A Compendium of Electrical Components

The tangle of wires and other electrical parts that confronts anyone who opens an appliance may seem bewildering at first glance. But with the help of this glossary, even a novice should quickly learn to recognize the components and diagnose their malfunctions.

In general, electrical parts fall into two groups those that perform tasks and those that make decisions. The "workers" include heating elements, which convert electrical energy into heat; solenoids, which use electromagnetism to move parts; and motors, which develop electromagnetism to spin a shaft.

The decision-making parts include the many switches that govern the flow of current. These can be activated in a number of ways manually, mechanically, by heat, by pressure, or by magnetism.

The first step in diagnosing an electrical malfunction is to interpret the sensory clues that the appliance provides. A nonheating wire that is hot to the touch, a switch terminal that is charred, a burning odor, a screeching, chattering motor all are certain signs of trouble. Disconnect the appliance from its power source at once and make an orderly exploration with a continuity tester or a mulititester before you use the machine again.

Once you have located the defective part, replace it with a new one made for exactly the same wattage, voltage or amperage. These ratings are usually stamped on the body of the component. If you have any doubts, take along the old part when you go to buy its replacement.

Replacing electrical components is normally a straightforward job.If you choose to solder the connections a procedure still favored by many professionals you will need a 25- to 50-watt soldering iron, a spool of rosin core 60-40 solder, and a long-nosed soldering clamp to keep your hands free for the job.

Wires Tailored to the Tasks

Wires and power cords. The wires used in appliances come in a range of diameters-referred to as gauges-numbered from 10 to 20 in order of decreasing thickness. They almost always consist of thin copper filaments combined into a single strand and insulated with a sheathing of thermoplastic or heat-resistant vinyl. The combined filaments make the wire flexible and tough In high-heat applications, such as the connections to a heating element, the sheathing may be asbestos and the copper wire may be nickel- plated to prevent corrosion and to resist melting.

For internal connections in most appliances, single small-gauge wires are used. Such wires come in a variety of colors, sometimes striped, to make them easier to trace along a circuit. To bring power into appliances, wires are combined into three kinds of power cords. For light-duty applications lamp cord, or zip cord, is used; this is a double strand of No. 18 or No. 16 wire. On newer zip cords the insulation of one line may be ridged or textured to identify the hot wire carrying current to the appliance. Heater cord, used to carry power to heating appliances, is a double-strand cord insulated with asbestos or heavy rubber. The third type of cord, used on appliances that are individually grounded for safety such as electric clothes dryers and ovens is a heavy duty three-strand cord of No.12 to No. 10 wire. The hot wire is ridged or black, the neutral is white, the green wire is connected to the machine's ground terminal.

Any single-strand wire can be tested for continuity with a continuity tester connected to the two ends of the wire. Visual signs of trouble are burns or broken insulation at the ends of a wire or cord. Or you may be able to smell the burning insulation of a defective wire.