Complete workshop & service manual with electrical wiring diagrams for Komatsu W120-3 Wheel Loader. It's the same service manual used by dealers that guaranteed to be fully functional and intact without any missing page.

This Komatsu W120-3 Wheel Loader service & repair manual (including maintenance, overhaul, disassembling & assembling, adjustment, tune-up, operation, inspecting, diagnostic & troubleshooting…) is divided into different sections. Each section covers a specific component or system with detailed illustrations. A table of contents is placed at the beginning of each section. Pages are easily found by category, and each page is expandable for great detail. The printer-ready PDF documents work like a charm on all kinds of devices.

"Shop Manual (SEBM0383C01).pdf"
798 pages: Komatsu W120-3 Wheel Loader Shop Manual
SERIAL NUMBERS: 50001 and UP

EXCERPT:
ELECTRICAL SYSTEM
The electrical circuit employed in the W120-3 series tractor is a 24 volts, negative ground system. Electrical energy stored in the batteries is available upon demand to the system components. These components, which include the instruments, headlights, stop and tail lights and starting motor, are dependent upon battery energy until the engine drives the generator at a speed sufficient to carry the electrical load. Above this predetermined speed, electrical energy produced by the AC generator supplies the normal demands of the system. A portion of this energy is sent to the batteries to keep them in a state of full charge.
A regulator controls the output of the generator. By using a regulated control, electrical energy produced by the generator is supplied to the system components on
demand.
Two heavy duty twelve volt batteries, wired in series produce a 24 volts system. A battery is housed in each of the battery boxes located on the rear main frame.
Hinged tops on the battery boxes provide easy access for servicing.
The system may be divided into two circuits; the cranking circuit during engine starting and the charging circuit, supplying current to the remainder of the system when the engine is operating. In addition, the charging circuit replaces electrical energy drained from the batteries.
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