Dane.Kouttron
ATOMO: The Electric Bike Project
Long-Distance Electric Bike created from 'cruft' What?An
electric Car would be Sweet. I
got to play with all sorts of
electric and hybrid vehicles over @ GM last summer, but affording one
is another thing entirely. This project revolves around building an
electric bike from scratch, paying as little as possible while having a
range of 40 miles. Try finding an electric-hybrid bike that'l do 40
miles for cheap. a
friend built an electric motorcycle,
its awesome, and i needed one,
albeit less motorcycle more bike. Being able to tool @ MIT made this
all the more possible
Project Goals | Collecting Parts | Mechanical Layout | Drive-Train & Hardware | Converting an alternator into a 3 phase PM Motor | Video & Test Footage! | 2 |
Goal | Details.. | Priority
Level (0=low,9=high) |
Sustain
30mph
(in electric assist
mode) |
I want to get places in a moderatley fast manner | 9 |
Being legal to drive | The transport should be legal enough so that i don't get recursively ticketed | 1 |
charge
in less than 3 hours |
and have the charger on the cycle (portable) | 8 |
Have a 1950's asthetic | I had the privledge of watching some friends play Fallout3, and i really liked the postnuclear asthetic. I wanted to find a way of shoving it into this project. | 5 |
Sturdy Mechanical Stuff | if the cycle is going to travel 40 miles, it should actually do so without requiring constant maintainance | 9 |
MAKE IT FROM MANCHESTER TO CAMBRIDGE | make it from my place of internship (NH) to Cambridge (MITERS). Without myself or the cycle dying (at a 40:60 ratio of biking to electric power riding) | 9 |
Make
a small radioisotope based power supply for battery maintainance. (Beta
source based) |
Unfortunatley its very difficult to actually have a licence to do this, so i ended up having to abandon adding it to the cycle. Prototype reactors were built but not tested, due to lack of fuels | x |
The
real goals:
ITEM | Details | Cost | Image |
A Bike | i
Craigslisted a bike, 25 dollars. Took
2 weeks to find a cheap bike, but it was worth the wait (not a pic of the actual bike but rather close) |
25 | ![]() |
The Batteries | This is key, batteries are the achilllies heel of any project. I managed to get NiZn recycled forklift batteries via a friend (john you rock). Yea, NiZn, i had no idea they existed in this format either. Check your local recycling center, or just ask around Craigslist. I scavenged somewhere near 36V at 30AH of power. total mass is less than 40lbs. | 36 | ![]() |
The Motor | Defunct Alternator. defunct from lack of brushes for field winding, then again, i didnt really mind, as i wasn't planning on using them. | free | ![]() |
Controller | Homebrew | 12 | Images and Schematics Will be posted pending further tests. |
Gearing and Chain | Mcmaster (#50 chain + 9 tooth sproket) Sprocket: link Chain: link |
20 | |
Battery Charger | Homebrew. 38V, 10/15A. 2-3 hr charge time. | 24 | Images and Schematics Will be posted pending further tests. |
DESIGN and BUILD
The
design of the cycle
is,
well kinda ridiculous. Quite a number of modifications were necessary
to achieve the necessary structural stability and handing for proper
operation. FEA was used on the front end to determine long term
stability. <insert FEA model>
Issue#1&2, Mechanical Stability and The Drive Train
[Design]
So what i wanted to achieve was kinda different, and required mashing 2 rear wheeled tires (freewheels) to a normal frame. here's why:
Issue#1&2, Mechanical Stability and The Drive Train
[Design]
So what i wanted to achieve was kinda different, and required mashing 2 rear wheeled tires (freewheels) to a normal frame. here's why:
Issue#3, Starting torque kinda sucks
The first motor i used was from some really old electric transport for some child, I started designing around it, assuming the 400-600 ish watts of output power would be sufficient. It was horribly under powered, so the next logical bet was to make/find a motor. After some thinking i came to terms with the idea of retrofitting an automotive alternator to becoming a 3 phase motor.
My original Motor, Scavenged and underpowered (mabye 400W) | ![]() |
Whats the difference between an alternator and A 3 phase motor ? not so much
HOW TO CONVERT An ALTERNATOR into a 3 PHASE permanent Magnet Motor
1 Get a crufty alternator | Locate an alternator, scrap yards or wherever. | a 'random alternator' should run you 30 bucks if not free. |
2. Open the alternator | Chances are its rusty, use some sort of penetrant (liquid wrench / homebrew) |
![]() |
3.Remove Electronics | Basically the 'electronics' for the alternator is a 3 phase bridge rectifier and a device to modulate the field current based upon alternator loading. remove it, there should be 3 inputs going to it. | CUT OUT THE PLASTIC ELECTRONICS BOARD ITS NOT HARD |
4. Attach three phase outbound cables | There should be 3 or 4 wires coming from the alternator (wye or delta configuration, where wye has the centertap connected). either work perfectly, assuming you can build a 3 phase motor drive for either. | ![]() |
5.
Make A new ROTOR [Take measurements] |
ok, so you've got a beautiful 36 pole motor winding assembly, and you want to make a 12 pole rotor: crank up solidworks, do some cad'ing and make some measurements. you want to use an iron or other permeable material. no aluminum. | ![]() |
6. Order some magnets | go
here: http://www.supermagnetman.net/index.php |
Find a good magnet for your sized rotor. note the 12:36 ratio works really well. (36 poles, 12 magnets) im using 1/4* 1/2 * 1.5" N40 magnets. sufficient strength for this purpose |
7. match and wrap motor core | Documentation will be added shortly | Documentation will be added shortly |
PAINT: Before and After
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Video Footage of Operation
1st Motor Test early morning @ ERS |
|
Get Flash to see this player. |
Electric Bike Test 1 Person 1 person, 600w motor, test in Cambridge MA |
Get Flash to see this player. |
Electric
Bike test 2 PERSONS 2 person transport, ~600w motor. Test 2 footage note: night time test, Cambridge MA |
Get Flash to see this player. |
ELECTRIC BIKE- 2 Person TEST 2 (ACTUALLY IN DAYLIGHT) (Turn UP SPEAKERS) (music= LIGHTNING-BOLT) |
References:
MITERS IS THE MOST AMAZING THING SINCE SNACKPACKS™
THANK YOU FOR LETTING ME USE YOUR TOOLS AND YOUR SHOP AND YOUR SPACE
Thanks for the help:
Charles Guan, http://www.etotheipiplusone.net/
Andrew Armenia, http://www.asquaredlabs.com/
notes:
why does this page look like it was designed in the 90's:
Because it works, im not a web artist. There's no twitter links, there's no 'Digg this' garbage, the internet survived before that.
Also if your stuck in an office on a mandated IE6 browser, everything here is readable. Your welcome.
Why is it all on one page
Do you like multi-page add filled links? i dont either
Is this bike thing legal?
Check your country laws, If your in the US, Follow this (link below), basically under 750W, and sub 20mph = legal. Again, check your local laws
www.iloveebikes.com/Distributorfiles/FEDregulation.pdf
Dane.Kouttron
Rensselaer Polytechnic Institute
Electrical & Electrical Power
631.978.1650
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