
SEBU8219-01 21
Safety Section
Electrical System
i02106213
Electrical System
SMCS Code: 1000; 1400
Never disconne
ct any charging unit circuit or battery
circuit cable from the battery when the charging unit
is operating. A spark can cause the combustible
gases that are
produced by some batteries to ignite.
To help prevent sparks from igniting combustible
gases that are
produced by some batteries, the
negative “−” jump start cable should be connected
last from the external power source to the negative
“−” terminal
of the starting motor. If the starting motor
is not equipped with a negative “−” terminal, connect
thejumpstartcabletotheengineblock.
Check the electrical wires daily for wires that are
loose or frayed. Tighten all loose electrical wires
before the e
ngine is started. Repair all frayed
electrical wires before the engine is started. See
the Operation and Maintenance Manual for specific
starting i
nstructions.
Grounding
Practices
Proper grounding for the engine electrical system
is necessa
ry for optimum engine performance
and reliability. Improper grounding will result in
uncontrolled electrical circuit paths and in unreliable
electrica
l circuit paths.
Uncontrolled electrical circuit paths can result in
damage to
main bearings, to crankshaft bearing
journal surfaces, and to aluminum components.
Engines t
hat are installed without engine-to-frame
ground straps can be damaged by electrical
discharge.
To ensure that the engine and the engine electrical
systems function properly, an engine-to-frame ground
strap wi
th a direct path to the battery must be used.
This path may be provided by way of a starting motor
ground, a starting motor ground to the frame, or a
direct e
ngine ground to the frame.
All grounds should be tight and free of corrosion. The
engine a
lternator must be grounded to the negative
“-” battery terminal with a wire that is adequate to
handle the full charging current of the alternator.
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Generator Isolating for
Maintenance
SMCS Code: 4450
When you service an electric power generation set
or when you repair an electric power generation set,
follow t he pro
cedure below:
1. Stop the engine.
g00104545
Illustration 19
2. Attach a “DO NOT OPERATE” or similar warning
tagtotheengineprimemoverstartingcircuit.
Disconnect the engine starting circuit.
3. Disconnect the generator from the distribution
system.
4. Lock out the circuit breaker. Attach a “DO NOT
OPERATE” or similar warning tag to the circuit
breaker. Refer to the electrical diagram. Verify that
all points of possible reverse power flow have
been locked out.
5. For the following circuitry, remove the
transformer’s fuses :
•
power
•
sensing
•
control
6. Attach a “DO NOT OPERATE” or similar warning
tag to the generator excitation controls.
7. Remove the cover of the generator’s terminal box.
8. Use an audio/visual proximity tester in order to
verify that the generator is de-energized. This
tester must be insulated for the proper voltage
rating. Follow all guidelines in order to verify that
the tester is operational.