ARMY TM 9-6115-604-12
NAVY NAVFAC P-8-633-12
Lightning Arresters EI01. E102. and E103. Lightning arresters E101, E102, and E103 are connected between
generator set ground and generator G1 lines T1, T2, and T3, respectively. They provide a path to ground for
high voltage transients on the output lines of generator G1 and any bus the generator set may be connected to
while load circuit breaker CB101 is closed.
Main Disconnect Switch S120. Main disconnect switch S120 is a frame-mounted, three pole switch with
group-operating parts, mechanism operating assembly, and switch handle. The switch handle and the
mechanism operating assembly are linked by a drive chain. Raising the handle to the up position closes the
switch. To prevent switch opening or closure while tied to generator G1, main disconnect switch S120 is
kirk-key interlocked with load circuit breaker CB101. The interlock prevents switch handle operation unless
CB101 is racked out. Main disconnect switch S120 is directly connected to generator set output terminals L1,
L2, and L3.
Lights. Switches. and Receptacles. 120 V ac lights, switches, and receptacles are found in the control room,
engine compartment, and generator compartment. Utility power is normally used to power these circuits, but
generator G1 may be used if SET STATION POWER circuit breaker CB124 is set TM ON and the generator set
is operating. The receptacles are protected by 20 amp circuit breakers. The lighting circuits are protected by 15
amp circuit breakers. All of these circuit breakers are part of the control room distribution panel DP2 (See figure
Wiring and Harnesses. Harnesses interconnect elements of the AC electrical power generation and control
system. Refer to wiring diagrams FO4-29. All wires in the generator set have wire number markings along their
lengths. The DC and AC schematics (FO-1 and FO-2) provide functional representations of component and
circuit interconnection within the generator set.
Cable Assemblies. Cable assemblies are used to interconnect the generator set to an external bus, to other
generator sets, and to utility power. The cables and their functions are as follows:
Outgoing Power Cable Assembly Four outgoing power cable assemblies are provided, one for each phase
line of generator set output (L1, L2, and L3) and one for neutral (10). Each cable is 100 feet (30 meters)
long. Wire identification straps along the lengths of the cables identify the cables by line number.
Terminal elbows at one end of each cable are used to connect the cables to the generator set output
terminals. Each output terminal consists of a shedwell bushing which mates with the terminal elbow of an
outgoing power cable. The output terminals are labelled L1, L2 L3, and L0 so that the cables can be
properly connected. Tie-down loops on the cable grips near the elbow end of the cables allow the cables to
be hitched to a hook on the skid base while they are connected to the output terminals. The cable grips
maintain slack in the cable to prevent undue stress at the cable-to-generator set connections. At the
opposite end of each cable is a terminal lug for connecting the cables to a load bus. A stress cone kit
installed between the cable and the terminal lug relieves corona effects at this end that could weaken the
insulation electrically. At the generator set end of each cable, an 18 inch (46 cm) 12 gage insulated wire
is used to ground the shielding of the cable to the generator set housing. Shield grounding wires are also
provided near each terminal lug end for connection to the appropriate load ground terminals. Adjacent to
each output terminal is a standoff insulator assembly. Like the output terminals, these standoffs also mate
with the output terminals. These standoffs are used to park the cables when the elbows are removed
from the output terminals.
SRM Cable Assemblies J28 and J29. These cables are required for paralleling generator sets if using the
site requirement module (SRM). The cables carry control signals necessary for automatic paralleling.
Each cable is 100 feet (30 meters) long.