Belt / pulley engineers
 

Is there a rule of sorts for power losses on a pulley?
I checked google for a hour.......sort of got lost...they did 90 deg turns......
Just pulley to pulley........
Is there A rule of thumb of sorts per belt?
thanx!

Use suspenders not a belt and your pants don't lose any power. For ultimate power use both a belt and suspenders!

wow........................This used to a place of great thought.

You would have a coefficient of friction between the belt/pulley, which would be a function of materials, interface, and belt tension. That would be one way to calculate the losses, though guys that do it for a living probably have a more clever way.

Rule of thumb:
1. V-belt will loose more than flat-belt.
2. The more "bends" you do the more power you loose.

For every 2 pulleys you lose 288.

OP - wide open that leads to a 1000 questions with a 10000 different answers. For example, cogged belt (as in an engine timing belt) vs. V type smooth vs. V w/notched....

For start > Belt Tension Theory: Factors

Timing belts > http://apps.gatesmectrol.com/applications/doc/Belt_Theory.pdf

V belts
this particular application runs about 7 pulleys
engine, jack shaft,
then sprocket 15 pound chain to a HUGE sprocket (to gear it all dwn)
I can do this with one drive shaft, and a ring gear (ring and pinion type )
I am thinking this would be so much simpler get rid of a bunch of stuff

Took a few seconds to find this

TUTORIAL – PULLEY DRIVE SYSTEMS


It is not a simple exercise, It is a dynamic system with many variable..Your going to need some good math skills, DiffEq's etc..


This is also some light reading on the subject

WOW
and thanx
Some one was a genius to come up with this belt system.....
I think one more tweek is to get rid of it all togther

What's the transmission loss of your drive shaft idea? How much weight will your application add for a drive shaft and ring gear sized to take the stress compared to the weight of the pulleys and belts? Adding weight results in power loss as well.

Are there multiple speeds involved with driving individual components off the pulleys?

How are you going to keep that drive shaft lubed? How many hours are you going to get on that drive shaft before the lash wear is out of spec? What will be needed to R/R that drive shaft as opposed to R/R belts?

Sometimes engineering is not driven entirely by complexity or the number of components used.

Right now the system is toast between 1oo and 200 hours
A simple ring gear arrangement will weigh no more, should out last all other components involved.
I do appreciate everyone's help.
If in a car loses are 10 to 15% through a simple drive train. these belts is a parasitical nightmare .
Plus all the adjusting all the time

I have all that info in some books in my office, it'd prolly take an hour to find all the info to answer your questions given that there are a go-zillion variables.

Are you talking about a standard V belt? Which size, A,B,C,D, DD? Yeppers just like bras.

Pitch diameter of each shieve, RPM of smallest, etc.
Number of belts, seperated or banded?
Or are you referring to a serpantine belt?
Which belt manufacturer?

I'm not aware of any general rule of thumb that applies to all V belts. Life ain't that simple in my world. Too damn many variables.

BUT, I will say that a properly designed and installed belt system can reach 95% efficiency and should always be over 90% efficient or someone screwed up.

Yes

Energy Loss and Belt Efficiency

Yes

Just saw this. Reminds me of some old nightmare papermills I worked in as a kid.
Needs some serious engineerin'.

Thanx
i could live with a couple belts.......but OMG!
From engine to 1st jackshaft its a set of 4
thats right, engine shaft with 4 pulleys to jackshaft again 4 pulleys
they are about 6 inches across on the jack. maybe 4" on the engine...i understand they were stepping torq up and RPM dwn........
I am thinking cause they are "V" belts...there is a loss right there...

A ring gear would be a solid coupling whereas the belts/pulleys have more compliance.

Best guess:
Large lightweight balanced pulleys(aluminum/mag) using the same overall ratio, thin flat ribbed belt, add tensioners where needed to make the path round but flexible under heavy load.

A long shaft to the back of a helicopter would/could have plenty of compliance. I actually would worry about too much compliance without extra bearings, especially when pulling g's or in turbulence.

http://forums.pelicanparts.com/uploa...1389148932.jpg

But I guess he must be talking about shafts directly from the engine/transmission rather than with some layshafts.

A shaft with compliance is not a shaft, it is a torsion bar.