Brush Holder; Battery Charge Components; Excitation Circuit Components - Guardian 4270 Diagnostic Repair Manual

3. Two excitation winding output leads (No. 2 and 6). These leads
deliver unregulated excitation current to the voltage regulator.
4. Three (3) battery charge output leads (No. 55, 66 and 77).
Leads 2 & 6 =Stator Excitation Winding
Leads 11 & 22 = Voltage Sensing Leads
Leads 11 & 22, 33 & 44 = AC Power Windings
Leads 55, 66, 77 = Battery Charge Windings
Figure 2-2. – Stator Output Leads

BRUSH HOLDER

The brush holder is retained in the rear bearing carri-
er by two M5 screws. It retains two brushes, which
contact the Rotor slip rings and allow current flow
from stationary parts to the revolving Rotor. The posi-
tive (+) brush is located nearest the Rotor bearing.
Figure 2-3. – Brush Holder

BATTERY CHARGE COMPONENTS

The Stator incorporates dual battery charge windings.
A battery charge rectifier (BCR) changes the AC out-
put of these windings to direct current (DC). Battery
charge winding output is delivered to the unit battery
via the rectifier, a 14 amp fuse and Wire No. 15. A
one ohm, 25 watt resistor is connected in series with
the grounded side of the circuit.
2
6
11
11
22
22
44
55
66
77
BRUSHES
MAJOR GENERATOR COMPONENTS
BCR
TO BATTERY
15
77
BATTERY CHARGE WINDING
R1
0N
BCR = Battery Charge Rectifier
R1 =
Figure 2-4. – Battery Charge Circuit

EXCITATION CIRCUIT COMPONENTS

GENERAL:
During operation, the Rotor's magnetic field induces a
voltage and current flow into the Stator excitation
winding. The resultant AC output is delivered to a
voltage regulator via an excitation circuit breaker
(CB2).
POWER WINDING
22S
ELECTRONIC
VOLTAGE
REGULATOR
0K
2A
CB2
2
DPE WINDING
0F
Figure 2-5. – Schematic: Excitation Circuit
EXCITATION CIRCUIT BREAKER:
The excitation circuit breaker (CB2) is self-resetting
and cannot be reset manually. Should the breaker
open for any reason, excitation current flow to the
Rotor is lost. The unit's AC output voltage will then
drop to a value equal to the Rotor's residual magnet-
ism (about 7-12 VAC).
Section 2
TO ENGINE
CONTROLLER
CIRCUIT BOARD
66
66
55
One Ohm, 25 Watt Resistor
11S
4
6
4
FIELD
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