• Draw 3 more pairs of straight lines at 45 and 90 degree angles to the first pair.
• Using these lines, mark the magnet positions, and cut out the jig along the bold
lines as shown in the diagram.
• Draw a line connecting two opposite magnet centres.
• Place the PCD jig on top of the 102mm circle, aligned with the magnet centres,
and drill four holes to match the four holes in the steel disks.
Making the moulds
Make moulds for the stator and rotor castings. They can be turned from wood or
aluminium. Another method is to make plaster or clay plugs on a wheel, like a pot.
The shape of the plug would be the shape of the outside of the stator. Then make a
fibreglass mould on the plug. The surface of each mould must be perfectly flat.
The moulds need to be strong and smooth. It is not easy to separate the stator
casting from the moulds. Hammer blows are usually needed.
It is a good idea to wind one coil (see section 4) before making the stator mould.
This coil should fit neatly in the mould.
Here is one way to make the moulds, from composite wooden floorboard sheets,
using wood-turning.
Stator Outer mould
• Cut out several disks of flooring sheet (see diagram 13), approximately 500mm
diameter.
13. DISKS
500
20
PMG manual
page 15
June 2001