ES DIY Motor Challenge

[Miles]

Perhaps we need to clarify "passive cooling"?

Maybe we should allow cooling systems that are driven by the motor itself, but not those that use an autonomous fan or pump?

[TylerDurden]

Perhaps we need to clarify "passive cooling"? Maybe we should allow cooling systems that are driven by the motor itself, but not those that use an autonomous fan or pump?

Sounds like a good distinction between classes.

[Miles]

Perhaps we need to clarify "passive cooling"? Maybe we should allow cooling systems that are driven by the motor itself, but not those that use an autonomous fan or pump?

Sounds like a good distinction between classes.

For good reason, no?

[TylerDurden]

For good reason, no?

Sure.

Having the classes discrete will bring more innovation in each one.

[liveforphysics]

As a guy with an abnormal amount of exposure to contests, you're really going to need to make a rule-sheet, and choose the wording extremely carefully. Wording related loop-holes are what get most racers the win.

You can also make the broad, "Any interpretation deemed to be outside the spirit of the event" statement at the end of the rule sheet, but it kinda bogs down potential creativity, and in this contest, creative solutions/designs are more the idea rather than a fair event. My $0.02.

Just remember, the moment you make a new rule, you also open a new can of worms, so they need to be choosen and then phrased very carefully.

[Miles]

No kudos in a win that isn't in the spirit of the challenge.

[liveforphysics]

I used to feel that way Miles. After you start running against teams with massive sponsors and high 6-digit yearly budgets, and you're running a self-built grass-roots self-budgeted racing effort, you find creative interpretations of the rule book to be that bit of anything to do more than bring home, "also-ran" positions at events...

Its very tough when you gotta run a season on 1-2 engines and 2-3 trannys and 2-3 sets of tires when you run against teams that bring 2 full semi-trucks out, one having a portable machine shop and filled with engines, the other having a few chassis and 20 new slicks. I'm driving my own car there packed with tools and tires and parts, and my driver=my mechanic = my tuner = my engineer = my crewchief. Everytime we take down a factory backed team, its a proud celebration no matter how we managed to do it.

For something all grassroots, I would stick pretty close to the spirit of the event.

[Miles]

[Thud]

As a prize-less competition, I think the fewer rules(?) the better. Its not about fair or winning, its about a home made motor the meets the tourqe density requirement in the OP. (as reasonably cost effective as possible in my case)if some one has unique skills to add to their build I would like to see it.(water cooling,cold fusion,horse manure)

I like the word "Challenge" in this instance over competition. If its a "competition" I have to re-focus & pinpoint on a goal & do all in my power to WIN! (I come from a long line of competitive people)kudo's be dammed. A win is a win.

Rules & constraining critera are great for a real "competition" but they also tend to drive costs up & can bewilder some from participation. They are ment to level the playing feild. The only catagory I feel is required is "electric motor".

I would think if the need arises, we can create all the defining launguage for the motors as they present themselves

I still have the feeling this is going to be a long lived thread. So far I can only see Enoob & myself activly working on a motor build currently. In a few months or years I would hope to see some joiners.

Can we get a "roll call" from those who plan to build one someday? even if its a knock off of a proven design.
or a cad model to share. That could be another catogory.

[Miles]

How about:

Over 4Nm continuous torque per kg of motor weight.

Less than 3kg in weight.

No energy input other than that to the motor itself.

Capable of practical use on an electric bike.

[TylerDurden]

I like the word "Challenge" in this instance over competition. If its a "competition" I have to re-focus & pinpoint on a goal & do all in my power to WIN! (I come from a long line of competitive people)kudo's be dammed. A win is a win.

Yeah, 'challenge' is good.

Like HPV events, this is research... Participants should publish a replicable process.

[enoob]

if theres one thing "competition" is sure to do its start a debate.

i like the simple measure of torque per kg of weight . id bet the rest will settle from there . more rules mean more room for interpretation . i for one know for a fact that other people are going to spend more than me to make a one off. i also know that others will make more power than i will BUT thats not the contest to me . i suspect as another poster here has that this may lead to the perfect ebike motor. the only problem with that statement is the perfect ebike motor will be different for each user. some will ignore cost and jump at power output and a pretty package . others will think the perfect ebike motor is sitting in a scrap heap waiting to get rebuilt.

my perfect ebike motor will be easy to work on cost little and move me around. so thats what im working on. if i can get it done myself and it can be reproduced for less than $100 as far as im concerned its a win.
not that it will beat all comers but to me its a winner.

in the end isnt the point to get on an ebike and out of the cage? so anything that helps that along is a winning effort.

