problem with chain drive

[pepa]

due to the size of the disk that the chain was attached to it worped slightly and caused the motor sprokets to jump track because of the small size of the chain. the salution was to find a chain that would allow for a little wabble in the plywood disk as it turned without the sprockets being put in a bind and jumping off the chain. this new chain and sprocket setup will allow for as much as a half inch without any problems. the chains and sprockets were part of a convoyer system for an old manure spreader

valt flying on test tower without motors

pepa.

[willib]

Hi pepa

i have another idea , on the insde of the flywheel of an 50 HP merc outboard , is a large gear . with teeth on the inside for where the starter motor turns the flywheel ... you get the idea?

you could use the flywheel and the starter gear and if you could find more than one starter motor , you could hook up as many of your generators as you wanted , that would fit, anyway.

[nothing to lose]

Sorry to see it broke so soon.

I wonder, since the drive system is under the unit, out of the rain, if a cogged belt and friction drive would work well for you. Use the belt same as you did the chain.

I mean like take a serpentine belt and bond it to the inside of the disk, then mount the pulleys on the motor, adjust tension for a tight fit so it doesn't slip.

Should not lose much power like using a belt normally because the belt would not be twisting and wrapping around anything like pullies, just running a straight circle and never bending.

The belt should last almost forever, no tension, no bending , etc...

Not sure if it would work well or not, just a thought.

[Norm]

If you would then work the pivot point right

so that it swings into the belt...the more the

load the harder it presses calculated to press

just enough tension to keep it from slipping....

              ( :>) Norm.

               

[electrondady1]

i still like the original chain drive method pepa.

'cause it looked alot like the stuff i've been saving. lol.

if the wooden disk could be kept from warping,

would it still be a viable power take off point?

i was thinking you were building a savonius mill

but those are darious type wings.

what sort of dimensions over all?

it's difficult to see what you have going there from you photo.

are they a lenz2 type profile?

[pepa]

hi Willib, very good idea, thanks, i would have to cut the center hole large enough to fit over the eight inch tower pole and it may not be large enough on this unit but would work on another one with different type of base mount. the larger chain may work as i can cut the sprocket thickness down to allow about one inch of up and down motion in the disk (half inch each way) and i am beefing up the plywood disk. i made this unit to slide over my existing 42' tiltup tower to raise the mill to about 45' level and i needed the large dia. center pipe. pepa

[pepa]

hello electrondady1, i am in uncharted territory with this one, i know nothing about the verticles but love to watch them turn almost as much as i like watching a water wheel. the wings are lenz want-a-bees and are 84" tall by 28" wide and mounted on airfoil shaped 2x6 treated pine struts. the rounded part of the wing was made by splitting a section of fiberglass pole in half and the wings are i/4" plywood. i made the wings so that they can bee moved in or out on the 60" struts to find the best position for rpm and tork for my wind area. i also have a set of winglets made to mount to the ends of the struts as soon as i locate the sweet spot and this will give me three three blades per side. i am looking for power through tork on this unit insted of speed. i had to tie the unit to a metal fince post while i was adjusting the bottom rollers and the wind on the wings were bending the top of the heavy gage post as it tried to rotate. i did not want my fingers between the guide rollers and the pole and we were having some nice little wind gust at the time. the unit turns very free and easy, pepa.

[willib]

Hi pepa , i dont know what i was thinking last night,the sprocket teeth on the flywheel are on the outside of the flywheel...

just wishfull thinking i suppose.

[pepa]

hi NTL, the belt would work, but for 24/7 operation it would ware a lot faster with all the stops and wind gust starts, than a chain would. if i had used a regular size bike chain with the thin sprockets it would have not been a problem because the difference in the tracking of the chain was only about 3/16" and when i mounted the support rollers to the motor bracket it was less than that. the problem was that the chain holes were very small with no room for any up/down movement. driving only one motor would probly work well with the belt, they are tough.

Norm, i used a double thickness of rubber intertube behind the motors to give a little resistance and to keep tention on the sprocket, thanks for the good sugestions everybody, pepa.

[thefinis]

Make sure the chain is facing the right way for the pressure direction. Those teeth will need some clearance behind the chain. You might could rout out an area behind each link hole once you get the circle and chain to match. I found that large wooden circles would warp over time when bolted to barrel halves no matter how well painted.

