Power Transmission help converting V belt to roller chain

I have not been able to run a BX22 belt for any length of time on my hot water pressure washer. I had always assumed it was the work the belt was having to do wrapping my smaller 3.15" pulley on my generator. I have had the most luck running Optibelt Super TX BX22's but rarely get more than 4 months out of them. I made a switch to a lesser brand due to easier availability and cost savings. That turned out to be a horrible idea as the last two belts only ran 41 hours and 1.5 hours. I'm currently running a un notched wrapped V belt with Kevlar cords but I seriously doubt it will be a more reliable solution than the Optibelt's I have previously run.

I'd like to run the generator with sprockets and chain. I've looked around on various sites and McMaster Carr and I'm a bit out of my realm and would greatly appreciate your help in making the transition.

I don't think you are overpowering the belts. I suspect you have an alignment issue that makes it so the belts aren't sharing the load.

Belts are much more forgiving about alignment than chains are.

I have fixed problems like that by either adding an independent tensioner and lining up the shafts precisely or by re making whatever guides the moving element so it stays straight or can be forced straight during adjustment. One trick I've used a few times is to use a few steel bar pieces with a corner milled out. Weld these onto the flimsy base with close fitting T-nuts inside. If everything fits close the T-slots will be precise enough to maintain alignment where the junky punched slots it came with were not good enough.

Hey thank you for your reply, I appreciate it. I'm losing that smaller belt due to heat that's generated from wrapping that small pulley on the generator or from the heat that's migrating over from the generator head. The alignment is dead on. I'm done with those baby V belts but I only know two things about sprockets and chains

The B hub type sprockets I'm finding have a HUGE hub diameter that would not likely sit inside the recess of my pulley that drives my pump. Although I do have to grind a few thou off the BK45 that drives the generator so it sits flush against the other pulley but at that point I'm not left with very much purchase on the PTO

Why not toothed belts ?

I'd suggest increase all the pulley diameters to get better traction.

I don't think a chain will last very long at high speed, and would need constant adjusting as it wears.

With all due respect, if you are dead set on using chain then I think it would work. I have seen some chains going pretty darn fast with no real adjustment problems. Think motorcycle.

Going to a roller chain with no lubrication at the speed it runs won't last. A better solution would be a Gates Polychain.

You didn't say if the pump belts were lasting and the generator belt is the only one going bad. I would look to see if alignment or some other problem is causing unnecessary drag. If this is an original factory set up then the belt should be sized correctly. A B belt will transmit quite a bit of power. Pulleys don't appear to be to small.

Hard to tell looking at the size of the generator but doesn't appear to large for a B belt. Heat kills ,so alignment and correct tension are important. Worn pulleys affect belt life especially if the belt bottoms out but yours don't appear to.

It's easy to figure the load if you know the output and speed. Most belt manufacturers have tech sections online that will show you how calculate the correct belts.

So if this is a non factory set up then you need to recalculate. If a single B is undersized for the load the go duel belts or a Polychain. All this is just speculating not having the machine at hand.

Cogged or Notched?

HuFlungDung said:

I'd suggest increase all the pulley diameters to get better traction.

I don't think a chain will last very long at high speed, and would need constant adjusting as it wears.

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That would put me close to 6" on the drive pulley for the generator. I'm not opposed to it but I want it fixed for good as I already battle other electrical mechanical issues on the machine. It's used commercially and I have to stop toying around with temporary fixes

ratbldr427 said:

Going to a roller chain with no lubrication at the speed it runs won't last. A better solution would be a Gates Polychain.

You didn't say if the pump belts were lasting and the generator belt is the only one going bad. I would look to see if alignment or some other problem is causing unnecessary drag. If this is an original factory set up then the belt should be sized correctly. A B belt will transmit quite a bit of power. Pulleys don't appear to be to small.

Hard to tell looking at the size of the generator but doesn't appear to large for a B belt. Heat kills ,so alignment and correct tension are important. Worn pulleys affect belt life especially if the belt bottoms out but yours don't appear to.

It's easy to figure the load if you know the output and speed. Most belt manufacturers have tech sections online that will show you how calculate the correct belts.

So if this is a non factory set up then you need to recalculate. If a single B is undersized for the load the go duel belts or a Polychain. All this is just speculating not having the machine at hand.

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Thank you so much for your help on this. My pump belts run a bit more off from perfect than the single generator belt but you can't tell unless you use a straight edge on it. They last over a year on the pump side. All pulleys have been replaced, I typically run two sets of belts then swap out the pulleys for new.

