Ironless axial flux Halbach project - 170mm, 36 pole, 44mm bcd disc brake mounting

[madact]

This is why I've argued for off street racing classes to be defined in the reverse way to street laws. For racing you want equal power input levels and unequal output levels to give an advantage to people with higher efficiency. For the street the focus is on output without regard for how many losses occured to get there. Totally different mindset.

I like the concept - I guess it really depends whether a racing category corresponded to a 'street legal' class or not. If there's a licensing & registration category corresponding to a particular power output, it makes sense to have a 1:1 correspondence in the rules to get more participation - if not, the other way makes sense, if you want to make it a techy sport. Trouble is, techy sports usually aren't great spectator sports, unless everyone is funded up to the point they have a level playing field (like Formula 1)...

The other way to run it, to get a good blend of action and technical merit, would be to limit power output and (swappable) battery capacity, and set the time / distance limit such that a really efficient bike can get away with one less battery change... that does require the event organizers to supply the batteries, though, which is a big cost barrier...

Back on topic, I've had a play with OctaveFEMM, it's pretty nice - if a little slow to draw stuff, probably due to the file interface, I think. The way forward seems to be to draw the geometry as few times as required, and use the group select and move commands to vary the measurements. Simulation takes a while, of course, so it's the kind of thing to leave running overnight. The advantage of this approach is that I can do something similar to your spreadsheet, but use FEMM to calculate torque for various airgaps, stator core thickness etc. Octave has some very nice graphing capabilities, too.

 

[pedalless]

The laws alway deal with "output" power actually delivered and not "input" power introduced to the controller. So a 24 V 10 Amp controller might be allowing 240 watts of "input", but in most cases after losses in the motor you will have under 200 watts delivered to forward motion.

Recent e-bicycle laws went under review in Australia and it was proposed 250watt measured at the rear wheel as it is worded now the law states motor must not exceed 200watts.The review did nothing the law remains unchanged and is still 200watt unfortunately.

 

[madact]

Recent e-bicycle laws went under review in Australia and it was proposed 250watt measured at the rear wheel as it is worded now the law states motor must not exceed 200watts.The review did nothing the law remains unchanged and is still 200watt unfortunately.

Well that's just silly - there is no such thing as a 200W motor. It's a complete technical non-sequitur. Does that mean that if I buy a motor in a store, which is labelled "200W" and drive it at 500W (in an operating envelope which doesn't cook the coils) then that's completely legal? I doubt any court would agree with that interpretation...

Likewise, measuring "power input" is totally without merit - this would mean that the addition of some ballast resistors to a switching circuit would make a system illegal - by getting hot. Ridiculous much?

Or is that talking about measured power output "at the motor"? In the case of a hub motor, "at the motor" and "at the wheel" are synonymous...

The TransportSA publications say that a power assisted bicycle's motor must 'deliver' a maximum of 200W, not 'consume' 200W - if this is not measured 'at the wheel' for a hub motor, then where, pray tell, is it measured? Then again, if you take a close look at the wording there, I could technically be charged with a violation for carting one of my model plane or car motors, in it's retail pakaging, on my carrier rack (hobbyists beware! )...

Still, it's a real concern, I think I'll chase down the wording of the actual legislation.

 

[madact]

Well, the law is not too hard to find ("in Communist Russia..." etc.)

http://www.legislation.sa.gov.au/lz/c/a/motor vehicles act 1959/current/1959.53.un.pdf

"SOUTH AUSTRALIA

The Motor Vehicles Act 1959, defines a power assisted pedal cycle to be a pedal cycle with an auxillary power drive attatched up to a maximum of 200 Watts.

Part 2, Division 1, Section 9B, covers the exemption of registration for a power assisted pedal cycle.

OK... I don't see a Section 9B in there

Part 3, Division 1, Section 25, states that a licence is not needed for a power assisted pedal cycle.

Source: SA Motor Vehicles Act 1959.
"

Part 3 has no "Division 1", nor (by implication) a "Division 1, Section 25".

The Motor Vehicles Act no longer contains any mention of bicycles, powered or otherwise.

The actual restriction seems to have been moved to the dictionary of the Australian Road rules:
http://www.legislation.sa.gov.au/lz/c/r/australian road rules/current/1999.219.un.pdf

"bicycle means a vehicle with 2 or more wheels that is built to be propelled by human power
through a belt, chain or gears (whether or not it has an auxiliary motor), and:
(a) includes a pedicab, penny-farthing and tricycle; but
(b) does not include a wheelchair, wheeled recreational device, wheeled toy, or any
vehicle with an auxiliary motor capable of generating a power output over 200 watts
(whether or not the motor is operating)."

