Friction drive outrunner setup. New DJ bike.
- Thread starter EVTodd
- Start date
oofnik said:
Thanks oofnik. I have been following your build as well. I see we're using the same controller too... And we're both from Illinois!
One of my first tasks is to make sure everything on this TowerPro motor stays together. I may change the bearings and have been thinking about running a bead of some kind of high temperature epoxy around the outside of the magnets and in between them. Does anyone know of a good brand (that you can get in a hardware store) that would work for this? Also. Will adding epoxy mess up the balance of the motor? While I'm at it should I coat all the windings with a thin layer of epoxy too?
A quick question for the outrunner experts out there. I ended up getting a 9t motor instead of the 10t (returning it would be a pain and I see the 10t version is out of stock). Is there much of a difference between the two? I know a 10t would have a bit more torque at lower rpms but is there anything major other than that?
recumpence
1 GW
You will get higher RPM and a bit better efficiency. 
So, Todd, how goes it? Glad to see another friction drive being built.
You should come by some time and we will go riding.
Matt
So, Todd, how goes it? Glad to see another friction drive being built.
You should come by some time and we will go riding.
Matt
etard
100 kW
Nice Todd, it looks like you are gearing up for an upgrade from the Kolmorgan. Your last mount was spot on, I can't wait to see this one. I gave up on mine in favor of rear wheel traction. I will be starting a build thread too. It's funny, I have almost everything in that picture, except for a slightly different motor, and what, is that a servo tester? Are you gonna break the packs down?
Hey, maybe you guys in IL can put together monthly rides, like they do here in SoCal.
Hey, maybe you guys in IL can put together monthly rides, like they do here in SoCal.
liveforphysics
100 TW
Make sure you have external bearing support for that friction drive shaft. That's a pretty small diameter friction roller too. Keep that tire dry, or you will hear a pop a bit sooner than you wanted.
Jeremy Harris
100 MW
liveforphysics said:
I'd wholeheartedly support that. Also, the bearings in that Towerpro are rubbish - when I striupped one of my 5330-10t motors I found that the bearings didn't even have any lubricant in them! They were also partially filled with exposy glue from when the motor was assembled.
Jeremy
liveforphysics said:
The shaft on the roller will have bearings on both sides so there's no load on the outrunner at all.
I will indeed keep the tire dry. I know friction drive stinks in the wet. I'm not too worried about popping a tire though. I have well over 1000 miles on my current friction drive setup and there's been no tire wear. This setup will have more power and a smaller roller but I'm going to use a beach cruiser style tire on the back this time. It would take a LOT of slipping to get through it.
I'm planning on looking for some high temp epoxy for the magnets today. Does anyone have any tips or think I'll screw the motor up by pre-gluing them?
I would recommend changing out the bearings as well, in addition to gluing the magnets in better with some CA glue.
I got my bearings from vxb.com. I don't remember the sizes off hand but there are two smaller ones and one large one. The stator is quite difficult to push out from the plate, but everything else is relatively easy to do.
I got my bearings from vxb.com. I don't remember the sizes off hand but there are two smaller ones and one large one. The stator is quite difficult to push out from the plate, but everything else is relatively easy to do.
oofnik said:
CA glue is like super glue, right? I've been reading around the net a bit trying to figure out which glue to use and there seems to be some debate on which kind (ca, or epoxy). My theory is that some sort of high temperature epoxy would be good to use in between the spaces of the magnets since epoxy is thick. Has anyone on here done that?
Ok... I found a web site that talks about using epoxy mixed with micro bubbles around the magnets. Are micro bubbles sold at normal hobby shops and is it really necessary? I guess my biggest concern right now is having the motor out of balance if the epoxy is uneven. I suppose the micro bubbles would help since they would make the epoxy lighter. Is the balance of the motor something I should even worry about?
Hi evtodd,
I remember reading about some other friction drive user that swears by them.
I am interested in what glue to use also. I see some folks are having magnet troubles on the motor I have purchased also.
Cyanoacrylate is nice cause it is just so thin it will run down in any gaps that didn't fill when they epoxied but I am a newb so I don't know.
The micro bubbles in epoxy are just to keep the weight down and I don't think it will make any difference to an ebiker.
Looking forward to seeing the performance numbers.
Joe
I remember reading about some other friction drive user that swears by them.
I am interested in what glue to use also. I see some folks are having magnet troubles on the motor I have purchased also.
Cyanoacrylate is nice cause it is just so thin it will run down in any gaps that didn't fill when they epoxied but I am a newb so I don't know.
The micro bubbles in epoxy are just to keep the weight down and I don't think it will make any difference to an ebiker.
Looking forward to seeing the performance numbers.
Joe
From the CA wiki http://en.wikipedia.org/wiki/Cyanoacrylate
Cyanoacrylate glue has a low shearing strength, which has also led to its use as a temporary adhesive in cases where the piece can easily be sheared off at a later time. Common examples include mounting a workpiece to a sacrificial glue block on a lathe and also tightening pins and bolts.
I found it totally interesting that you can use baking soda as a filler with CA.
Do motor magnets experience shear force?
