Guardian 4389 Repair Manual page 86

SECTION 4.2
OPERATIONAL ANALYSIS
The generator is running, the circuit board's "engine warm-up timer" is timing, and generator AC output is avail-
able to transfer switch terminal lugs E1 and E2 and to the open contacts on the transfer relay. Initial transfer to
the STANDBY power supply may be briefly described as follows:
• The circuit board delivers a 12 volts DC output to the transfer relay (TR) actuating coil, via Wire 194, and termi-
nal A of the transfer relay (TR) in the transfer switch. This 12 volts DC circuit is completed back to the board,
via transfer relay terminal B, and Wire 23. However, circuit board action holds the Wire 23 circuit open to
ground and the transfer relay (TR) is de-energized.
• When the circuit board's "engine warm-up timer" times out, circuit board action completes the Wire 23 circuit to
11
22
11
22
4
ELECTRONIC C2-10
4
VOLTAGE
0
REGULATOR
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 84
INITIAL TRANSFER TO THE "STANDBY" SOURCE
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 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
= DC FIELD CONTROL VOLTAGE
= 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
66A
9
239
15A
17
11
12 15
13 0
14 225
224
15
16
17
11
22
225A
224A
225
224
0 0
13
0 0
13
15A
23
194
225
14
224
239
66A
15A