Another idea is that the chain does not need to be held except at points spaced close enough for support and power transfer but far enough apart and loose enough for the chain to have give. It may take a little deeper cut/higher shoulder because of the give.

This sure looks like a good candidate for a trailer hub with the correct sized rim and chain welded together. I wonder if a spring tensioner for the generator(gear to chain) would be a good or bad idea?

Finis

[pepa]

thanks for the ideas Finis, i thing i am on to something here with this design. yesterday, we had some good wind in short whirling gust as a front came through and i saw the flag constantly changing direction without the mill showing signs of any anything but strait wind direction. with the entire weight of the unit riding on one heavy bearing and guided by ballbearing rollers at the bottom it turns as free as a kids toy and will start to turn when the struts have to brush the bottom of the limp flag out of the way. i am planing to put this mill up into clean air but, i think this design will do well in a turblant wind area as well. keep the ideas coming and we can make it work (two heads are better than one) almost every thing that i build has been from ideas from this board, thanks to everyone for sharing. pepa

[alancorey]

Sorry to hear the chain in the routed slot isn't working out.  I had great hopes for it.  I guess keeping the alignment right isn't easy.

I wonder if VAWTs could borrow from something that came out of overshot waterwheels in their heyday: segmented gears.  On these they used a gear that was the diameter of the wheel, but it was made of interchangeable/replaceable segments.  These were probably made from cast steel that was machined for accuracy of the teeth.  Even if the gear was 50 feet or more in diameter, it wasn't much problem for the segments to be hauled (by horseback or whatever) into place and bolted in.  The wheel they bolted onto needed to be rigid, but Fitz was building steel wheels anyway.  It was a big step beyond wooden cogs.

These would be heavy, but they could be made lighter because we aren't dealing with hundreds of horsepower here.  I would think someone with a CNC plasma or laser cutter could make suitable ones out of 1/4 inch cold rolled plate.  The pinion gear that drives the motor could be fairly long, maybe a couple of inches, to allow for warping of the wheel causing it to not be all in the same plane.  The motor should be mounted on a spring arm that keeps it pressed against the gear to allow for eccentricities or out-of-roundness.  Modern materials might be lighter and cheaper than steel plate.

It's hard to believe that something that was in use 100 years ago can't be bought today, but any Googling I've done has come up with nothing currently in production.  Cheap fossil fuels and steam power were the end of waterpower, but now we need to rethink that.

I hope the manure spreader chain works out.  I thought that chain looked familiar.

  Alan

[pepa]

hi Allen, thanks for the information on the water wheels, i had forgot about the old segmenteded gears on those machines. i do love to watch the old water wheels make power and i think that we can do the same thing on a smaller scale with the vawts. this is my first effort with a verticle but i dought if it will be the last. i have the mill down now and am reworking the chain and also adding another layer of plywood disk for strength and to acomindate the wider chain. there seems to be plenty of room for up/down motion now and the guide rollers that i installed between bottom of chain track and motor brackets keeps rhe chain on a pretty even plan with the sprockets and also carries a little of the weight of the mill blades. i also changed out the inline skate wheels for much wider skate board wheels. pepa

[alancorey]

I was also wondering if rigging up wires and turnbuckles that work like spokes on a bicycle wheel would help.  You could tighten and loosen them as needed to true up the disk.  There'd probably be no end of keeping them adjusted though.  Bent pieces of all-thread going through angle brackets could be cheaper than all those turnbuckles, but you'd probably want locknuts.  Maybe the plywood will stop warping eventually.

  Alan

[pepa]

you figured it out Allen, i had cables running between the disks on the two sides of the s wing but the plywwod pulled the screws at the points of the s wing and stretched the screw holes a little. before it goes back up i will install cables at the points of the metal wings and that is where it warped the most. i will also add four extra cables between these four to have even support around the entire disk, thanks for the help, pepa.

[Norm]

Jerry uses a hard plastic composite material

for some of his hubs....it probably doesn't

warp? I don't know...maybe he can tell you.

                 ( :>) Norm

[thefinis]

Good luck with the wooden disks I always had trouble keeping them flat. In fact it was one of the reasons for junking my S rotors and turning them into yard art. Even when reduced to one layer with 3 barrel halves the 3/4" thick wooden disks warped.





