helo guys,

i am a first year engineering student and i have a project to build a space elevator that will climb 10m tether by end of may. The problem here is that i am working on the climbing mechanism for my elevator and still havent decided on which type of mechanism will work on it. i figured out several possible design solution, such as using wheels and magnet. but i am more interested with the magnet design.

http://i60.photobucket.com/albums/h2/c2v4l/clip_image002.jpg
*take a look on the magnet sketch

The elevator will work with the electricity generated with 2 solar cells which are almost the same size as A4 paper. i have no idea how much electricity will it generated but i was also given a motor and gear which needed 2 AA battery to work. my question here is that..will the attraction and repulsion of the magnet(on the wheel is permanent magnet and the coil is induced to be a magnet while electric flowing on the coil) drive enough force to move the elevator up the tether? i suspect that the mass of the elevator will be quite close to 5kg.

all i want to know is that whether the electricity from the solar cell be able to produce a strong induced magnet(the coil) so that it can move the elevator. so anyone who are really an expert in this area hope u guys can help me on this.

I am not an expert in this, but I doubt the solar cells would be able to produce sufficiently high current to have sufficiently high magnetic field.

Are the solar cells compulsory? Can you perhaps use other alternatives? A transformer to downstep 240 V of power from the main power supply can be an alternative.

Solar cells outputs about 120W per square meter. For an area of an A4 paper, the power is about 7.5W. This is when the sunlight is bright enough, as in afternoon, and the cells oriented at a correct angle.

Computer optical drive spindle motor has roughly that much of power, 10W. That motor can spin a CD/DVD to about 12000rpm.
Another comparison is two NiMH AA batteries can supply 7.5W for about 35 minutes.

Lifting 5kg up 10m needs 490J of energy. At a rate of 7.5W, it needs slightly more than one minute. And this haven't taken efficiency into account. But can estimate in the end, it takes about two minutes.

yup..the solar cells is compulsory..

i am more than satisfied if the elevator take 10 mins to climb up and down..and i was thinking of using some kind of switch or controller so that when it hit the top it will automatically cut off the electricity and make the wheels rotate the other way around so that it will fall(climb) down by its own weight. actually, i dun really bother with its journey down because what is more important is to make it all the way to the top( i doubt all the other groups will be able to do this).

there are a total of 12 groups doing this project and from what i can tell, almost all of them using wheels to climb the tether..the main problem with wheels is that it is easily going off the track(the wheels slip up from the tether - we use nylon strap as the tether -its dimension is 2.5cm wide and 0.5cm thick)..

i got to go now. my class is in 30 mins