ATOMO:  The Electric Bike Project

Long-Distance Electric Bike created from 'cruft'
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

Teaser Images:

Part 1: Getting a grounding: Define the goals
Goal Details.. Priority Level
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:
Cambridge Mass (MIT) is an exciting place on weekends, Manchester... not so much. This is basically so i can get there without burning 20 bucks in fuel every time i visit. its an hours drive and traffic sucks in boston, not to mention that people there are insane drivers
TLDR, there's nerdy folks @ MIT to rock out with.

Part 2: Collecting The Parts:
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)
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
Battery Charger Homebrew. 38V, 10/15A. 2-3 hr charge time.  24 Images and Schematics Will be posted pending further tests.

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

So what i wanted to achieve was kinda different, and required mashing 2 rear wheeled tires (freewheels) to a normal frame. here's why:
In case 1, its a normal bike with a lot of extra mass, the motor and drive train for the electric side are completley isolated from each other, and pedaling isnt loaded by the motor, it actually doesnt move the chain at all (thus the 2 free wheels). In case 2, the system is a purely electric bike, it has a fixed gear ratio, and is front wheel drive, when the motor is over driven (bike is going faster than motor, like in a long down hill, the motor isnt forced by the wheel, its in a freewheel state. also the pedals arent forced to spin up when the motor is on, they are also in a free wheel state In case 3, the system is a parallel hybrid, wherein rear wheel propulsion is provided by the human, and front wheel propulsion is provided by a motor. This instance would happen when the cycle is started up from a complete stop, like after a red light.
[Build Process]
The gearing. Holy smokes its over sized.
the main sprocket was free, courtesy of MIT FSAE getting rid of it. as you can imagine, its overkill. however free is free, so i designed with it.
after basking in the glory of this sprocket, i fabbed up an adapter for mating the gear to the 'free wheeling' part of the bike tire.
Stuff i need to document... Stuff i need to document...
To increase the carrying capacity of the rear portion of the cycle, iron plates were added to either side
A Cycle Retro-fitted for Two
The rear mounting bracket (for the battery pack - person carrier combo)
square tube stock was used for the foot-hold.
This is implemented on both sides
To prevent:
1. things from falling on the battery pack and shorting out
2. corrosion of the battery pack
3. any secondary riders of said cycle from being shocked

I added rubber matting battery covers
they are removable, and 'comfy' for the second rider.

alright, 'more comfortable' than just riding on the battery pack. not 'comfy'

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:
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

Video Footage of Operation

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1st Motor Test
early morning @ ERS

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Electric Bike Test 1 Person
1 person, 600w motor, test in Cambridge MA

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Electric Bike test 2 PERSONS
2 person transport, ~600w motor. Test 2 footage
note: night time test, Cambridge MA

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Brave Travelers
This image was taken after the 2 person bike test. The Tire was originally scrapped together from a bicycle graveyard. The mass of 2 humans + a pile of batteries pushed said tire out of spec and it failed miserably. Fortunately, it held up throughout the test run, like a champ.
Emily K.= the first, second passenger on the cycle. She survived the excursion unscathed, a brave soul indeed.
next up:
hunting down a solid rear tire.
The Maiden Flight of ATOMO:
Images From The Ride Between States
                            Coming Soon!



Thanks for the help:
Charles Guan, http://www.etotheipiplusone.net/
Andrew Armenia, http://www.asquaredlabs.com/

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

Rensselaer Polytechnic Institute 
Electrical & Electrical Power

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