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Forum Index : Off topic archive. : ExerCycle
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Gill Senior Member  Joined: 11/11/2006 Location: AustraliaPosts: 669 |
Got the exercise bike going yesterday. Here's a few pics: The Bike 
The modification 
The electrics 
The mounting 
The bike is a Repco _ Bionic Bike. I found it at the dump BuyBack Shop and on seeing the compound gearing, I pounced on it and bought it for $5. I think the pics make it clear on generally what was done. The stator currently fitted is 7poles in series, 3phase Delta, x 2 in parallel, not decogged. This gives just over 200v DC open circuit, and plateaus at a fraction over 10 Amps when connected to 12V battery. Cogging is not an issue though the degree of difficulty to pedal goes from medium to very hard then it drops back to just hard again. What I did not consider and was not expecting is the unrealistic riding feel. On a pushy we can back off on peddling and the momentum carries us on, so brief pauses are not a problem. But on the exercycle no energy is stored as momentum because we've made electrical energy instead. The slightest pause, however brief, is like applying the brakes. It is a cruel punishment indeed, demanding constant attention and inflicting severe consequences should you neglect them. I'm naming my bike "The Wife". Now that I have a feel for how this one runs, I'm thinking to run the following stator. 6 poles in series, 3 phase Delta, switching into parallel a further, 4 poles in series, 3 phase Delta, switching into parallel a further, 4 poles in series, 3 phase Delta. So that's a selectable 6 &/or 4 &/or 4. (When I've got nothing better to do.) (Posted here cause it's not Wind or Solar or Electrical but more 'miscellaneous other') Now with this posted it's off for another ride..... was working fine... til the smoke got out. Cheers Gill _Cairns, FNQ |
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| matt down south Regular Member  Joined: 20/10/2007 Location: AustraliaPosts: 50 |
hi gill on my bike i use 13.75 to 1 gearing with a 100 series stator with 2 poles in series and 1 pole all in star so out of all the 42 poles im just using 9 and it seems spot on for effit in verses power out.i hope this helps matt matt |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5036 |
I must say its an impressive looking beast. Maybe I should create a new section for stuff like this. Yep think I will, I love to see this sort of stuff on the forum. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Gill Senior Member Joined: 11/11/2006 Location: AustraliaPosts: 669 |
Thanks for your data Matt. I have a lower gearing at just under 11:1 and using S80 stator. I might follow your lead in part and go S100 too. I know KiwiJohn runs 7 Pole, 3 Phase, Star only but no idea of his gear ratio. I like the idea of being able to switch in BIG LOADS for a brief time as I'd get bored at a constant load. Because mine is really for exercise more so than power I'll wear myself out over a shorter time. If I were looking more to generate power I would have to go to a much lighter load for it to be sustainable. Lots of fun. was working fine... til the smoke got out. Cheers Gill _Cairns, FNQ |
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| matt down south Regular Member Joined: 20/10/2007 Location: AustraliaPosts: 50 |
hi gill yeah ive tried 80 and 60 combos but always end up putting back the 100 and its higher cut in speed,another thing ive tried is joining another two poles series in star for a harder push you could switch the added poles in with a 2/3 phrase mains meter board switch for power runs when the ads come on the box.the 100 stators work well in 24v mode also matt |
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GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
I am intending to modify a repco exercycle as well. I picked up a pacific scientific 1.6kW brushless servo motor. I will use the same MPPT cct as on my mill and add a pot to control the gain. The nice thing about the MPPT is the smooth loading. The setup cuts in at 6V gen output and this is like riding on the flat. As the cadence increases, the loading increases, like it does on a real bike. The pot control will give the sensation like riding up an incline. I have the intention of computer control, so a workout program will control the gain. This will be an ideal use for the picaxe chip. The system will hook up to the 24V battery as a load. Wouldn't want to waste the energy. cheers, Gordon. become more energy aware |
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| Gill Senior Member Joined: 11/11/2006 Location: AustraliaPosts: 669 |
Yes Matt, that seems like what I would need. I'm in no rush so will keep my eyes peeled at the buyback shop. Hay Gordon, great score. Is the stepper intended for the bike? I like the idea of a computer controlled workout. I had thought of something similar and that was to simulate each leg of the Tour de France, but thought "who would want to sit on a bike going nowhere for that long?" I don't think it would sell. But your idea might. For me, If I wasn't charging the batteries I wouldn't have enough incentive to get on the bike. Now it's a useful waste of energy. was working fine... til the smoke got out. Cheers Gill _Cairns, FNQ |
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| petanque don Senior Member Joined: 02/08/2006 Location: AustraliaPosts: 212 |
The sports physiologists suggest that an elite cyclist can maintain an output of about 400w a more average cyclist is capable of sustaining in the order of 200w. Would some sort of flywheel give a better and more natural feel to pedalling? |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Gill, The motor is a permanent magnet brushless servo motor, with samarium cobalt magnets. there is no cogging. Current and active shaft position encoding control the rotor position. I will only use it as a generator, connected to an exercycle. cheers, Gordon. become more energy aware |
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Art_ Newbie  Joined: 22/10/2007 Location: AustraliaPosts: 30 |
I've seen it suggested on another site to mount weights on the regular bicycle wheel to keep up the momentum. Not much use for this one since it has no wheel :D If not actually, then potentially. |
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| Gill Senior Member Joined: 11/11/2006 Location: AustraliaPosts: 669 |
Yes I think a flywheel may be just the ticket. Thanks. Though there is only one place I see where it could be easily mounted and that is onto the rotor. I wonder if a large steel disc there would interfere with magnetic fields?????? Anyone tried this before? was working fine... til the smoke got out. Cheers Gill _Cairns, FNQ |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
The gen has a closed magnetic field, so there would be no effect. cheers, Gordon. become more energy aware |
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feix62k Newbie Joined: 30/07/2008 Location: AustraliaPosts: 36 |
great pics gill love the exercycle I have 2 spare moters guess I will try one of these next what would you recomend for a rewire, just want to charge a couple of batteries for portable tv pc ect and keep a bit fit another great looking project thanks dont the days seem lank and long when nothing gos right and everthing gos wrong |
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| feix62k Newbie Joined: 30/07/2008 Location: AustraliaPosts: 36 |
dont the days seem lank and long when nothing gos right and everthing gos wrong |
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| Gill Senior Member Joined: 11/11/2006 Location: AustraliaPosts: 669 |
Funny you should comment on the exercycle as I've just started little(15min) rides again. OK! So I'm out of condition.  But have to make the start to get better.
There's been many configurations recommended. There could be several contributing factors that make the difference of what's best for you. All a bit of a guess really. I used a higher voltage stator I built for my micro hydro but never had to use it. It's 7 poles in series, 3 phase Delta, times 2 in parallel into a 12Volt battery. It's heavy to push when out of nick so I've backed off the rotor by 6mm for a medium loading. I've got a second Repco to convert but it doesn't have the arm exerciser, just a handlebar. Can only ride one at a time so not rushing to make a start. Need to wear the first one out first. Hay?! It's good fun but you'd need to be awfully dedicated to use it for charging anything important. I use it just as a supplement to the primary systems.  was working fine... til the smoke got out. Cheers Gill _Cairns, FNQ |
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