The Challenge: Generate electricity
Page: 1 2 3 4 5 6 7
Building the Generator
Your generator will consist of a coil held close to a spinning magnet. Cut out two cardboard
discs roughly 3cm (1 in.) in diameter, and make a 4-5mm (about 3/16 in.) hole in the center
of each. Insert the nail in the hole and push one disc up to its head. Cover
the next 2-3cm (3/4 - 1 in.)of the nail's surface with a couple of layers of
the other disc until it butts up against the tape, and then wind more tape
on the other side of it to fix it in position so that the cardboard discs
are no more than 2-3cm (3/4 - 1 in.) apart. Unwind 30cm (12 in.) or so of wire from the reel
to form a lead from the coil, and start winding the remaining wire around
the insulating tape between the two cardboard discs. To keep track, it may
help to make a tick mark on a piece of paper after every 100 turns. The
number of turns is not critical, but the more the better; 1500 turns should do.
Having covered the nail with a single layer of turns, continue building
up layers one on top of the other. You don't have to do a particularly
After about 1500 turns, leave about 30cm of wire free at the other end and then cover
the windings with insulating tape. Remove 1 cm (0.4 in.) or so of the insulation from
the two end wires by scraping off the enamel, and connect them to the socket. Fit the
bulb into the socket.
bolt through the hole drilled into the base of the magnet, and fasten it
by tightening the nut. Fix the bolt into the chuck of a hand drill. Next,
fix the sharp end of the nail in a vice (or between two heavy books) so
that it's horizontal. Bring the magnet to within about 1mm (about 1/16 in.)
of the nail head, which should be slightly off-center from the middle of the spinning
magnet. Make sure the gap between the magnet and the nail head is as small
as possible, but not so close that they touch. A tip here is to rest the
hand holding the fixed part of the drill on the table-top so that it's
as steady as possible.
Turn the drill handle as fast as you can and the bulb should light up. Generating
electricity really is as simple as this!
Generators in cars and bicycles