Guardian 4389 Repair Manual page 78

SECTION 4.2
OPERATIONAL ANALYSIS
This "Operational Analysis" is intended to familiarize the service technician with the operation of the DC control
system on prepackaged units with air-cooled engine. A thorough understanding of how the system works is
essential to sound and logical troubleshooting. The DC control system illustrations on the following pages include
a "V-Type" prepackaged transfer switch.
See Figure 1, above. The circuit condition with the AUTO-OFF-MANUAL switch set to AUTO and with "Utility"
source power available can be briefly described as follows:
11
22
11
22
4
ELECTRONIC C2-10
4
VOLTAGE
REGULATOR 0
6
162
CB2
C2-8
DIAGRAM KEY
BA - BRUSH ASSEMBLY
BCR - BATTERY CHARGE RELAY
CB1 - CIRCUIT BREAKER, MAIN OUTPUT
CB2 - CIRCUIT BREAKER, ALT. EXCITATION
CB3 - CIRCUIT BREAKER, EXTERNAL OUTLET, PUSH/PULL
D - DIODE
FS - FUEL SOLENOID
F1 - FUSE 15 AMP
F2 - FUSE 7.5 AMP
HTO - HIGH OIL TEMPERATURE SWITCH
IM1 - IGNITION MODULE, CYLINDER #1
IM2 - IGNITION MODULE, CYLINDER #2
LOP - LOW OIL PRESSURE SWITCH
SC - STARTER CONTACTOR
SCR - STARTER CONTACTOR RELAY
SP1, SP2 - SPARK PLUGS
SW1 - AUTO / OFF / MANUAL SWITCH
SW2 - SET EXERCISE SWITCH
SM - STARTER MOTOR
TX - TRANSFORMER, 16 Vac 56 VA & 16 Vac 1 VA (DUAL SEC.)
= 12 VDC ALWAYS PRESENT
= AC VOLTAGE
= GROUND FOR CONTROL PURPOSES
Page 76
INTRODUCTION
UTILITY SOURCE VOLTAGE AVAILABLE
11
3
2
1
BATTERY
CHARGER
13
2
1
0
13
C2-1
77
BATTERY CHARGE
WINDING
0
C2-4
C2-11 0
BA
0
FIELD
0
C2-9
0
C1-6
6
0
C2-7
2
DPE WINDING
(STATOR)
22
225A
224A
225B
224B
7 7 7 7 9 9 9 9
1 6 3 3 4
77
66
66
C2-2
0
0
HTO
0
55
ENGINE RUN
WINDING C1-4
(STATOR)
C2-3
4
66A
85
351
1 2 3
J2
CONTROL
PRINTED CIRCUIT
BOARD
= 12 VDC DURING CRANKING ONLY
= 12 VDC DURING ENGINE RUN CONDITION
PART 4
DC CONTROL
13
BCR
13
0
14
0
LOP
SW2
14
C1-3
86
4
66A
4 5
23
1 4
J1
194
2
86
3 23
4
194
5
56
6
18
7
14
66A
9
239
15A
17
11
12 15
13 0
14 225
15 224
16
17
11
22
225A
224A
225
224
0 0
13
0 0
13
15A
23
194
225
14
224
239
66A
15A