Utility Source Voltage Failure - Generac Power Systems 7 kW NG Repair Manual

TRANSFER SWITCH
If Utility source voltage should drop below 65% of nominal voltage for ten seconds, the controller will initiate engine start. After the
generator starts a five second engine warm-up timer is initiated. During this warm-up the generator is running at rated frequency
and voltage. Figure 67 is a schematic representation of the transfer switch with the Generator running with voltage available to the
transfer switch.
Generator voltage is available on CONTACTOR terminals E1 and E2.
• The controller's logic is holding Wire 23 open from ground.
• Generator voltage from terminal E2 is available at the standby coil (C2); generator voltage from Terminal E1 is available to the
transfer relay at Pin 9. The transfer relay is not energized so E1 voltage will not go through the N.O. contact (9 & 6) to Wire 205.
N1A
7
E1
N1A
126
B
NO
B
N2A
A
B
LEGEND
C1-UTILITY COIL & RECTIFIER
C2-GENERATOR COIL & RECTIFIER
F1, F2, F3-5A, 600V FUSE
LC-CIRCUIT BREAKER (LOADS)
(16 CIRCUIT SHOWN FOR REFERENCE ONLY)
N-NEUTRAL
SW1-AUTOMATIC TRANSFER SWITCH
SW2, SW3-LIMIT SWITCHES
TB1-TERMINAL STRIP
TR1-TRANSFER RELAY
PART 3

UTILITY SOURCE VOLTAGE FAILURE

T1A
E1
194
A
23
7 9 9
TR1
1 4 3 6
B
23
205
N1A
N1A
N2A
E1
N2A
205
B
N1A
126
N2A
E1
NC NC NO
SW3
SW2
COM COM
VR1 VR2
C1 C2
T1A T2
SW1
T1
N2A
B E2
T1A
E2
DC
(PCB) GROUND CONTROL
E1 GENERATOR VOLTAGE
E2 GENERATOR VOLTAGE
N1 UTILITY VOLTAGE
N2 UTILITY VOLTAGE
Figure 67. Utility Source Voltage Failure
EXTERNAL CONNECTION BOX
194
23
F3
T1A T1
F2
N2A N2
F1
N1A N1
E1
E2
E1
E2
NEUTRAL
CONNECTION
INSIDE
SWITCH
CIRCUIT 14
E2
E2 CIRCUIT 13
CIRCUIT 10
CIRCUIT 9
CIRCUIT 6
CIRCUIT 5
CIRCUIT 2
T1 CIRCUIT 1
T2 CIRCUIT 3
CIRCUIT 4
CIRCUIT 7
CIRCUIT 8
CIRCUIT 11
CIRCUIT 12
CIRCUIT 15
CIRCUIT 16
LC
Section 3.2
Operational Analysis
194
CONTROL
TRANSFER
23
LOAD SENSING
T1
120VAC
OUTPUT
N2
UTILITY
SENSING
240VAC
N1 OUTPUT
BLACK
RED
NEUTRAL (WHITE)
GROUND (GREEN)
GROUND (GREEN)
NEUTRAL (WHITE)
240VAC TO
RED (MAIN 2) MAIN DISTRIBUTION
PANEL
BLACK (MAIN 1)
TS TO
GENERATOR
CONTROL
PANEL
TO
OUTPUT
GENERATOR
Page 65