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Post by 90GTVert on Nov 8, 2020 7:52:33 GMT -5
What size electric motor is required? We junk lots of 1/3>1 hp 115v 230v and 460v motors from retired commercial garage door operators. These come in flange mount and vertical base mount. If you need a larger motor I can ask around to the maintenance men I know to see what they have. What does the motor have to do? I’ll assume it doesn’t turn the dyno but somehow loads it during operation? It's gotta be really big. Here's the video so you can see his motor and it explains the DIY dyno. youtu.be/XUX_YWsECWs
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Post by captincvmn on Nov 8, 2020 8:29:17 GMT -5
Ok so he used a 147hp electric motor. I imagine when it was whole it probably weighed around 1000-1500lbs. I wasn’t prepared for that. But I see that the basic design just uses a weighted drum of known inertia to calculate power required to change its RPM. I have access to ample supplies of used 1-1/4” steel shafts with 1/4” keyway in them with bearings to match. There are larger sizes of shaft also, 1-1/2 and 2 with larger keyways. I wonder what I can find for a nice heavy perfectly round wheel to sit under the tire? I’ll have to think on this. I know the old Steam Engine guys used to use a large paddle fan as a dyno to apply load to a stationary engine. That wouldn’t tell you anything though. I’ll have to stew on this awhile.....
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Post by hippo008 on Nov 8, 2020 10:23:14 GMT -5
You don't need a motor at all. You can build a dyno with Hall-Effect sensors, a large counter-weight and RaspberryPi software that was already developed for DIY dyno usage. A user here named Pitobread has already done it.
Downside being you will need to find a large very heavy counterweight and probably learn some Python. The roller Brent pictured I dont think will work well. It didn't seem very concentric and it had a very large diameter. The frame to support it would have to be huge.
As for your belt busting problems Brent, I do wonder if thats just the nature of your system at this point. You are running a CVT system with a lot of range and a high horsepower setup. To me that sounds like a recipe for snappin' belts if there ever was one. I'd be interested to see how long a new Kevlar belt lasts if you swap in stock or close to stock CVT components.
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Post by 90GTVert on Nov 8, 2020 10:46:04 GMT -5
As for your belt busting problems Brent, I do wonder if thats just the nature of your system at this point. You are running a CVT system with a lot of range and a high horsepower setup. To me that sounds like a recipe for snappin' belts if there ever was one. I'd be interested to see how long a new Kevlar belt lasts if you swap in stock or close to stock CVT components. That has been my opinion as well, especially because I'm 300lb, but I seem to be in the minority with that thinking. I get lots of comments about how everyone else gets 1000 miles at least from belts with 80-100MPH setups.
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Post by 90GTVert on Nov 8, 2020 11:20:08 GMT -5
I guess I'm gonna be doubly-dumb and try the belt busting again. I moved the shims from the drive boss to the outside. It was topping out just over 60MPH with the narrow belt and shimming. Maybe that will push the belt a little harder and (oh joy) make it snap at higher speed.
I modified the rear mount and now I have a camcorder mounted back there where the GoPro was rattled to it's end. It's a real tight shot, but the best I can do. It's the old camcorder that I don't use anymore aside from secondary shots on rare occasions. I don't have any great expectation that it will provide any video worth seeing or that the camera won't break or even fall off.
If I accomplish nothing else, I may ruin every camera that I own... aside from the G7 that I primarily film with in the garage that is definitely not getting mounted to the scoot.
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Post by hippo008 on Nov 8, 2020 11:53:39 GMT -5
As for your belt busting problems Brent, I do wonder if thats just the nature of your system at this point. You are running a CVT system with a lot of range and a high horsepower setup. To me that sounds like a recipe for snappin' belts if there ever was one. I'd be interested to see how long a new Kevlar belt lasts if you swap in stock or close to stock CVT components. That has been my opinion as well, especially because I'm 300lb, but I seem to be in the minority with that thinking. I get lots of comments about how everyone else gets 1000 miles at least from belts with 80-100MPH setups. Are you still using the poor man's CVT setup with the Morini rear pully? I'm wondering if the combination of that pully plus an aftermarket variator just pulls your belt in a funky way. In my mind somebody could have a 100MPH setup and it wouldn't matter unless they had similar pully movement to your setup. I think this is a problem of belt geometry + power and not power alone.
