How to adapt motor to chain drive? Suggestions welcome!

[smaua]

Hi, I hope its okay to ask this, i tried looking on the wiki and forums and didn't find anything that answered my question.
Basically, I have a Kercher battery powered vacuum cleaner with a 25v motor which I've taken apart and want to try to make work on a folding bike.
I'm a bit confused as to how to modify the motor so that it can take a freewheel and chain..i`m just learning about all of this stuff so sorry if it's blindingly obvious.
Any suggestions are super welcome! I am happy to do things to it and take more pictures from different angles if that helps?

Thanks!!

In the image preview the pictures get cut off for some reason so i will put the direct links here as well:
http://s3.postimg.org/dic32k0cz/20151124_223056.jpg
http://s2.postimg.org/adzrghkll/20151124_223108.jpg
http://s21.postimg.org/3u10hh4mv/20151124_223134.jpg
http://s2.postimg.org/6cn9okhop/20151124_223148.jpg
http://s9.postimg.org/6vkczybbz/20151124_223157.jpg

So this is what it looks like.

 

[amberwolf]

A motor with that high an RPM is going to need a multiple-stage reduction. If you try to use it to drive the bike without that, at a power level sufficient to actually move the bike (especially with you on it) you'll probably burn it up in seconds (minutes at best), based on my early experiments with such things years back.


If you were to use a second identical motor as it's original designed RPM and voltage/etc, ducted to suck air thru the first, then it'd help to cool it off enough to last a little longer, but I don't know that it would survive long enough to be really worth all the stuff done to build it. (and it'd be really loud, especially if you have any filters on it to prevent sucking debris into the motors).


If you really want ot use that kind of motor, you should look up the various middrive builds based on high-RPM RC motors, which will be similar in capabilities and requirements to the vacuum-cleaner motor. There shoudl be numerous examples here in this subforum.


As for affixing a drive connection to that motor...before you worry about that, look up the stuff above and read around about motors, current limits, power, RPM, etc., in the various topics in the Sticky Index thread(s), to get an idea of the challenges you'll face and then you can decide if you still wanna tackle this motor for this project.


If not, then I'd recommend a much lower RPM type of motor (which will be larger and probably notably heavier for the same power output level), if you want a single-reduction (via sprocket/chain or pulley/belt), rather than multiple stages.

 

[smaua]

okay thanks a lot, i will read up more about the things u mentioned.
one quick thing though, would this problem be less of a problem if i just turn on the motor after i got a specific speed already? i guess it will still be hard to go uphill though? cause of the weight. but yeah ill try to understand things better. i am tryin to do this project for free and i got this hoover for free..so i don't think i could get another motor just like that.

 

[slowhands]

You are wasting your efforts. This motor needs to run very fast to develop much power and to turn its fan for cooling, like 2400 RPM. It will burn up quickly when used on a bike, at 60 RPM, unless you reduce the RPM by 25:1 using gears, and even then it may not last long. You need a motor with the gearing built in, and which is designed for sustained operation.

 

[amberwolf]

i am tryin to do this project for free and i got this hoover for free..so i don't think i could get another motor just like that.

You might have some fun reading my http://electricle.blogspot.com project blog from the beginning; I started out with not much more info than you have, and ended up with a usable bike eventually--though I run hubmotors now, I tried (and fried) a few motors and whatnot learning enough to get something really usable.