[edit to add link}
Cyanoacrylate glue has a low shearing strength, which has also led to its use as a temporary adhesive in cases where the piece can easily be sheared off at a later time. Common examples include mounting a workpiece to a sacrificial glue block on a lathe and also tightening pins and bolts.
I found it totally interesting that you can use baking soda as a filler with CA.
Do motor magnets experience shear force?
[edit to add link}
Joepostal said:
That's what I thought but my concern with using straight epoxy was the weight and making the motor unbalanced.
Oh, and I may have been the person swearing by friction drive. I love it and seem to be the only one on this forum using it.
Everyone else thinks you'll pop a tire within the first mile. :lol: just kidding... sorta.I am not sure if there is any concern for imbalance since the glue should be on the non moving part but I am a newb so what ever you decide to try it will certainly help others when this glue issue has been sorted out.
I wouldn't doubt it was you I was reading about friction drives. Not many folks want to try them although it is a dang simple solution.
I wouldn't doubt it was you I was reading about friction drives. Not many folks want to try them although it is a dang simple solution.
Joepostal said:
Actually, the magnets are on the part that spins so balance may be an issue. I'm hoping to find some high temperature epoxy within the next day or so and try it out. At least it's a cheap motor. I just don't feel like waiting for another one from China if I screw it up.
Does anyone know what kind of temperatures I can expect the outrunner to get up to during normal to heavy use? I've found some off the shelf 5 and 10 minute epoxies that can withstand well over 200 degrees f. I know some go higher but I haven't looked around too much yet.
Has anyone powered their servo tester using a small battery pack instead of a bec to draw power from their main battery?
This is the servo tester I currently have (I know, I'm cheap):
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8373
I was thinking about powering it using one of these filled with rechargeable nimh batteries:
http://www.radioshack.com/product/index.jsp?productId=2062254
Would 4 AAA batteries last long enough for a normal ride or two? Like I said, I'm cheap and $1.99 (plus the batteries) seems a lot better than the prices I've seen for a high voltage bec.
This is the servo tester I currently have (I know, I'm cheap):
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8373
I was thinking about powering it using one of these filled with rechargeable nimh batteries:
http://www.radioshack.com/product/index.jsp?productId=2062254
Would 4 AAA batteries last long enough for a normal ride or two? Like I said, I'm cheap and $1.99 (plus the batteries) seems a lot better than the prices I've seen for a high voltage bec.
drewjet
10 kW
I use JB weld for gluing in magnets. Super strong and high temp resistant. It does have steel in it, but so far no adverse effects. It is kinda a a pain to glue it up, as the magnets move it around as you glue.
I use a 3 cell lipo 700 MAH and BEC ( Ihad them on hand) and I get a lot of rides out of it prior to neding a recharge, the draw is very low. 4 AAA bats should work just fine(It is what they were designed to work on).
I use a 3 cell lipo 700 MAH and BEC ( Ihad them on hand) and I get a lot of rides out of it prior to neding a recharge, the draw is very low. 4 AAA bats should work just fine(It is what they were designed to work on).
Well, my plan was to have most of the project done this weekend but I'm still waiting on parts... Mainly bearings for the mount. I assumed I could get .5" id bearings locally. One place had them but wanted $40 each! Yikes! Thank goodness for the internet.
I decided to hook everything up and at least see the motor running before I tore it apart to add glue to the magnets (I think I'm going to go ahead and try epoxy btw). I'm surprised by how quiet it is. I only tried it at 12 volts but I like the way it sounds so far. I guess video cameras really do amplify the noise from motors.
Yikes! Thank goodness for the internet.I decided to hook everything up and at least see the motor running before I tore it apart to add glue to the magnets (I think I'm going to go ahead and try epoxy btw). I'm surprised by how quiet it is. I only tried it at 12 volts but I like the way it sounds so far. I guess video cameras really do amplify the noise from motors.
I finally have the drive pretty much done so I thought I would post a pic of the mount and roller by itself. I still need to fancy it up a bit, round all the corners off, and let it run in my vibratory tumbler to deburr and remover the cutter marks, etc...
The top plate is to stiffen the small channel aluminum I used. I also made bearing covers to keep anything from moving around. I'll post more pics as I get all the little details worked out.
The top plate is to stiffen the small channel aluminum I used. I also made bearing covers to keep anything from moving around. I'll post more pics as I get all the little details worked out.
Grinhill
10 kW
Nice work Todd.
I like the sound of a "vibratory tumbler". What does it have in it, sand or ball bearings or something else?
How are you going to attach the motor shaft to the roller shaft? Did you get the roller shaft bored out?
I like the sound of a "vibratory tumbler". What does it have in it, sand or ball bearings or something else?
How are you going to attach the motor shaft to the roller shaft? Did you get the roller shaft bored out?
Grinhill said:
There are lots of different kinds of media people use in tumblers. I use a plastic/ceramic pellets with a water and soap wash to deburr parts then they go into a 2nd tub with walnut shell pellets and a polishing compound. If you leave them in that one long enough they come out looking like chrome.
The roller has a case hardened shaft with a hole machined through it the same size as the outrunner's shaft. Actually, I got lucky, the EV Warrior roller shaft already has this hole and it was the perfect size for my motor. I simply machine an undersized hole through the side of both of them and use a hardened split pin to hold them together.
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