Stator Assembly; Brush Holder And Brushes; Other Ac Generator Components - Guardian 5240 Diagnostic Repair Manual

AC GENERATORS
Figure 2. The 2-Pole Rotor Assembly

STATOR ASSEMBLY

The stator can houses and retains (a) dual AC power
windings, (b) excitation winding, and (c) battery
charge winding. A total of ten (10) stator leads are
brought out of the stator can as shown in Figure 3.
The stator can is sandwiched between an engine
adapter and a rear bearing carrier. It is retained in that
position by four stator studs.
Figure 3 Stator Assembly Leads

BRUSH HOLDER AND BRUSHES

The brush holder is retained to the rear bearing car-
rier by means of two #10-32 x 9/16 Taptite screws. A
positive (+) and a negative (-) brush are retained in
the brush holder, with the positive (+) brush riding on
the slip ring nearest the rotor bearing.
PART 2
2
6
11P
11S
22P
22S
44
66
77
DESCRIPTION & COMPONENTS
Wire 4 connects to the positive (+) brush and Wire 0
to the negative (-) brush. Wire 0 connects to frame
ground. Rectified and regulated excitation current, as
well as current from a field boost circuit, are delivered
to the rotor windings via Wire 4, and the positive (+)
brush and slip ring. The excitation and field boost cur-
rent passes through the windings and to frame ground
via the negative (-) slip ring and brush, and Wire 0.
This current flow creates a magnetic field around the
rotor having a flux concentration that is proportional to
the amount of current flow.
0
Figure 4. Brush Holder and Brushes

OTHER AC GENERATOR COMPONENTS

Some AC generator components are housed in the
generator control panel enclosure, and are not shown
in Figure 1. These are (a) a voltage regulator, and (b)
a main line circuit breaker.
VOLTAGE REGULATOR:
A typical voltage regulator is shown in Figure 5.
Unregulated AC output from the stator excitation
winding is delivered to the regulator's DPE terminals,
via Wire 2 and Wire 6. The voltage regulator rectifies
that current and, based on stator AC power winding
sensing, regulates it. The rectified and regulated exci-
tation current is then delivered to the rotor windings
from the positive (+) and negative (-) regulator termi-
nals, via Wire 4 and Wire 0. Stator AC power winding
"sensing" is delivered to the regulator "SEN" terminals
via Wires 11 and 22.
The regulator provides "over-voltage" protection, but
does not protect against "under-voltage". On occur-
rence of an "over-voltage" condition, the regulator will
"shut down" and complete loss Of excitation current
to the rotor will occur. Without excitation current, the
generator AC output voltage will drop to approximately
one-half (or lower) of the unit's rated voltage.
SECTION 2.1
4
- +
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