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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166
Posted: 01:36am 19 Oct 2011
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Govertical,
A correctly installed A section belt is rated at 7000 watts loading, I don't consider pairs or triples until the load is more than 10 horsepower. I cant tell what direction you are turning this from the photos but the tensioning idler must be on the unloaded side of the smaller pulley.
I would rather not state what I consider to be the bleeding obvious and sound like a prick But here goes!
Toothed belts ride up out of the slot when the slots on the little pulley wear, just like chain drives. If you cant keep a perfect edge on the pulley slots a timing belt will do the same thing as is happening now. You will need to use some stock with good wear characteristics and mill it perfectly to prevent this.
cheers yahoo
I'm confused, no wait... maybe I'm not...
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 02:45am 19 Oct 2011
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Hi, I agree with what your telling me. Suggestions and comments are always welcome. When I made the pulleys I rounded off the teeth to much. The weight of the mag rotors is about 20 pounds and there is a lot of force being applied to the teeth on the pulleys to start the mag rotors spinning. Using a wider belt and machining a better pulley to match the profile of the teeth on the belt should solve the problems. Thank you for all the suggestions.
just because your a GURU or forum administer does not mean your always correct :)
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 02:43pm 19 Oct 2011
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I wonder when the penny drops at your end regarding toothed Vee belts? A picture of a toothed Vee belt was shown further up the pages and I assume you are still playing with that one. Several people commented that this is a VEE BELT, not a toothed belt. Meaning, it should NOT run on a toothed pulley at all - you are barking up the wrong tree by persevering with that idea.
The correct groove angles and depths for all standard type Vee belts are on the net (just google vee belt pulley specs). Machine your pulleys for that groove and be done with it. It will work first time, promise Klaus
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 05:02pm 19 Oct 2011
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Hi, I pursuing the timing belt and grooved pulley approach because they are using the same technique to replace the chains on bicycles with timing belts. It offers very low bearing load and zero maintenance. I made some test pulleys out wood with larger teeth and a much better fit with the belt profile. I am very happy with the new test pulleys performance. I have gained valuable experience from the earlier attempt so it has not been a wasted effort. All comments have been very helpful, thank you. I am continuing with the modifications and I will post road test results when available. Thanks again and enjoy the day. just because your a GURU or forum administer does not mean your always correct :)
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 08:40am 01 Nov 2011
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Greetings, I finally found the correct timing belts. I had to make new pulleys. I purchased them for a auto parts store and the sales person told me they should be replaced every 60,000 miles The teeth are very large and the belts do not stretch. All the problems have been resolved and I do not for see any maintenance problems. Please disregard all earlier posts about timing belts. I am using a standard configuration for one direction operation. Enjoy the day.
just because your a GURU or forum administer does not mean your always correct :)
Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301
Posted: 12:51pm 02 Nov 2011
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Hi Govertcal,
The belt life at a minnimum should be 2,000 hrs at that rate!Did you keep the same 1:6.5 ratio with the new pulleys?Cheers Rastussee Rastus graduate advise generously
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 08:03pm 02 Nov 2011
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Hi, the teeth on the large pulley is 64 and the small is 24 with a belt tooth pitch of 3/8.
With about the same size pulleys it now has a 7: 1 ratio. I am not sure why but that is the way it worked out. I use a software program to generate the tooth pattern, it is low cost and works well. If you search for wooden gears you can find software. I am fabricating longer blade spokes so the blades will clear the offset belt drive. I will post road test result when available. Enjoy the day. just because your a GURU or forum administer does not mean your always correct :)
Air Bender Senior Member Joined: 25/01/2011 Location: AustraliaPosts: 206
Posted: 08:21am 03 Nov 2011
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Hi govertical,
That setup is looking good, it should spin easy.
Well done.
All the best Dean.
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 07:32pm 04 Nov 2011
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Results from todays road:
The inner set of blades are still to close and hit the transmission pulley.
I was able to do run the test using the just the outer blade. I noticed a improvement with the cut in voltage at a lower MPH. Shortly after cut in I heard a ratcheting sound of the belt jumping the teeth on the pulley caused from the movement of the idler pulley. I have to move the inner set of blades to a location where they will clear the pulley and improve the design of the idler pulley. Hope to road test again in the need future. Enjoy the day. just because your a GURU or forum administer does not mean your always correct :)
Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301
Posted: 12:34pm 05 Nov 2011
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Hi Govertical,
Is the idler problem due to it swinging in an arch?Cheers Rastussee Rastus graduate advise generously
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 01:35pm 05 Nov 2011
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Hi, yes that is what is happening. I mounted the idler on a straight post and it solved the problem. I still have to move the inner blade mounts out another inch and hopefully I can try another road test today. Enjoy the day.
