Make a generator?

Discussion in 'Electrical' started by whizzer48, Feb 22, 2010.

  1. whizzer48

    whizzer48 Member

  2. GearNut

    GearNut Active Member

    They are very powerful motors for sure. I bet that some of them could make for a good generator, and most all are rebuildable for longer life. I don't know diddly about the 3-phase ones though.
  3. AussieSteve

    AussieSteve Active Member

    I'm in the middle of doing a similar thing, using a 120W 12V DC motor driven from my shift-kit jackshaft.

    ... Steve
  4. Fabian

    Fabian Well-Known Member

    Hi Steve,

    Can't wait for your photos of an electric motor connected to the jackshaft.

    Have you got any pics to tease us with?

  5. AussieSteve

    AussieSteve Active Member

    There's nothing much to photograph yet. I only got started tonight. I've been too busy tuning and riding for a few days.
    I got as far as working out how to mount the motor, (hereafter called a generator), probably just above the jackshaft, it fits like a glove and the approximate gearing to start with, about 8:1 or 10:1. That's just doable in the space. (At 10:1, the generator will be spinning at 1.4 times the speed of the motor. Might be too fast yet. At 7000 engine rpm, the genny will be spinning at 9800RPM. Trial and error will get things right.)
    Incidentally, this method has one drawback - it will only generate when the bike is moving. ie The clutch must be engaged to turn the jackshaft, so the battery must carry the lights while the bike is stationary. Not much of a problem.
    The generator is small but gutsy, as a motor it uses about 120W under load, (10A @ 12V). It came from a 12V portable compressor for pumping up car tyres.
    It's 57mm x 36mm, with a 3mm shaft that has a flat spot for a grub-screw.
    Should go close to doing the job.
    For now, at least, I'm setting up with plastic pulleys and a belt, but I'll have to get metal pulleys if it works OK. I'll probably mount the drive pulley on the side of the 17T sprocket, or hard up against it.

    I haven't thought about the regulator yet, but that bit will be easy. I want to ensure that I can get usable power first.

    Pic of the motor below.

    ... Steve


    Attached Files:

    Last edited: Feb 23, 2010
  6. Fabian

    Fabian Well-Known Member

    I've been thinking about this power generation issue for ages now - keeps going around and around inside my head.

    A good portion of the problem is packaging and power generation when the clutch is pulled in.

    What really needs to happen is for the generator shaft to use a 20 tooth helical cut gear that's the same as the crankshaft gear..
    Idle speed is approx 2000 rpm and would generate sufficient power to run lights and when revving the engine, a regulator would solve all problems.

    The generator could somehow sit under the carburettor and be plumbed into the clutch ring gear.

    I would love to have a crack at making it work, but don't have the necessary workshop machinery to do the job.

  7. AussieSteve

    AussieSteve Active Member

    Yeah, that's why I'm going the way that I am - lack of equipment, $$$$$$ and motivation to build something decent like that, especially since my thread generated 0 replies the other day so there would probably be no customers.

    Still, this type of system needs a battery to function well, otherwise everything stops working when the engine stalls and there'd be something wrong if the battery couldn't run the lights for a short time without generator input.
    ie A 12V 7Ah battery could run a 60W headlight for an hour or more. (Not that we need 60W of light.)

    It's nice to think about a specially-made helical-cut drive gear, but it's not practicable.

    I'm just making a 1-off now, for myself, so cost must be minimal. This is cheap, easy to set up and will work well once it's geared right and regulated, even if I have to change to a slightly different generator.

    I just copied and pasted most of this into my original thread, HT Motor + Shift Kit + 6V/12V generator .

    ... Steve
    Last edited: Feb 23, 2010
  8. machiasmort

    machiasmort Active Member

    Make sure you do what I did....

    In wondering what RPM, I'd get usable power at, I held a dc motor in my hand along w/ a power meter... In the other(here's the clever part), I held a dremel w/ the chuck attached directly to the motor.

    Moral of the story, the motor blew to shreds in my hand. Parts of the can stuck in the cieling tile... I got real lucky! Never hold a motor in your hand!!!

    P.S. It was numb for days!!!
  9. ibdennyak

    ibdennyak Guest

    geez Marty, a dremel????spinning at 20-30K???? You're lucky we aren't reading about you in the memorium thread. :icon_cry:
  10. machiasmort

    machiasmort Active Member

    Live and learn Bro, RC would be crackin up! I started slow but with all the stuff in my hands, my thumb slipped on the dremel throttle. The whole cage came unglued... Funny part is, I thought that was supposed to be the strong part??? I had glasses on! LOL!!!

    Don't do it MANG!