PREVOST LE MIRAGE XLII BUS SHELLS User Manual

Section 22: HEATING AND AIR CONDITIONING
PA1553
25
Replace the brushes if less than ¾ inch (19
mm). New brush length is 1-¼ inch.
To replace brushes, proceed as follows:
1. Set ignition key switch to the “OFF” position.
2. Remove the protective screen band from the
motor housing by pulling down the spring
loaded fastener.
3. Lift the spring, remove and replace brushes
as per the following procedure: “SEATING
BRUSHES”.
4. Reverse installation procedure.
9.3.5 Seating Brushes
Grinding consists in giving to the seating face of
a new brush the exact same curvature of the
commutator so that good mechanical and
electric contact of the brush is made.
For best results, remove oil and grease from
commutator before applying brush seater.
NOTE
The new motor brushes are provided with a
preformed seating face which is approximately
the same curvature as the commutator.
Grinding/honing will give an exact match in
curvature. The advantage of preforming is to
appreciably shorten the time required for
grinding.
Grinding is generally done on the machine itself,
in accordance with various processes' and
conformably to the importance and the type of
machines:
a) Grinding with abrasive cloth (60 grit
sandpaper) applied to the commutator must
be done by hand. With the new brushes
installed in brush holders and pressing
against the abrasive cloth, rotate the
armature (by hand) until satisfactory seating
of each brush is achieved (Refer to figure
25). It is necessary to avoid raising the cloth
under the brushes otherwise it would result,
after grinding, to reduce and badly definite
surfaces (Refer to figure 26).
FIGURE 25: PROPER GRINDING TECHNIQUE 22317
FIGURE 26: IMPROPER GRINDING TECHNIQUE 22318
CAUTION
If grinding with a honing stone, you must
disconnect the time delay in order to keep the
motor in 1
st
speed. If you prefer, you may also
install a jumper on the evaporator motor
between terminal E2 and A1 to bypass relay
R60 and keep the motor in 1
st
speed as well.
b) Grinding with the honing stone is always
done under reduced voltage. Dust particles
act like abrasive and wear down the brushes
exactly with the profile of the commutator.
Caution is advised here as prolonged
honing could wear the brushes and
commutator prematurely.

PREVOST LE MIRAGE XLII BUS SHELLS Specifications

General

Brand	PREVOST
Model	LE MIRAGE XLII BUS SHELLS
Category	Buses
Language	English