THE BOX SECTION SPINE

 

DRILL HOLES WITH A PILLAR DRILL FOR ACCURATE ALIGNMENT

7\

Weld the shaft in the 25mm hole. Take care to hold the shaft as square as possible (90 degrees) to the spine, when welding it.

The bearing hub (diagram 40) fits on the shaft. It has two 50x25 mm deep-groove ballraces in it, with a spacer between them. It needs a plastic cap over the end to keep dirt out of the bearings.

Do not forget to grease the bearings. Pack them with grease around half of their circumference only. Do not fill them entirely or they will become stiff to turn.

40. THE BEARING HUB

Ø10

Ø25

25

PCD102

 

show the rear magnet rotor being fitted

PMG assembly

41.STUDS

THREADED ROD

1 0mm

• Cut 4 pieces of M1 0 threaded rod,
each 200 long. They are used as studs
to hold the magnet rotors to the hub.
The wind turbine blades will also
mount onto these studs.

• Put 6 nuts onto each stud) see
diagram 41).

• Fit the studs through the holes in the
bearing hub, from the front

• Put the rear magnet rotor onto the
ends of the studs.

• Put a nut on the end of
each stud, and tighten the
other nuts down, so that
the rear magnet rotor is
attached to the back of
the hub flange. The outer
end nut should be sealed
with paint or thread-
sealant.

• Place the spine in a vice with the
shaft upward. Place the hub onto
the shaft. Do not hammer the
magnet rotor while fitting. Fasten
the hub to the shaft with a nut and
split pin. Do not over tighten the
nut. Fit a dust cover over the end
of the bearing hub.

Rotate the magnet rotor past a piece of brass wire. Do not use steel wire, because it is attracted to the magnets. The magnet faces should all be at the same height +/- 0.5mm. If not, use very thin shims between hub-flange and rotor-disk, to adjust the rotor. Using a spirit level, adjust the spine in the vice until the magnet rotor is level. Check both ways: north-south and east-west. Take the stator. Fit one 8 mm nut onto each support stud. Screw them right down. Place the stator over the rear magnet rotor

 

 

 

 

fit its support studs into the holes in the spine. Fit more 8 mm nuts to the ends of the studs.

Slowly lower the stator, and rotate the rear magnet rotor. Keep the stator level in both directions. You will hear a sound when the highest magnet touches the stator. Use the nuts to raise the stator equally 1 mm on all four studs. Fit some washers to the 10 mm studs which hold the rotors. Always the same number of nuts and washers on each stud. A total of six nuts and two washers may be

Fitting the stator

enough. Then fit the front magnet rotor.

If the front magnet rotor is less than 1 mm from the stator at any point, then add

more washers under it. If it is much more than 1 mm from the stator then remove washers. To find the correct number it is necessary to remove washers unti it begins to rub the stator. Then add 1mm.

• When the front rotor is 1 mm from the stator, then fit more nuts on

Fitting the front magnet rotor

top, and tighten them securely.

Elect rical Parts

The next section (Section 7) will describe how to connect the rectifier to the stator. I recommend using two 'single phase bridge rectifiers' (see diagram 42). They come in blocks 30 x 30 mm. The positive terminals are both connected to the battery positive terminal. (They are often at right angles to the other three. ) Both negative terminals are connect to the battery negative. The remaining four terminals are for AC connection to the stator. You will probably only need to use three of these, connected as desired to suit the speed (see Section 7).