Light, fastest, climbs mountains, and pretty efficient

[flecc]

Yes, there's a shifter involved John, changing between gears up or down, but you don't need to bother with that to understand the gears. Just look at this extract from my above post again and you'll see that I've said how the wheel is connected:

"Now if that annulus around the outside is rotated (by a drive from the sprocket) around the whole, the planets are forced to rotate, since they are engaged with the stationary sun, and have to roll around it.

As those planets revolve around the sun, they and the ring cage they are mounted on are trailing along after the outer annulus as it turns.

As that planet ring is travelling slower, we connect it to the wheel, so the bike wheel is now revolving slower than the sprocket. Therefore it's geared down, so that's low gear."

That coupling of the selected gear and the wheel is done by an actuator either by the rider or automatically as the spin speed rises, but as said, don't bother with such details, it's only necessary to understand how gearing changes turn speed either up or down.
.

 

[flecc]

Just had an idea - and it will probably remain so....... but:

Supposing one had opposing overunning bearings on the carrier and the planets and that with the sun as the driver you had a negative gear ratio for low gear. For the high gear (direct drive) you would reverse the direction of the motor - the planets would lock and the carrier would be free to move - everything would move at motor speed.

Think I'll go and lie down for a bit before thinking this through again...

I's briefly considered this sort of method but dropped it immediately Miles. To keep a silent drive I'd want nylon gears still, and this locking method would put all drive force across a set of stationary nylon teeth. I feel that could lead to mechanical failure. As it is, to protect the nylon gears during changes I'd incorporate a neoprene or similar material "cush" hub, probably within the sun pinion, since that would be quite a large diameter for a suitable not too low ratio.
.

 

[Miles]

Yes, not too practical with nylon gears..

Bypass the planets with a freewheel from the carrier to the ring?

Too tired to think.... I'm off to bed....

 

[flecc]

Yes, could do, though I was considering a conventional motor to sun freewheel. The final details could be fine tuned in various ways, but I think the end designer could determine what they'd use.

It would be good to think someone would produce a motor of this type, but I won't hold my breath.

Re: tired. My world is opposite to most, my best work and concentration in the late hours. In the morning I can just about think up a coffee!
.

 

[Miles]

It's quite a lot of trouble to produce something which only has a marginal advantage (from a commercial viewpoint), unless you're designing for offroad ;-) use....


I'm at my peak at 9am after getting up at 6am and having had at least 2 coffees.....

 

[flecc]

I've long given up bothering much with the commercial aspects. The world can have what it chooses to want, irrelevant to me either way since I want no commercial involvement.
.

 

[Miles]

My position also.

 

[Miles]

I can't remember if I've posted these here before, or not...

Change-over Gear

Anyway, worth reviewing in the context of this thread.

 

[flecc]

You did post it before, but it was a long time ago now, so worth inclusion here as you say Miles. This sort of changeover would have been even easier for Heinzmann to incorporate with their single cog and annulus design.

I prefer the simplicity of mine though, using virtually what's there in most of today's hub motors.
.

 

[kraeuterbutter]

Have not read the entiere Thread yet...

but two things came to my mind after reading the first postings..

1.) (light <-> 2 motors):
instead of 2 motors, it should be possible to use one motor (brushless)
and use the triangle and star-configuration (or do you call it asterix !?!)

how ever: the problem would not be the motor (nearly every brushless motor should be usable for this when the windings are made for it, so rewinded)

there would be the need of a intelligent controller..
the difference between triangle/star is about factor 1.7

so: when the bike runs 10mph with star-configuration it would have the torque you need, when switching to triangle the speed of the motor would go up by factor 1.7, so it would run 17mph on same voltage..

ideally the controller should do this by itselfs..
so when you start it runs always in star-configuration, reaching maximum speed (and measured current not to high) the controller should switch to triangle configuration and the bike would accelerate even further..
when the current goes up too high (hill) and speed for that down, the controller should shift back to star-configuration

ideally the user should not feel anything about this..
it would simply be like having two motors, one winded for running 17mph max, one winded for running 10mph max.

thats for the motors.. this should cost only some few gramms of weight for additional wires and maybe a little bigger controller

-------------

second:
i slimm hub-motor, mounted between front and rear-wheel under the frame (with special build frame for that, maybe a little longer than usually)
would be a nice sollution i think..
the hub-motor would run slow and for that very quiet (as used from this kind of motors in the wheels)
you could use all the gears of the bike..
the one single additional chain should not increase noise that much..
weight-distributation should also be good, when the motor sits in the middle and not in front or rear-wheel

combined with a 14gear-rollof hub-gear that should be killer..
wide range of gearing -> should allow hill-climbe of any hill around with 6mph and nevertheless high speed in flat surfaces..

i mean it like this bike here,
picture:

but instead of that load motor a much more quiet hub-motor
(and because it does not have to carry the weight of the bike and the person on the bike like a spoked in inwheel-hub-motor, this motor could be build much lighter for same power as well)

free-running-units for the pedals: the bike on the picture above (more pics: http://www.pedelecs.co.uk/forum/electric-bicycles/263-first-offroad-e-bike.html)
uses such free-spinning units, so this is also no problem

 

[flecc]

It can certainly be done that way kraeuterbutter, and as you say a hub motor type would be quieter. However, I'm very definitely not in favour of using cycle gears for motor drive, hence my two speed hub suggestion.

