not essential so slippage will NOT cause malfunction. This would be approx 5hp but could be scaled to a larger (250hp) design.

Belt slippage at start up is anticipated. Since the motor is across the line a chain could be dangerous or just get too loose after a few 100 starts/stops?
 
Rubycon said:
Timing is not essential so slippage will NOT cause malfunction. This would be approx 5hp but could be scaled to a larger (250hp) design.

Belt slippage at start up is anticipated. Since the motor is across the line a chain could be dangerous or just get too loose after a few 100 starts/stops?
Click to expand...

Even with a belt, you'd want some form of tensioner. As long as you don't have a huge amount of resistance on the 750 RPM side, a dual v-belt would probably suffice, same with a simple flat ribbed belt.

On the other hand, there's a reason why motorcycle belt drives use Gilmer belts and not V-belts even though timing isn't critical; a V-belt just cannot transmit enough torque in high-load situations. Still, having some slip at start-up is a good way of reducing the stress on the belt/chain fro mthe sudden application of torque.

As long as you can set up a V-belt system where you're not experiencing constant slip, that would probably be the direction I'd go, with at least some form of manual mechanical tensioning through an idler pulley so you could check and re-set the tension every so many stops/starts. You'll also want to figure out the expected lifespan of the belt, but I figure you have that in hand already.

ZV
 
Zenmervolt said:
A Gilmer belt has teeth, a V-belt does not. Because of this, a Gilmer belt won't slip like a V-belt can, which makes it possible to use a Gilmer belt in situations where using a V-belt is inadvisable. They can handle more torque than V-belts but still have the advantage over chains by being quieter and not requiring lubrication. A chain is ultimately stronger, but in most cases a Gilmer belt is plenty strong.

ZV
Click to expand...
A V-belt is not a timing belt. This is a timing belt:

http://img.alibaba.com/photo/51281972/Industrial_Timing_Belt.jpg

I've never seen a V-belt used in a non-low-power application, so:

Chain:

+ cheaper
+ lasts longer
+ more space efficient (power transmission density)
- can require maintenance (lubrication, mostly)
- louder
 
Last edited:
Yes tension becomes a problem as it can wear the bearings too rapidly if too tight and it too loose the belt will start slipping as power ramps up.

Starting is just overcoming dead mass since the pump has to be unloaded.

A pair of 4L belts should be plenty for 5hp or so.

Zenmervolt said:
Well, when the Gilmer belts used as timing belts in my cars slip, it sounds like money flying away. 😱

ZV
Click to expand...

Don't they just break though? Must suck if you have interference engines!

Now I remember what it sounds like. A screw compactor had one that was jammed and the belt slipped. Sounds like growling and that was probably a 1hp motor!
 
Last edited:
Howard said:
A V-belt is not a timing belt. This is a timing belt:

http://img.alibaba.com/photo/51281972/Industrial_Timing_Belt.jpg
Click to expand...

Nope, that's a Gilmer belt. 😛 😉

"Timing belt" technically specifies an application, not a specific type of belt. Theoretically, you could use a V-belt as a timing belt; it would just be a really bad idea.

I rambled more than I should have in my previous answer. Gilmer belts are essentially what are universally used for timing belts, so yes, a Gilmer belt is what people tend to think of when someone uses the phrase "timing belt" colloquially to refer to a type of belt rather than an application. In most automotive engines, Gilmer belts are used for either cam timing or for balance shaft synchronization.

ZV
 
Rubycon said:
Don't they just break though? Must suck if you have interference engines!

Now I remember what it sounds like. A screw compactor had one that was jammed and the belt slipped. Sounds like growling and that was probably a 1hp motor!
Click to expand...

Actually, it's very rare that they snap. Usually they simply shear a few teeth due to the rubber aging. The reinforcements in modern belts mean it's very rare for one to simply let go.

As far as interference engines, many (most?) automobiles today are interference engines. The interference design allows more power and better efficiency, so it has become popular.