Each layer would warp a little either where I bolted it or where it wasn't tied. I finally decided that it was going to take metal or plastic as building material for the disks. I never found a reasonably priced sub for wood even in my junk pile.

The design you are playing with is very close to a planetary gearbox design but without the sun gear in the middle.

http://en.wikipedia.org/wiki/Epicyclic_gearing

I have been studying planetary gearboxes lately because the big boys tend to use them to increase the rpms on the utility sized machines. Weight power ratio is very good and it tends to lend itself to either single generator design(runs off the sun gear) or multi generators (runs of the planetary gears).

I really think that you need evenly spaced sprockets to keep the alignment and pressure steady. 3 or more and they should help keep the bottom running true. A middle or sun gear on yours would be nice but really complicates the setup as it would have to spin on its own bearing.

If you are adding a second layer on the bottom have you considered attaching it with bolts and leaving a little slack so the layer with the chain can float up and down a little following the sprockets?

Finis

[pepa]

thanks for the tip Norm, the worped plywood problem was a combinition of different things and will be an easy fix in the future. the plywood that i used was a very good grade of maghony 3/4" inch that has been leaning against the wall in my shop for about eight years. i had 6 or 8 sheets of diferent thickness left from a big office cabinetry job i did and have been using it for different projects.

 i checked a couple of extra sheets after i had this problem and found that they all had a slight worp in the same place from being stored standing on edge insted of being flat. in other words i started out with a handicap and didn't catch it in the beginning. the biggy was using a chain that was the same size as the sprocket thickness with no room for error in the tracking around the speockets. the next time i will make sure that i have a flat disk and i think that using the old style wide link bike chain and the narrow ten speed sprocket will eleminate the problem along with making sure that the whole thing is well supported and braced. pepa.

[pepa]

hi Finis, did you ever get one to work for you? the four motor sprockets are the planet gears in this case and i set up the contact points by installing the sprockets on the motors and spacing the sprockets evenly around the chain and cutting the round motor support disks to fit around the motors and centered under the chain. bench testing proved that the sprockets ran true and easy in the chain as the motor support was rotated. the four sprockets did keep the wing running true after it was up on the test tower and i also added four skate boatd wheels to the chain disk that would roll on the support tower and the combination gave a very true guide for the chain orbit.

i will try again with the modifications to the plywood  and if it still gives me a problem i will find something else for the disk. thanks for the link and the ideas, i like the one about the floating chain disk and may try it because i dont give up easy, pepa.

 another IDEA??? suspose i screwed a series of lag bolts into the four layers of plywood and left about two inches of smooth bolt hanging down to be spaced for the large sprocket from the spreader chain to run on. that would give me a world of room for any play in the orbit. i could probably get Windstuff Ed to cut me a metal disk to size that i could weld studs to to make the annulus gear. it could be in several pieces and bolted to the plywood disk. what are your thoughts to that?

now we are rolling// suspose i use the same stud layout but with the studs a little further apart and then weld series of slip collars on the outside of a chain to slide on the studs for up/down movement, this way i could use any chain and sprocket system i want with the cheaper and lighter plywood with no problems of warping. add a little grease and get out of the way, pepa

[pepa]

finis, after i read the article on epicyclic gearing i memembered that is the way drill motors are geared. i actually made a windmill out of a 18v cordless drill motor and gear box. i used 40" pvc blades and it worked surprissingly good but it could not take the stress and gave up the goast after a few weeks. pepa.

[thefinis]

Four layers of plywood. How big are the circles you are cutting out? For some reason my mind keeps saying that the bolts hanging down would need something at the bottom to keep them from giving under heavy loading. Using the big toothed sprockets you could use studs/bolts spaced correctly instead of chain to get any amount of play you want but seems like a lot of work compared to using the chain but it is a very good idea. The part I like best is the chain being used as a gear and I hate to see it go as it is easy and fairly cheap. Not sure about having a plate or plates made yet until the rest of the design is firmed up. I think you are close to making something that works wish I knew which way to say try first.

I have been playing around with wings and supports. Have not made it to hooking up a genny yet. Never got a set of sail wings to work but it was more of a problem with the materials and the ability to stretch it tight without warping the frame. Ed's design has been the best I have had for a vawt so far and made so much torque my prony brake would not handle it. Right now I am waiting for time to build a tiltup tower so I can get one up into clean air.

