Carbon Brushes - Husqvarna DM 330 Workshop Manual

Max 10 mm
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CARBON BRUSHES

Replacing the carbon brushes
The two carbon brushes transfer electric current to the motor's rotor.
The carbon brushes are wear parts that must be checked regularly. Every
week if the machine is used on a daily basis.
You should replace the carbon brushes when around half is left. You can
easily measure this using a slide gauge without removing the brushes. Replace
the carbon brushes when the distance from the brush holder to the top level
of the brush exceeds 10 mm (1/2 in.).
Worn carbon brushes – checking
The importance of replacing the brushes in good time is demonstrated by the
adjoining illustrations.
The illustrations to the left show a brush that is worn but still operable.
Both brushes and the collector have minor scratches in the direction of rota-
tion which is entirely normal.
The illustrations to the right show the results when the brush is so worn
that the spring, which presses the brush down on the collector, has reached its
end position and no longer gives the brush the correct pressure to the collector.
Sparking occurs which damages both brushes and, even worse, the collector in
a very short time.
Pay careful attention to sparking near the collector
The information given above shows that it is important to avoid sparking
around the collector. If the brushes are not worn, sparking could be due to the
brushes being unable to move in their holders as a result of, for example, dirt.
Replacing the carbon
brushes
1. Remove the screws.
2. Lift off the cover.
3. Loosen the screw one turn.
4. Pull out the cable lug
5. Lift the spring and pull out
the carbon brush.
Clean the holder.
6. Fit new carbon brushes.
Carbon brush holder
1
1. Remove the carbon brushes
and the screw.
2. Fold the electronic unit to
3
one side and remove the screws.
3. Push out the holders.
Replacing the carbon
brushes
1. Remove the five screws tom the
inspection cover. Push the cover back-
wards using a screwdriver in the break
slot next to the leak channel.
2. Lift off the cover. Note the cable
routing.
3. Loosen the screw and screw it out one
turn. Let the screw remain in place.
4. Pull out the cable lug from the screw.
5. Lift the spring with an angle hook. Lift
off the carbon brush.
Clean the holder from carbon particles
and dirt.
6. Fit new carbon brushes. Check that the
carbon brush cable runs over the spring.
Carbon brush holder
1. Remove the carbon brushes and the
screw to the cable lugs.
2. Fold the electronic unit to one side.
Remove the screws to the carbon brush
holders.
3. Push out the holders.
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