Carbon Brushes; Stator - Husqvarna DM220 Workshop Manual

8
Max 10 mm
1
3
5
16

CARBON BRUSHES

2
4
6
Replacing the carbon brushes
The two carbon brushes transfer electric current to the motor's rotor. A cable
from the stator is connected to the screw in the holder. The carbon brush's
line is connected to the same screw.
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/.4 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 the brush 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 collector down, 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
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 guard.
3. Loosen the screw.
4. Pull out the cable lug
5. Lift the spring and pull out
the carbon brush.
6. Fit a new carbon brush.
Carbon brush holder
Remove the carbon brushes.
Remove the screws at the electro-
nic box allowing the brush hol-
ders to be moved out.
Replacing the carbon
brushes
1. Remove the inspection cover's two
screws.
2. Lift off the guard.
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 angular hook
and pull out the carbon brush.
6. Fit a new carbon brush. The carbon
brush's cable lug must be furthest in.
Turn the carbon brush so that the cable
runs over the carbon brush.
Carbon brush holder
The rotor does not need to be disassemb-
led to replace the carbon brush holder.
Remove the carbon brushes. Remove
the screws that hold both the electronics
box and the brush holders in place.
Note when re-assembling that the
carbon ring lug should be closest to the
holder and the cable to the top of the

stator.