Electrical System Description - Komatsu 930E-2 Shop Manual

ELECTRICAL SYSTEM DESCRIPTION

The Komatsu Truck utilizes a 24VDC electrical system
which supplies power for all non-propulsion electrical
components. The 24VDC is supplied by pairs of 12 volt
storage batteries wired in series. The batteries are a
lead-acid type, each containing six 2-volt cells. With
keyswitch ON and engine not operating, power is
supplied by batteries. When the engine is operating,
electrical power (non-propulsion) is supplied by a 24
volt alternator.
BATTERY
During operation, the storage batteries function as an
electrochemical device for converting chemical energy
into the electrical energy required for operating the
accessories when the engine is shut down.
Lead-acid storage batteries contain sulphuric
acid, which if handled improperly may cause seri-
ous burns on skin or other serious injuries to
personnel. Wear protective gloves, aprons and eye
protection when handling and servicing lead–acid
storage batteries. See the precautions in Section
"A" of this manual to insure proper handling of
batteries and accidents involving sulphuric acid.
Maintenance and Service
The electrolyte level of each cell should be checked at
the interval specified in the Lubrication and Service
Section "P", and water added if necessary. The proper
⁄ ⁄
3 1
level to maintain is –
8 2
plates. To insure maximum battery life, use only dis-
tilled water or water recommended by the battery
manufacturer. After adding water in freezing weather,
operate the engine for at least 30 minutes to thoroughly
mix the electrolyte.
DO NOT SMOKE or allow flame around a dead
battery or during the recharging operation. The
expelled gas from a dead cell or charging battery
is extremely explosive.
M13002 2/99
24VDC ELECTRIC SUPPLY SYSTEM
in. (10-13 mm) above the
24VDC Electric Supply System
with 220 Amp. Niehoff Alternator
Excessive consumption of water indicates leakage or
overcharging. Normal water usage for a unit operating
eight hours per day is about one to two ounces per cell
per month. For heavy duty operation (24 hour) normal
consumption should run about one to two ounces per
cell per week. Any appreciable increase over these
figures should be considered a danger signal. No
water consumption may indicate undercharging or sul-
phated plates.
Troubleshooting
Two most common troubles that occur in the charging
system are undercharging and overcharging of the
truck's batteries.
An undercharged battery is incapable of providing
sufficient power to the truck's electrical system.
Some possible causes for an undercharged battery
are:
Sulfated battery plates
Loose or corroded battery connections
Defective wire in electrical system
Loose alternator drive belt
A defective alternator
A defective battery equalizer
Overcharging, which causes battery overheating, is
first indicated by excessive use of water. If allowed to
continue, cell covers will push up at the positive ends
and in extreme cases the battery container will become
distorted and cracked.
Leakage can be detected by continual wetness of the
battery or excessive corrosion of the terminals, battery
carrier and surrounding area. (A slight amount of cor-
rosion is normal in lead–acid batteries). Inspect the
case, covers and sealing compound for holes, cracks
or other signs of leakage. Check battery hold down
connections to make sure the tension is not great
enough to crack the battery, or loose enough to allow
vibration to open the seams. A leaking battery should
be replaced.
To remove corrosion, clean the battery with a solution
of ordinary baking soda and a stiff, non-wire brush and
flush with clean water. Make sure none of the soda
solution is allowed into the battery cells. Dry off battery.
Be sure terminals are clean and tight. Clean terminals
are very important in a voltage regulated system.
M13-1