Tzortzakakis Dimitrios said:
Are you kidding?We made one in science (high school) with nails, and copper
wire.It had the size of a cigarette packet.DC motor, with commutator, shunt
(not series).But the fool of a professor didn't return me the book (with the
instructions).It was in greek, anyway.It's impossible to make an ac motor on
your own.The principle of ac motors is the rotating magnetic field (or
squirrel cage motors).There's no commutator or brushes.Imagine-to weld open
the compressor of your refrigerator to have the brushes changed.It would be
very dangerous, too, to use the mains for experiments.Search at your local
bookstores.
As far as making an AC motor on your own- it is actually simpler than making
a DC motor if you have a 3 phase supply. Simply take 3 coils (such as the
field coils of a DC machine) arranged in a triangle.Connect as delta or star
to a 3 phase supply. In the center of the arrangement put some sort of
pivot. Get a coke or beer can, drop it on the pivot and energise the coils-
Voila- an induction motor. Paper clips also work. Put a small compass needle
in the center of the coil triangle- Voila- a synchronous motor. Been there,
done that. A single phase motor - use 2 coils at right angles and feed one
through a capacitor (could use a resistor but with such a primitive
construction a capacitor is better.
Otherwise simply use a DC series motor on AC. Commonly used commercially-
called a universal motor.
The DC motor with nails and crude commutator appears in many "how to " books
for well below high school level students and experimentors.
However- your comment on playing around at mains voltage is quite correct.