SHAFT AS-TACHOMETER DRIVE 9N1856 - Caterpillar

Introduction to Basic Electrical Components
There are many different types of components that are used in electrical circuits.Wires
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Wires are the conductors for electrical circuits. Wires are also called leads. Most wires are stranded. The stranded wires are made up of several smaller wires that are wrapped together and covered by a common insulating sheath.The following wires are found in Caterpillar machines:
Copper is the most common type of wire. Copper wires are usually stranded.
Fusible Links are circuit protection devices that are made of smaller wire than the rest of the circuit that is protected.
Twisted/Shielded Cable is a pair of small gage wires that are insulated against RFI/EMI. This cable is used for computer communication signals.
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Many wires are bound together in groups with one or more common connectors on each end. These groups are called wire harnesses. A harness may contain wires from different circuits and systems. An example would be the harness that plugs into the headlight switch assembly. The headlight switch assembly contains wires for the following lights: parking lights, taillights, high beam headlights and low beam headlights.Some harness wires are enclosed in a plastic conduit. These conduits are split lengthwise in order to allow easy access to the harness wires. Other harness wires are wrapped in tape. Clips (plastic) and clamps (metal) attach harnesses to the machine.Caterpillar electrical schematics provide wire harness locations in order to help you easily locate a specific harness on a machine. The features of Caterpillar electrical schematics will be covered later in the lesson.Wire Gage
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Electrical circuits and electronic circuits are engineered with specific size and length of conductors in order to provide paths for current flow. The size of a wire determines how much current the wire can carry. Wire sizes can be rated in two different ways. American Wire Gage (AWG) size is usually referred to as simply the gage of the wire. Wire sizes can also be rated by metric size.When you repair machine wiring or you replace machine wiring, it is necessary to use the correct size and correct length for the conductors. Illustration 3 shows the typical resistances for the various size of conductors.When you use the AWG, remember that smaller gage numbers denote larger wire sizes, and larger gage numbers denote smaller wire sizes. Metric wire sizes refer to the diameter of the wire in millimeters, so larger metric sizes translate to larger wires.Soldering
While an electrical connection might exist between two crimped wires, it might be incomplete or faulty. Soldering creates a solid and a dependable electrical connection.The soldering process depends on the molten solder that flows into all the surface imperfections of the metals in order to be soldered. When two pieces of metal are soldered together, a thin layer of solder adheres between the metals and completes the electrical connection.Solder is a mixture of tin and lead. Solder usually contains a solder flux. The function of solder flux, is to eliminate oxidation during the soldering process. Flux also lowers the surface tension of