[liveforphysics]

Like HPV events, this is research... Participants should publish a replicable process.

Before I realized that must be "Human powered vehicle", all I could think of was "Human Papilloma Virus." I was shocked to hear this was an event people would choose to compete in.

[liveforphysics]

With continuous specific torque/weigh ratio being the winning objective, I'm envisioning a 20" thin CF rotor with a hundred 1/16" thick small arc magnets around the outside, and a thin fiberglass rotor with 60 flat wound 3mm thick ironless coils and a graphite lubed interference-fit air gap. Wind all the coils in series, and end up with a 10rpm/V 1-2Kg motor weight torque monster. It wouldn't make any power though but it would win.

[Miles]

The motor with the greatest cont. torque density should be capable of generating the greatest cont. power density, too, assuming similar relative speed capability..... Hey, speed/power would be a great way to hold a playoff

[vanilla ice]

I don't get the fascination with torque, power is what we need.. Use that as your metric. Power is usable torque.

[Miles]

It's not a fascination with torque, it's the importance of torque density..... For the purpose of comparing a broad range of motor sizes, torque density is a pretty good measure. It does slowly increase with motor size, hence the 3 kg limit.

Does anyone else disagree with the parameters I've chosen?

[John in CR]

Yes, no weight limit, since torque density already covers mass. That opens it up to more variety, and leaves the decisions of power and weight up to the builder to consider the legalities in their jurisdiction. Also someone may want to DIY an axial flux hub motor, which will add weight just because it's going in a wheel.

John

[Miles]

John,

Like I said, larger motors do have an advantage. That's the reason for the 3kg limit. This is the non-hub motor forum

0.5kg to 3kg should be the range that most people want to work within?

[John in CR]

Rules, rules, rules...some of us don't like rules, and now a better than currently available hub motor can't play. I guess brushed motors are out too...What about 6 phases?...Voltage limits?...Does it have to be a certain color?

[mwkeefer]

John,

Just put the nylon gears back in, seperate the mag ring and drill the thing from the backside divits to reduce weight and finally drill the living crap out of your covers - I'm talking 1" or bigger diameter holes... and run it without any lube - try teflon power like you use for a bowling ball - be sure you have it mounted to a suspension fork and if you still need to loose some weight... well start unwinding every third phase or so... maybe a cromo axle or somthing stronger and lighter than the factory axle? Magnesium is awful light (and as strong as aluminum if cast properly) - Half Kidding

Um... fellas maybe title should include the word Electric, ie: "ES DIY Electric Motor Challenge" - or can I submit the my wenkle design rotary gas powered ebike/lev hub motor? - (Kidding and no, I won't do the photoshop)

I've only ever built 1 electric motor from scratch, I was 6 years old and it was nails, magnets and that Green xmas wire for windings - add 9v battery and a flick of the finger (can you say pedalec) and I was hooked for life.

-Mike

[recumpence]

I've only ever built 1 electric motor from scratch, I was 6 years old and it was nails, magnets and that Green xmas wire for windings - add 9v battery and a flick of the finger (can you say pedalec) and I was hooked for life.

-Mike

Oh, Man, I built one of those myself. I think I was 7 or 8, though. So, you got the jump on me!

Matt

[mwkeefer]

Matt, I hate to admit but I think this is turtle vs hare {I'm the hare, roadkill on I95} and we all know who won that race {hint: its not the guy with the green bailing wire direct drive motor running 9v} - Mike

[spinningmagnets]

Axel from Sweden sent me a rough draft of a manual (with lots of pics) to build a home-made 6" axial-flux 500W@36V motor and DIY opto-controller. It is for an RC plane, and it is only one-phase. He has recieved a lot of interest and is putting together a tutorial for a much larger 3-phase axial (should be available in 6 months), which he plans to sell the PDF for a modest price.

I plan on scaling down his 3-phase motor to a 1,000W@48V to power a DIY longtail bike. I just picked up a used Sturmey-Archer 3-speed hub I hope to use as a jackshaft/transmission, and I may go ahead and build the bike with a temporary TNC motor as it will be months before I will even start building an "Axel"-motor. At this rate, it might take 9 months, wish me luck...

[amberwolf]

Um... fellas maybe title should include the word Electric, ie: "ES DIY Electric Motor Challenge" - or can I submit the my wenkle design rotary gas powered ebike/lev hub motor? - (Kidding and no, I won't do the photoshop)

Something like this, but using Wankel?
http://en.wikipedia.org/wiki/File:Felix_Millet.jpg