I am going to try and use a final drive off of some farm equipment. One is off an old combine 6.5-1 it is pretty stiff but might loosen with fresh oil and being used. The other is 5.5-1 has a drum brake and spins easy but it hasn't been sitting as many years. They both take a 26"  8 hole rim which I hope will handle a 8' high turbine without using a top bearing. The one in the picture is 4' tall and tore up in a wind storm. Those foam wings(4x6 sheets) handled the wind 35mph+ even when pinned to a stop but the metal support and mounting brackets didn't. Did learn one thing don't pin one down to stop it unless what you pin it to can handle a lot of twisting force. LOL those form wings did not take the whole thing flying off the tower and crashing into the ground real well.

Finis

[pepa]

nice looking machine Finis, i hope it went back togather stronger after the crash. the main bottom disk is 36" od and the two layers under it are 36" od and 28" id where the chain fits for a total of 60" of chain. i was thinking of adding one more layer for extra strength, which would give me a bottom thickness of three inches to mount bolts to if i go that route. reguardless of how much bolt length is left at the bottom, the force of the sprocket will be against the top half inch below the wood and using grade H2 lag bolts, i think it would take a lot of pressire to bend or move one of those bolts. that was the main reason i thought about using a metal circle as a backing plate for the studs and i could increase the id for more reduction. if you were a little closer i would set you up with a fiberglass tiltup like mine. pepa.

[georgeodjungle]

i didn't use wood on mine.

still going...

[pepa]

hi George, any pictures of the vawt flying? i looked at your files and diary but didn't see it in the air, i probably missed it. i did see the barrol being cut. what type of generator? pepa

[DanOpto]

Try cogged timing belts

They are available in many sizes and strenghts to match various loads.

The chain drive wears quickly and also stretches over time.

They have a very high failure rate at high speed due to multiple moving connections.

Go to McCaster Carr and look up timing belts for a view of sizes

http://www.mcmaster.com/

[pepa]

hi danOpto, thinks for the tip on the chains and belts but in this case the chain is epoxied into a dado in the plywood and has no moving parts and cannot stretch with use. the chain acts as a fixed gear and drives the sprockets as the mill rotates. pepa

[Norm]

Cut the whole disk into pie shaped segments ...

up to the gear...and start the cuts on the

inner side of the outside edge .....plunge cuts

so as to form slots ....each piece cannot waarp

significantly by itself.....maybe ?

               ( :>) Norm.

 

[pepa]

Morm, you are good, the slots will help and i had not thought about that method. if the disk is attached only at the od the center will float slightly as Finis suggusted. the taper on the points of the sprockets will pull the chain up or down as they enter the chain holes and keep the chain in line with the sprockets. i can also wedge the sections into alignment to make up for the warp in the base disk.

let me run this idea by you. imagine a 1/4" thick x 1" wide metal band formed into a circle with the chain welded to the bottom id. a series of 5/16' id bushings welded around the od (about four inches) of the band and will be used to mount the band to the base with 1x4" lagg screws that are left with about 1/2" slack between bolt head and bushings. keep in mind that the base of the wings are held in line by a series of rollers that run on the pole in my case, or a bearing on another design. the chain can now be fit on the motor sprockets and raised to the base and lagged into place with a perfict alignment and the motor supports then secured to the pole. this method would eleminate the need of working to align the motor sprockets to the chain in a very tight space, also make the chain and sprockets into a real planetary gearbox. your valued thaughts folks please, thanks pepa.

[pepa]

i should have added that the motors support should be raised to to the center of play on the 1x4" bolts before it is attached to allow for any up/down movenent of the chain. pepa.

[Norm]

Sounds like a very good idea.....

BTW How about a ceramic disk? It wouldn't warp.

I didn't forget.....

http://www.fieldlines.com/story/2006/9/6/125446/0182

             ( :>) Norm.

[pepa]

only one drawback on that idea Norm, the disk is the same size as the od of my biggest kiln. would have to make it in smaller sections and bolt togather. pepa

[Norm]

Well aside from that it wouldn't warp....Oh well!

            ( :>)Norm.

[jmk]

 What if you bolted the plywood to a ten speed bicycle wheel to keep it true, or is the size wrong?