This phrase in particular is quite interesting: "an auxiliary motor capable of generating a power output over 200 watts". Clearly, the measured power is the power is at the motor, but with a hub motor, that effectively means 'at the wheel' anyway. "power output" means we can have a 20% efficient motor that draws a real 1kW from the batteries, and we're still in the clear (and toasty warm, to boot ). The interesting part of this is "capable of"- in theory, any of the motors sold as 'legal' can be made to deliver more than 200W - show me one that can't, and I'll tell you to go put your electric toothbrush back together and stop being silly.

The motor in this case has to be considered as battery + controller + motor, otherwise it is technically impossible to make a determination of whether it breaks the law, given that the law states a limit on power output - in watts. They can change the law, but they canna rewrite the laws of physics, capn'!

I'd be interested to know if this has ever been tested in court - pedalless, do you have any idea?

This brings up another interesting question - take this scenario:
- You have a motor and ESC can deliver 200W (and is labelled and marketed as such) with a 24V battery.
- Dropping in a 48V battery (which you don't actually own) would cause
(A) power output to reach ~400W without compromising actual reliability
AND (B) the manufacturer's published heat, current and power specifications to be exceeded, warranty voided etc.
- The cops pull you over while you're riding down the street on said bike, with no battery in it (as you have your 24V pack which came with the bike on charge at home).
Can they charge you with riding an unregistered motor vehicle? Do they need to prove you have a 48V battery pack, or do you need to show that you don't, or is it irrelevant because the motor is capable of 400W, or is that irrelevant because it isn't specified for 400W?

If anyone has some ideas on that last one, I'd like to know (maybe we should start a new thread in MotoredBiking Laws & Legislation).

 

[pedalless]

I'd be interested to know if this has ever been tested in court - pedalless, do you have any idea?

No sorry i don't. I did read about a case in i think the Australian
thread here that there was a rider of electric scooter with pedals
taken to court, they didn't prove the motor was over 200watt
so instead the prosecution argued the motor was primary
means of propulsion for the bike not an assist. They won and
the repercussions resulted in many businesses selling these electric
scooters with pedals going out of business. The defendent got
a big *** fine to.

In regards to measuring the output brake horsepower is measured at the rear wheel and obviously
gives the true power output after all the losses etc, if we want just the motor output it is and always
has been measured at the output shaft of the motor not the rear wheel. If you get a chance to see
inside the semi trailers that haul race bikes around alot have engine dynos onboard for testing the motors
before they are installed on the race bike. . I agree this is not optimal for electric motors that can be
over volted but this is how the law is, if you have 200watt sticker on your motor your good to go it seems haha

The USA and Canida is same but more power allowed here is section from Canadas e-bike law

"They are currently defined as a two or three wheeled bicycle with an attached electric motor of 500W or less and which is capable of being propelled manually." Not it specifically says motor of 500watt.

USA Law

"an electric motor of less than 750W "

Same thing but bigger limit

I think the law is inadequate myself but not much we can do
about it.


You should also join the Endless Sphere electric forum mate there is thousands of e-bike uesers there
that can help rather than the handful on this site which is more about the 2 stroke china motors i think.
THere is already several members their building their own design motors.

 

[madact]

In regards to measuring the output brake horsepower is measured at the rear wheel and obviously
gives the true power output after all the losses etc, if we want just the motor output it is and always
has been measured at the output shaft of the motor not the rear wheel. If you get a chance to see
inside the semi trailers that haul race bikes around alot have engine dynos onboard for testing the motors
before they are installed on the race bike. . I agree this is not optimal for electric motors that can be
over volted but this is how the law is, if you have 200watt sticker on your motor your good to go it seems haha

But surely, as I said, the shaft is the wheel in my case? The rotor bolts onto the disc brake mounting for Pete's sake. Or are we talking about with & without tyre rolling resistance / bearing friction?

You should also join the Endless Sphere electric forum mate there is thousands of e-bike uesers there
that can help rather than the handful on this site which is more about the 2 stroke china motors i think.
There is already several members their building their own design motors.

Sounds good, I will go check em out.

 

[safe]

I'm the only other guy in the world (to my knowledge) building a similiar Halbach Array motor for an ebike.

As for the motor laws... horsepower for cars is measured after losses too. When you talk of a 500 hp car motor that's because they hook it up to a dyno and measure what it can do. If you were to calculate the fuel going through the carburator and estimate it's theroretical horsepower you might be pushing 2000 hp worth of fuel in order to get 500 hp worth of output.

A lot of ebikers get the idea mixed up.

 

[pedalless]

A lot of ebikers get the idea mixed up.