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Post by 90GTVert on Nov 8, 2020 13:02:35 GMT -5
That has been my opinion as well, especially because I'm 300lb, but I seem to be in the minority with that thinking. I get lots of comments about how everyone else gets 1000 miles at least from belts with 80-100MPH setups. Are you still using the poor man's CVT setup with the Morini rear pully? I'm wondering if the combination of that pully plus an aftermarket variator just pulls your belt in a funky way. In my mind somebody could have a 100MPH setup and it wouldn't matter unless they had similar pully movement to your setup. I think this is a problem of belt geometry + power and not power alone. It's the complete MHR overrange with aluminum rear pulley. I sent the larger rear pulleys to a past forum member for testing on a drag scoot and that's the last I ever heard of them. As mentioned earlier in the thread, I have modified the rear pulley because I didn't like it out of the box... but I didn't get tons of miles out of belts on a setup that made less power with the old stock steel Malossi OR pulleys either. I was chasing my tail scrutinizing the CVT years ago because I kept busting belts trying to ride to the beach. Eventually I just realized that I was kinda stuck with a couple hundred miles as the max range if I wanted to stay safe and beach rides at that point were all 150-250 miles in a day so I came to accept that I had to change belts before every long ride if I wanted to have a chance to make it all the way. I was mostly mentioning the 100MPH setups because when people tell me about a 100MPH kit that's not much different than what I have, it makes me question all data that they present. 25MPH is a lot to add on top of 75MPH. I also question mileage claims in general for racing type scoots. I feel like I ride a bit, but the mileage really doesn't rack up. If I weren't tracking my mileage on paper, I'd swear I've put way more than a couple of thousand miles on the TPR kits. I'm back from trying again. The belt is still in one piece. Now about 16.4-16.5mm. I've measured busted belts wider than that. Really thought I was gonna pop it this time. The camcorder lasted till about the end of the driveway and shutoff. Didn't expect this, but it killed the battery. Battery life was supposed to be 2h47min. It lasted a few minutes. I guess something rattled loose in there because the battery won't respond. I went a little faster, but not much. I got to a stop sign near my house and it stalled out. I could either put the CVT cover on and hope it starts easy or just push it a little more than 1/8 mile. I pushed it. So now I'm around 200-210 miles on this belt that's thinner than anything I'd ever leave on there if I checked, plus I've moved shims around, and it doesn't want to break when I try to break it. Is that just my luck or maybe heat is a factor since it's very cool with no cover vs even my pretty well ventilated cover? Have I got it all wrong about how the belt normally breaks? Not sure what's up. Not sure that I want to keep going.
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Post by 190mech on Nov 8, 2020 20:04:07 GMT -5
Do you have a CVT cover that could be sectioned so the rear pulley could be seen,but the outer bearing is still intact?I always thought the bazillion drag race launches at the car shows killed the belts,didnt know average road riding had low belt life..
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Post by jloi on Nov 8, 2020 21:57:58 GMT -5
is this a ridiculous idea for a drum for the dyno or does it have some merit - I got the idea from this video - youtu.be/nDDcFEeqEI4 idea - find an appropriate length barbell- I don't think the dumbbell rods/poles would be long enough - anyway , steel rod/pole that weights slide onto - weld or otherwise fix the steel weights onto the rod permanently, one at a time until you get the desired length for your drum - turn the weights on the lathe - or I guess a bigger lathe until they are balanced and not out of round ; I don't know but I would guess maybe 5lb weights would be about the right size diameter. I don't know if the work involved makes this practical or if weights can be welded together - somehow also, if you need it I can donate a Raspberry Pi if it will work in place of an Arduino - bought 3 yrs ago? don't really have a use for it . still in the box . then there's these but they're too expensive - they come in different sizes, weights. www.homedepot.com/p/Roberts-75-lb-Vinyl-and-Linoleum-Floor-Roller-with-Transport-Wheels-10-950/100376311
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Post by 90GTVert on Nov 8, 2020 23:50:04 GMT -5
Do you have a CVT cover that could be sectioned so the rear pulley could be seen,but the outer bearing is still intact?I always thought the bazillion drag race launches at the car shows killed the belts,didnt know average road riding had low belt life.. I've never had a belt fail during a takeoff, but I would think the same thing. Always happens at speed. Doesn't seem to happen if I'm just cruising around. I'm gonna go back and find a few vids of belt fails and make sure I'm not missing something with the conditions. I thought about the CVT cover to see if I could basically cut one out totally to just have the outer support, but it looked like enough work and I really thought I would just go out and bust a belt easily first time out.
