Belt vs. chain drives

[Bern]

Need some thoughts and input on belt drives verses chain drive. Coming off the motor at about 2,000 RPM (max.), and going to a shaft at about 200 RPM. Motor is DC at about 2 HP. Which is best, considering: original cost, efficiency, noise, dependability, upkeep, etc. What would be the minimum sizes I could get away with?

[L. Daniel Rosa]

Wow! At that power there are arguments both ways. For price the belt may be a bit better at startup, but need replacing more often.<p>Belts may allow slip, and a cheater clutch can be improvised. Chains may require slop.<p>Belts prefer dry. Chains require wet (lubrication, and probably containment).<p>I think belts are a bit quieter when both are running properly, but really scream when they glaze.<p>At 2HP I'd look into the feasability of automotive belts and pulleys.

[bwts]

I agree with the above have a look at automotive belts, but would like to add that chain lengths can B cutomised and belt lengths come in standard sizes. Also chains R more hardcore as long as they R treated well (Loobed) but there can B problems when changing direction as tension is not constant thoughout the chain loop where as with a belt it is.<p>B)

[tallyjay]

Take a look at Fenner Drive belts. They are "link-belts" that can be customized to size by removing or adding lengths. I use them in a weapon system in a robot with approx 4 HP and have had no problems. Your bigger problem will be getting 10:1 reduction in RPM while maintaining large enough sheaves (pulleys) to transmit the needed HP.
You can find this from [url=http://www.mcmaster.com,]www.mcmaster.com,[/url] search on "twist lock belt".<p>tallyjay
www.bigbangrobotics.com

[Chris Smith]

Consider this in your decision making?<p>Cam shafts run at 10,000 Rpms and higher and work just fine with rubber bands, taking or using considerably more than 2 hp to drive.<p> Motor cycles use them as final drives replacing chains to the wheel, and have in excess of 100 hp forcing on them. <p>There is no question belts are superior, cheaper, reliable and are quieter.

[rshayes]

Belts are cheaper and quieter. Those are probably the reasons that they replaced timing chains in automative engines.<p>They are not more reliable. Replacing the timing belt somewhere around every sixty thousand miles is necessary, since a broken timing belt may result in substantial engine damage. The risk is fairly high that the belt will break before one hundred thousand miles.<p>The V belts used to drive the accessories on an engine (cooling fan, water pump, alternator, etc.) are even less reliable. I have had these break many times. The Corvair was especially bad in this respect. I doubt if I got over ten thousand miles on any belt on that car.<p>I have a car with a timing chain with over three hundred thousand miles on it, and no sign of trouble yet.<p>Whether a belt is superior depends on the application.<p>[ March 11, 2004: Message edited by: stephen ]<p>[ March 11, 2004: Message edited by: stephen ]</p>

[High4Volts]

It all application, application, application. But from what you describe. Would a serpentine drive belt work? It should be able to handle the HP and not slip. Many of these belts in industrial applications have steel belting inside ensuring no stretching. But using this setup will require specific pulleys for the belts. The operation will be quiet if the belt is tensioned right and not over sized. Is this something that will start and stop often? How fast will it accelerate from stop to full speed? There are lots of things to take into account for like, how much torque will be put on the belt, chain, pulleys or sprockets when it is started up? Things to make you say hmmmmmm….

[Bern]

Thanks for all the feedback that you have been sending. I found out that I need a little more than ten to one reduction. Now looking at a two-stage reducer, using a belt on the higher speed end, and a chain on the lower speed, higher torque, side of the system. In answer to a couple of the questions, it will be a soft, low acceleration start. Once running will be consistent for several minutes, to a couple of hours. Low start and stops, and/or reversing.

[Mr. K]

One final observation....<p>When things go south (as they inevitably will): V-belts slip, chains break stuff. How's your budget?<p>PS: I love the Fenners on my table saw!!