ES DIY Motor Challenge

[enoob]

overheated the magnet rotor & the epoxy flowed. interesting gizmo ( I am thinking a simpler friction brake will have to suffice)

sounds like fun to me . i woulda had a blast with ya .

E, how are you going to test your motor?

lol now this is funny . im making 2 and sending one to you to test.

no really . check this out


im sure you recognize the paper glued to the rotor blank there. horrible failure that one. after a few attempts at getting what i wanted out of my wood working gear i retreated and i am picking up the first version (done on an endmill) in the morning right after i drop the boys at school.

im getting enough magnets to make at least 3 of these . so im lookin at you if your willing to find and old alternator to take a rotor and stator ill send ya. may only make one halbach a conventional nsnsns with 20 magnets is the backup.

[etard]

Awe Cmon Matt, you aren't gonna let the other guys have all the fun here! Are you?

So what are the parameters here in case one were to imagine that they could build something like this? Does it have to at least be within certain weight restraints, and spin at least within a usable rpm, with maybe universal shaft size for testing purposes? Hopefully the perfect ebike motor will be created here.

[enoob]

how are you going to test your motor?

sorry thud it just occured to me that you were asking what i was going to use to spin it up .

could be a good one to add to the parameters of competition ? common controllers for testing .

i was thinking this
https://www.kellycontroller.com/shop/?m ... uct_id=523
or this
http://www.hobbycity.com/hobbycity/stor ... oduct=6550

one choice is budget and i wont mind so much when it smokes, the other i have not looked into fully yet but i would be leaning to the kelly if i can rebuild it though it needs hall sensors .i think.
another outfit that shall go nameless till i get the goods i paid for will NOT be getting used for the virgin run.

[AussieJester]

I am good at implementing someone else's motor onto a bike. It is cool to see people actually start from scratch and make their own working motor.

Matt

Yes im a bit in that boat myself Matt, after rewinding an old Unite motor i had had enough much more pleasurable watching others do it IMO LoL

KiM

p.s good luck all ripper job thgus far too enoob..

[Miles]

So what are the parameters here in case one were to imagine that they could build something like this? Does it have to at least be within certain weight restraints, and spin at least within a usable rpm, with maybe universal shaft size for testing purposes? Hopefully the perfect ebike motor will be created here.

4Nm of continuous rated torque per kg of motor weight - passive cooling only - for a motor weighing under 3 kg?

[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?