ARMY TM 9-6115-604-12
NAVY NAVFAC P-8-633-12
(2)
Install lightning arrester (1 ) and check mounting surface of base castings for flushness. Arrester must sit
firmly without rocking.
(3)
Discard tags and Install ground terminal cables (11) under one of the mounting bolts but over the mounting
foot of the base casting. Each lightning arrester must be grounded In this manner.
(4)
Using hexagon head screws (2), lock washers (3), and hexagonal nuts (4), secure base casting of
lightning arrester (1) to lightning arrester mount angles (8 and 9).
(5)
Discard tags and bolt cables (11) to line terminals.
4-39.
MAINTENANCE OF MAIN DISCONNECT SWITCH S120 . Main disconnect switch S120 is used to isolate any
voltage that may be available at the bus from being fed into the unit while maintenance functions are being performed.
a.
Test. See Figure 4-6.
(1)
Remove racking handle (7) from its stowage position on left side of load circuit breaker CB101.
Using racking handle, crank circuit breaker RACKING crank OUT as far as it will go.
(2)
Lock load circuit breaker CB101 kirk-key Interlock (6) and remove key.
(3)
Insert key in main disconnect switch S120 kirk-key interlock (5) and unlock. Leave key in lock.
(4)
Move main disconnect switch handle (4) to OPEN (down) position and then return handle to
CLOSED (up) position. Ensure handle moves smoothly with no binding noted.
(5)
Lock main disconnect switch S120 kirk-key interlock (5) and remove key.
(6)
Insert key In load circuit breaker CB101 kirk-key interlock (6) and unlock. Leave key in lock.
(7)
Using racking handle, crank LOAD circuit breaker RACKING crank (3) in as far as it will go. Return
racking handle to its stowage position on left side of load circuit breaker CB101.
To avoid death or injury to personnel, no electrical component will be worked on
while energized. Ensure equipment is ``tagged out" in accordance with Chapter 1,
Section III of this manual and equipment is NOT energized. Residual voltage is
present at the generator leads with the regulator turned On, reaching SEVERAL
HUNDRED VOLTS on the generator set. Proper insulation and isolation of
metering equipment must be observed when testing this generator. USE PROPER
TEST EQUIPMENT TO CHECK FOR VOLTAGE before proceeding with work.
Do not touch exposed electrical connections when circuits are energized. DC
CONTROL and UTILITY POWER CIRCUIT BREAKERS must be deenergized and
MAINTENANCE LOCKOUT switch set to MAINTENANCE before starting any
procedure.
NOTE
Main disconnect switch S120 removal or installation may require the services of two or
more persons.
b.
Remove.
(1)
Shut down the generator set in accordance with Chapter 2 of this manual.
(2)
Disconnect load cables L1, L2 L3, and L0 at the load cable bay and park on the corresponding standoffs
to ensure that the set Is Isolated from any external power source
(3)
Open lower front cabinet A compartment and remove cabinet A rear access panel. Use grounding stick to
discharge any residual voltages that may be present at the rear cabinet components. Also apply grounding
stick on switch terminals inside the front lower cabinet.
4-100