Riders need lots of gears, motors definitely don't, especially if Hall effect motors.

It's illogical to use the cycle gears, since that gives loss of motor drive during cyclist gear changes, therefore losing momentum. This is especially important if changing gear when climbing, since the loss of momentum can be large then.

As you know, I'm opposed to electrical methods of changing motor characteristics such as in star formation, they are never as efficient as a motor using a best single mode design. I know you disagree.
.

 

[kraeuterbutter]

hmm.. shifting on a hill when motor runs through gears..
never thought about that..
could realy be tricky or a problem if the hill is steep and the load on the chain big.. unloading with motor maybe not that easy like when you pedal by yourself, where you can give it a "kick" and then reduce power as much so you can shift..

for your last sentence:
in rc-plane-sport there were long-time-flying-competitions..
there were - beside to "glockenancker-Motoren" also brushless-motors used..
AND: for getting most efficience out of them at two rpms: with a - mechanically switched - triangle/star-configuration !

same thing i have seen on a competition solar-powered one-person-car for a solar-ralley..
build by some German university..
it had also an hub-motor with incredible high efficience above 98% !!
AND: it used both, triangle and star-configuration, shiftable...

so: in both cases efficience is the thing most wanted... in both cases they used both..
there is no real change on the motor needed:
only - instead of connecting the 3 wires for star-configuration inside the motor or paralleling each two cables for triangle, you have to bring all 6 cables out of the motor and do the triangle/star-thing outside of the motor mechanically or idealy bring all 6 cables to the controller and he does it himself..

running a motor in triangle which is made for 17mph with reduced throttle at 10mph would never be as efficience than running the same motor in star for the 10mph and in triangle for the 17mph..

 

[flecc]

same thing i have seen on a competition solar-powered one-person-car for a solar-ralley..
build by some German university..
it had also an hub-motor with incredible high efficience above 98% !!
AND: it used both, triangle and star-configuration, shiftable...

This is what makes me so cynical about such claims kraeuterbutter, 98% efficiency in an electric motor is completely impossible and has never been approached.

Once I see that sort of statement from any organisation I know that I can't trust anything they say.

And as I so often say, if it were so easy, it would be on the market. The commercial world is never slow to exploit an opportunity.
.

 

[Ian]

I have to agree with Flecc, 98% efficiency is simply not a credible claim, it's only 3% short of perpetual motion A claim of even 88% for a small motor would make me sceptical.

 

[Miles]

Solar Powered Electric Vehicles

Obviously, it's not commercially viable......

Also, scroll down here:
Here are two electric trikes I have developed:


Alternatively, you could use the Cyclone motor without its gearbox, as it's 97.6% efficient...

 

[flecc]

Do you believe they are getting 3.6 kW power output, the motor sourced from one of those solar arrays Miles?

It's difficult to believe, even in Australian sunshine, and I definitely don't believe the 98%.

Just saw your Cyclone comment, and that motor sprung to mind when I read kraeuterbutter's post!
.

 

[Miles]

It does seem pretty unlikely, but I haven't a clue about solar panels.

As for 98%, I'd rather put my money on this than the Cyclone... Peak efficiencies above 95% are possible, I think, especially with larger motors, but usually at great cost and complexity... I can't see it being worth it for our type of application....

 

[flecc]

As for 98%, I'd rather put my money on this than the Cyclone...

Yes that's for certain.

I could believe around 95% for a specialised lab developed motor with very limited practical application, but I think 98% is pushing the credibility limits too far. These figures so often get loaded to give the most impressive result, and that's particularly true of organisations that need to justify funding. Some make advertising agents look like amateurs!

I think motors flexible enough for most practical uses are unlikely to touch 90% at present.
.

 

[Miles]

You're probably right, flecc. I posted it as it's often referred to but I really don't have any special knowledge or interest. Like you, I'm really more interested in getting the most out of what is immediately to hand...

 

[Miles]

second:
i slimm hub-motor, mounted between front and rear-wheel under the frame (with special build frame for that, maybe a little longer than usually)
would be a nice sollution i think..

This is pretty much what the Stokemonkey is like:
Cleverchimp: Stokemonkey: Overview