ZV
 
Zenmervolt said:
Nope, that's a Gilmer belt. 😛 😉

"Timing belt" technically specifies an application, not a specific type of belt. Theoretically, you could use a V-belt as a timing belt; it would just be a really bad idea.

I rambled more than I should have in my previous answer. Gilmer belts are essentially what are universally used for timing belts, so yes, a Gilmer belt is what people tend to think of when someone uses the phrase "timing belt" colloquially to refer to a type of belt rather than an application. In most automotive engines, Gilmer belts are used for either cam timing or for balance shaft synchronization.

ZV
Click to expand...
I'm pretty sure you're the only person alive that would include V-belts as a subset of timing belts. Even stipulating your definition that a timing belt is a belt used for timing, a V-belt simply does not. Cannot.
 
Howard said:
I'm pretty sure you're the only person alive that would include V-belts as a subset of timing belts. Even stipulating your definition that a timing belt is a belt used for timing, a V-belt simply does not. Cannot.
Click to expand...

That would be why I said it would be a really bad idea to use a V-belt as a timing belt. 😉

It's kind of like the same way that you could use a dodecagon as a wheel, it just won't work very well. I think perhaps my attempted humor was a bit too dry in this instance.

In any case, for all practical purposes, all timing belts are Gilmer belts, but not all Gilmer belts are timing belts.

ZV
 
Rubycon said:
Yes tension becomes a problem as it can wear the bearings too rapidly if too tight and it too loose the belt will start slipping as power ramps up.

Starting is just overcoming dead mass since the pump has to be unloaded.

A pair of 4L belts should be plenty for 5hp or so.



Don't they just break though? Must suck if you have interference engines!

Now I remember what it sounds like. A screw compactor had one that was jammed and the belt slipped. Sounds like growling and that was probably a 1hp motor!
Click to expand...
That compactor should've had a shear coupling.
 
Howard said:
That compactor should've had a shear coupling.
Click to expand...

There was a high current limit on the motor but it was jumped out because it kept tripping. 😀

Hydraulic compactors are better but I have to admit the vertical screw method is super simple.
 
Rubycon said:
There was a high current limit on the motor but it was jumped out because it kept tripping. 😀

Hydraulic compactors are better but I have to admit the vertical screw method is super simple.
Click to expand...

displacement control vs load control. all depends on which one you want 🙂
 
Howard said:
A V-belt is not a timing belt. This is a timing belt:

http://img.alibaba.com/photo/51281972/Industrial_Timing_Belt.jpg

I've never seen a V-belt used in a non-low-power application, so:

Chain:

+ cheaper
+ lasts longer
+ more space efficient (power transmission density)
- can require maintenance (lubrication, mostly)
- louder
Click to expand...

Chains require much more maintenance than belts IMHO. Aside from constant lubrication, chains stretch and require tension adjustment just like belts. However, you also have to account for sprocket wear and they are much less forgiving on alignment.

Depending on the application, a good belt setup (either cog or V) will work fine as long as the belts are properly maintained (tensioned) and the sheaves don't get subjected to excessive wear.

The primary issue with belts (IMHO) is improper maintenance. Sheaves wear out and tend to get "overused", the systems rarely get proper alignment, they are rarely tensioned properly and quite often improperly replaced with unmatched sets or single belts out of a group.
 
Gillbot said:
Chains require much more maintenance than belts IMHO. Aside from constant lubrication, chains stretch and require tension adjustment just like belts. However, you also have to account for sprocket wear and they are much less forgiving on alignment.

Depending on the application, a good belt setup (either cog or V) will work fine as long as the belts are properly maintained (tensioned) and the sheaves don't get subjected to excessive wear.

The primary issue with belts (IMHO) is improper maintenance. Sheaves wear out and tend to get "overused", the systems rarely get proper alignment, they are rarely tensioned properly and quite often improperly replaced with unmatched sets or single belts out of a group.
Click to expand...

Yes the edges of a sheave should not be so thin they cut like a knife. 😉
 
You must log in or register to reply here.

TRENDING THREADS

Back
Top