From what i have read from you safe it appears your the one that is mixxed up. The law is clearly written and your also not 100% correct about cars horsepower measurements. Motors are dynoed safe and yes so are complete cars. BHP brake horse power is the term given when cars are dynoed on the rear wheels and is always writtend after the h.p figure, e.g 500BHP if it was measured at the crankshaft it would not have the BHP after it. I worked as a motorcycle mechanic for over 20 years Safe i maybe new to these ebikes but i have been in the automotive field all my life. I bet you didnt know that alot of the race teams have motor dynos onboard their mobile workshops they cart to the race meets? The motors are dynoed in the trailers before put into race bikes to check their output power.
Now how this is done with a hub motor i don't know but the law clearly states motor output not BHP or measurement at rear wheels as your saying safe. I can see why you would want it this way especially for this silly 1000watt racing idea of yours, if you stuck with the letter of the law you would be restricted to 750watt motor instead of the 1000watt you claim you can use because measuring is done on rear wheel, but as we have seen on the Arizona racing thread you don't listen to anyone and seems can't be told anything you don't want to hear, word of advice safe, continually saying its so doesn't make it so mate. Go read the laws your preach carefully says nothing about rear wheel measurement distinctly states motor output not rear wheel output, if it was as you say it would be written total out put power at as measured at the rear wheel (or something to that effect) as this was how the New Australian law that was discussed was worded. I have read on Endless Sphere similar discussion in my initial research and it is the agreed this is how it is, your the only one i have read that believes it is different :-|

My 500watt hub motor has 200watt stickers on it now so i will plead ignorant if questioned by police about it being to powerful haha. I was going to get the 49cc china motor but found when researching here they are ilegal in Australia so went for the more inconspicuous hub motor with fake sticker (go that idea from Endless Sphere thread hehe) so far no trouble with the law coming up to 1000km on my first bike now still miss the noise of the internal combustion engine though i admit, it is a nice change sometime though haha

Sorry to OP for getting a lil off topic here but i thought it important seeing your wishing to keep within the law. I wont enter into an argument with safe from what i have seen on this forum he just doesn't give up just goes on and on and on haha

Again best of luck with this motor build.

 

[madact]

Go read the laws your preach carefully says nothing about rear wheel measurement distinctly states motor output not rear wheel output, if it was as you say it would be written total out put power at as measured at the rear wheel (or something to that effect) as this was how the New Australian law that was discussed was worded.

I'm glad the new Aussie 250W law hasn't gone through, and I hope it doesn't. My motor is only useful at well over twice the speed at which that law would have made it illegal to run (25kph) - under 50kph it won't do much more than sit there and gently cook itself... well, you still get torque, but very little power, not really worth the battery discharge.

I'd be all for new legislation if it had something like this speed profile in it: max 500W up to 30kph, max 200W above 40kph, linear slope between 30 and 40. Dyno testing at the wheel is dead easy compared to testing at the motor - heck, if it were something reasonable like that, I'd build the dyno's for the cops myself at cost + 10%, and get 'em certified by the local university (it'd probably go to public tender, of course...) - it'd be <10kg of kit, cost similar (or less) money to a breathaliser or laser gun, and they could tote it in the trunk of a cruiser and do "random power testing" on ebikes they see on the road.

Mum'd be happy with a 500W hill-climber to make shopping easier (she gets nervous and doesn't like doing over 30kph anyway), I could have my high-efficiency (rural) highway assist, people could ride sensibly powered e-bikes and be in the clear, and the cops would know exactly what they had to enforce and have the tools to test it. Everybody'd be happy ('cept safe, of course, with his 1kW racer, but I don't see him moving into this jurisdiction any time soon). We just have to get the transport minister(s) to spring for it .

My 500watt hub motor has 200watt stickers on it now so i will plead ignorant if questioned by police about it being to powerful haha.

That will work out just fine for you unless the cops are on the 'net inch:

Sorry to OP for getting a lil off topic here but i thought it important seeing your wishing to keep within the law. I wont enter into an argument with safe from what i have seen on this forum he just doesn't give up just goes on and on and on haha

No prob. He's got a point for hub motors, of course, and there's no denying that measurement at the wheel is technically more consistent, but the law does clearly state "power delivered by motor" not "power delivered by tyre" at this point - if that were not the interpretation, the NSW RTA wouldn't have made a big deal in it's proposal about changing to measurement at the tyre.

 

[pedalless]

I think seeing e-bicycle are not yet popular in Australia we will get away with
flying under the radar if we ride sensibly. The 49cc motors are ilegal yet there is many members i have seen from Australia on this site that have had no issues and their bikes are much more distint than a hub motored e-bicycle.

More importantly how are things with your motor? and have you had a chance to checkout Endless Sphere? i really think you will be impressed by the information available there, it was very helpful in my e-bicycle choice.