The generator is a 2kw but I only put a 1/4 of a load on it. I believe a BX belt is plenty for it as it's only using about 2hp off the engine to run. I'm a tad bit familiar with the Poly chains but I'll need to research the sprockts for them to see if they can be a option.

Notched vee belts will run cooler grip better and are less apt to roll over or twist due to the lower inertia of the inside diameter. They are mostly all premium belts; the reinforcement cords are all on the od just under the cover.

The draw back to a polychain is the width. Since they don't slip they run cooler. I use them whenever I can and if I can replace a roller chain with them I do.

The best industrial chain I've run across is Tsubaki Lambda. Similar to a motorcycle(prelubed bushings) o'ring without the o'rings. Tsubaki claims up to 10 times more life than a standard chain. I have one application where it has proven true. Lack of lube is what kills chains. We have some older machines that the chains are 30/40 years old. Medium speed but run in an oil bath.Drain the oil and they would be gone in less than a week.

When we got our first KBA Rapida press I found that there was a 10mm Polychain in the gear side running in splash oil. I was thinking what dumaas German engineer thought that will last. We got rid of it ten years later with almost 1 billion impressions on it and never had to replace any(seven on each machine).

500kw load is only approx 2/3 hp. B belt should be more than ample?

ratbldr427 said:

Notched vee belts will run cooler grip better and are less apt to roll over or twist due to the lower inertia of the inside diameter. They are mostly all premium belts; the reinforcement cords are all on the od just under the cover.

The draw back to a polychain is the width. Since they don't slip they run cooler. I use them whenever I can and if I can replace a roller chain with them I do.

The best industrial chain I've run across is Tsubaki Lambda. Similar to a motorcycle(prelubed bushings) o'ring without the o'rings. Tsubaki claims up to 10 times more life than a standard chain. I have one application where it has proven true. Lack of lube is what kills chains. We have some older machines that the chains are 30/40 years old. Medium speed but run in an oil bath.Drain the oil and they would be gone in less than a week.

When we got our first KBA Rapida press I found that there was a 10mm Polychain in the gear side running in splash oil. I was thinking what dumaas German engineer thought that will last. We got rid of it ten years later with almost 1 billion impressions on it and never had to replace any(seven on each machine).

500kw load is only approx 2/3 hp. B belt should be more than ample?

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Hey thanks for replying. I have been running notched belts for many years on this machine. Those little BX22 belts just don't last on this machine! It's not from it being out of alignment, improper tension or contamination. I'm telling you guys they are cracked in the valleys of the notches with the cut edges glazed over and maybe missing a chunk of notches if I don't catch it soon enough. It's always a constant maintenance issue for me. If I slip that little belt I can lug the generator not having the proper voltage and damage the slip rings on that armature. I've had to replace the armature twice in it and it's not cheap. The parts of for it are no longer made and to trade out the generator I would have to do some major fabricating to accommodate another unit. If I stay with a V belt and increase the drive sizes to 5.95" and 4.25" it HAS to work as I can't be tearing up my impossible to replace generator. After exploring Poly Chains again I think I discovered I'd still have to use a sprocket that's wider than the belt since they're made to fit a wide range.

If you're up for it would you be willing to sort me out a setup? If so my current drive is 4.25" on a 1" shaft spinning 2550 to get me 3440 on the 3.15" driven end. I'd need to get as close to 3600 as possible. Then with that wide poly chain sprocket I'd maybe have to use a taper lock sheave since I don't have much crankshaft to grab.

How about trying an A belt, it don’t sound like you need to transfer much horsepower. Looks like sheaves might be deep enough, an A belt can wrap tighter than a B belt can.

true temper said:

How about trying an A belt, it don’t sound like you need to transfer much horsepower. Looks like sheaves might be deep enough, an A belt can wrap tighter than a B belt can.

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That's a great idea thank you! I really hope that would work and I'll be willing to try it. My BK sheaves should also run a AX belt fine I believe????

Sure wouldn’t cost much to try an A belt. For a low HP application I would give it a try. An A belt is quite a bit more flexible than a B belt.

Yeah those AX belts are cheap but I've been thinking about it since you mentioned it and wouldn't the belt speed get reduced since I'm lower in both sheaves. Both the drive and driven pulley speeds would slow right? I feel dumb needing to ask but I'm worried a tad about slowing that generator down even the slightest. Thanks again for you help, I appreciate it. The pulley calc is telling me if both drives are reduced equally (sitting lower in sheave) the smaller drive would speed up, is that right??