TM 5-3805-291-23-1
THEORY OF OPERATION - CONTINUED
0003 00
ENGINE - CONTINUED
12.
Engine Electrical System.
a.
Grounding Practices.
(1)
Proper engine electrical system grounding is necessary for proper engine performance and reliability.
Improper grounding will result in uncontrolled electrical circuit paths and unreliable electrical circuit
paths. Uncontrolled electrical circuit paths can result in damage to main bearings, crankshaft bearing jour-
nal surfaces, and aluminum components.
(2)
To ensure proper functioning of engine electrical systems, an engine-to-frame ground strap with direct
path to negative battery post must be used. This may be provided by way of starting motor ground, frame-
to-starting motor ground, or direct frame-to-engine ground. Engine-to-frame ground strap must be used to
connect engine grounding stud to machine frame and negative battery post. Engine must have wire
grounded to battery.
(3)
Ground wires or ground straps should be combined at ground studs that are solely for ground use. All
grounds should be tight and free of corrosion. All ground paths must be capable of carrying any likely cur-
rent faults. An AWG #0 or larger wire is recommended for grounding strap to cylinder head. Engine alter-
nator should be battery ground with a wire size capable of managing full alternator charging current.
b.
Engine electrical system has these separate circuits:
Charging
Starting
Low amperage accessories
c.
Some electrical system components are used in more than one circuit. These components are common in more than
one circuit:
Battery or batteries
Circuit breakers
Battery cables
d.
Charging circuit is in operation when engine is running. An alternator makes electricity for charging circuit. A
voltage regulator in circuit controls electrical output to keep battery at full charge. Starting circuit is activated only
when engine start switch is activated. Low amperage accessory circuit and charging circuit are connected through
ammeter. Starting circuit is not connected through ammeter.
e.
Charging System Components.
427-C1722
0003 00-17