just because your a GURU or forum administer does not mean your always correct :)
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 06:55pm 05 Nov 2011
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Greetings, results from today’s road test :
the idlers need to replace with a better design. The force the belt is placing on the idler’s is great and pushes them away from their ideal location. I am also taking the time to cut better cogged pulleys that will fit the belt pattern better. The results of today’s test indicates once the problems are solved with the idlers that larger blades or blades with scoops will be needed. Comments welcome.
just because your a GURU or forum administer does not mean your always correct :)
Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301
Posted: 11:39am 06 Nov 2011
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Hi Govertcal,
Once you have blade clearance there will be room to enlarge the top and bottom plates,on the idler pulley sides.If the claim that the belts won't stretch is reliable,you could bolt the idlers directly,at the ideal location.The solid location will not allow any movement and address the current condition.Cheers Rastussee Rastus graduate advise generously
yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166
Posted: 10:41pm 06 Nov 2011
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Goverical, it looks like an amazing piece of machinery!
if you are looking to timing belts on engines for inspiration there is a couple of things you could consider.
the idler has a good radius almost the diameter of a coke can to increase the belt life.
there are basically two types, one has a hydraulic damper and very limited movement and the other is spring loaded, purely to set/adjust the tension when it is fitted then the centre bolt locks it solid. i found this out the hard way and almost bent some valves when the belt jumped. Google image "timing belt tensioner" you will get the idea.
yahoo I'm confused, no wait... maybe I'm not...
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 05:10pm 10 Nov 2011
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Project update: Using a suggested method, I removed the idler pulleys and fabricated a u bolt mount to adjust the timing belt tension. It is very smooth and quiet. If the belt does not stretch there should be no maintenance required. Will post results of road test when available. Enjoy the day.
just because your a GURU or forum administer does not mean your always correct :)
Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301
Posted: 12:04pm 11 Nov 2011
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Hi Go Vertical,
Simplicity at it's best!As you've said "if the belts don't stretch"Cheers Rastussee Rastus graduate advise generously
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 09:38pm 12 Nov 2011
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Greetings, results from today’s road test:
at 5 MPH it started charging @ 0.5 amps. The belt again started skipping at a 2 amp output. I tighten the belt and started over. At 4 amps output the belt started skipping again. At that point the belt was so tight that it caused a increase load on the bearings and to me it did not make any sense to continue. I was expecting to see 8 to 9 amps @ 20 MPH because of the 7:1 ratio but only had a 4 amp output and the belt was still skipping. From today’s test results I am concluding that auto timing belts at such a high geared ratio can not handle the forces being produced and the current blade configuration started to stall at a 2 amp output caused from the accumulative load of the belt drive and the PMA. The current system looks good in the picture but does not perform well. It is a learning experience and a first attempt. I am fabricating new blades and reducing the ratio of the belt drive. Comments welcome.
Edited by govertical 2011-11-14just because your a GURU or forum administer does not mean your always correct :)
Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301
Posted: 10:50am 13 Nov 2011
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Hi Go Vertical,
To have a direct comparison,would you be willing to keep the ratio and blabes the same,and drive it with V belts and pulleys?If you consider the load to great,you could use dual belts to avoid slip.Cheers Rastus see Rastus graduate advise generously
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 01:17pm 13 Nov 2011
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Hi, thanks for the suggestions. I was able to exam my PMA and belt drive more closely after the road test and I found that the main shaft was flexing off center as I tighten the timing belts. This allowed the belt to walk over the teeth on the pulley. The more I tighten the belt the more the center shaft was pulled off center. I have to include another bearing above the bottom pulley to prevent the problem. I also believe that the small pulley is to small and not enough teeth on the belt are engaging the pulley. I did find out that my current blade configuration does need to be improve. I purchase some 6 inch pipe and I should be able to configure a C rotor style blade or J shape blade and do another road test in a few days. Thanks again and enjoy the day.
just because your a GURU or forum administer does not mean your always correct :)
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 02:55pm 13 Nov 2011
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Interesting results. I would not try a larger than 6:1 ratio with any belt type if the pulley sizes are to be kept manageable (sufficient No. off teeth to engage the belt on the smaller pulley).
Tell me, are those 2 x 7: 1 ratios? Do you really think your alternator needs a 7x7 (49) times increase in RPM? It seems to me that it may be wise at this stage to look at the alternator and ways to make it put out a suitable voltage at lower RPM.
BTW, Some time ago I built a similar alternator (triple rotor, about 150mm diameter) but gave up as at this small size it was just too hard to make coils with adequate turns for a sensible output voltage at a sensible RPM.
One could double the speed of the magnets passing the coils by doubling the diameter of the stator/rotor and get a much better efficiency than by doubling the RPM with extra gears.
Klaus
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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But here goes!