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Post by 90GTVert on Nov 8, 2020 23:58:32 GMT -5
is this a ridiculous idea for a drum for the dyno or does it have some merit - I got the idea from this video - youtu.be/nDDcFEeqEI4 idea - find an appropriate length barbell- I don't think the dumbbell rods/poles would be long enough - anyway , steel rod/pole that weights slide onto - weld or otherwise fix the steel weights onto the rod permanently, one at a time until you get the desired length for your drum - turn the weights on the lathe - or I guess a bigger lathe until they are balanced and not out of round ; I don't know but I would guess maybe 5lb weights would be about the right size diameter. I don't know if the work involved makes this practical or if weights can be welded together - somehow also, if you need it I can donate a Raspberry Pi if it will work in place of an Arduino - bought 3 yrs ago? don't really have a use for it . still in the box . then there's these but they're too expensive - they come in different sizes, weights. www.homedepot.com/p/Roberts-75-lb-Vinyl-and-Linoleum-Floor-Roller-with-Transport-Wheels-10-950/100376311Maybe it could be a possibility, but I'd almost think I might as well take my chances with the lawn roller at that rate. Plus,if I have to get someone to weld and machine stuff, it would get really expensive. I can do 1/4" steel with the flux, but I don't think I should be welding huge stuff together and it's nowhere near mini-lathe territory. I'm just thinking that a 100lb chunk of metal spinning at 2,000RPM is not something that you want to take a lot of chances with.
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Post by 190mech on Nov 9, 2020 5:07:30 GMT -5
Its gotta be heat from friction in high gear,if the crank is doing 14,000 how fast is the TD pulley spinning??
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Post by jloi on Nov 9, 2020 6:42:59 GMT -5
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Post by oldgeek on Nov 9, 2020 7:18:34 GMT -5
I have a theory on the belt busting. Brent said it usually happens at speed just after letting off of the gas. So friction/heat like 190mech said along with the sudden slacking of the belt due to the variator opening back up quicker than the rear pulley can respond. The rear pulley, clutch, clutch bell and gearbox are still fully engaged and have plenty of inertia. The belt is low in the rear pulley and still gripped tight. The top side of the belt starts to form an "S" between the variator and the rear pulley due to the slack in the belt. The inertia of the rear pulley could be snapping the belt at the BOTTOM of the rear pulley as the slack gets taken back up quickly. Sorta like snapping a fishing line, 10lb test line can hold a 10lb fish no problem until the fish snatches it good one time. When Brent eventually gets a belt break on video, we will know a lot more. Be careful Brent!
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Post by 90GTVert on Nov 9, 2020 11:36:08 GMT -5
I went back and watched some clips of belts breaking. It looks like I was wrong on the conditions and it's happening when I'm in the throttle, not when I let out. I guess I have it stuck in my head that it's letting out because I haven't been at full top speed. Like the last time, I was doing about 70 and then slowed down and got back in it and it broke at a little over 60. Sometimes it has happened at 40-50MPH cruising or getting into the throttle a bit. I do have a vid of one breaking at 68MPH on an old setup, so I was about topped out and WOT.
That changes things to some degree, but not a whole lot because I have been holding it WOT a little and I've been in the gas hard so many times that it could have busted if it wanted to.
So now with 1 GoPro totally done, a camcorder battery disabled and my only other GoPro flashing randomly when charging like it has a loose connection... it will annoy me even more if I can't see this happen on video. I may put the other battery in the camcorder and see if the GoPro will record or not and try again. I won't be buying a new cam and mounting that or going to any extremes, but maybe what I have left can get it. I also thought about taking the rear wheel off and seeing if it will break on the stand. I don't know that it would get much heat in the belt or put the same stress on there not under load though and I don't want to just hold it WOT with no load. I think that's prob a no-go. I may see what old covers I have and how hard it looks to get something that may provide some support (concerned about the case more than the gearbox since one is a definite crash).
I may not be able to do it anyway right now. I think the pump is getting worse. The pipe was coated again and I could smell coolant in the garage. On the last ride it was getting a little hotter than normal. Nothing to be concerned about with a 141F max, but I don't want it to totally give up and spew coolant. I hope it's just in need of a rebuild with bearings and seals, but I'm not so sure the shaft itself hasn't worn. Didn't have shafts on the site I ordered the rebuild kit on, but I do see them elsewhere for probably $20-25 shipped. $50 pump, $30-40 in replacement parts... could be one of those things that makes about as much sense to replace the whole pump. I think this pump may last longer if I didn't have as much tension on the belt. Adding the rubber to the mount puts it over the edge of where I want it, so I may not worry about it. Could redo the whole bracket, but that sucks.
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