A heating element is a device that is used to produce radiant heat energy in various types of heating appliances. A heating element consists of a metal wire that is heated when an electric current is passed through it. The material of the heating element resists the flow of the electric current and heats up. This process converts electric energy into heat energy.
The heat generating capacity of a heater is in accordance with Ohm's law and is determined by the length and the diameter of the wire. The smaller the diameter and longer the length of wire, the more heat will be generated. Thus, heating elements are made of a very thin wire that is coiled so as to increase the length in as tight an area as possible. This coil is then shaped per requirement, like open ribbon or an enclosed coil, etc.
Industrial heating elements are made of special materials so they are able to withstand very high temperatures and corrosive gases such as nitrogen. Many heating elements are made of a non-magnetic nickel and chrome alloy known as nichrome, however other materials are also used such as platinum and silicon carbide. Heating elements are present in all types of electric heating appliances such as hair dryers, clothes dryers, electric water heaters, coffee makers, portable heaters, toasters and industrial furnaces.
Radiant space heaters use a quartz incandescent bulb in which a wire filament is heated by an electrical current as the source of heat. A rear window defroster in an automobile is generally heated by a positive thermal coefficient (PTC) ceramic. A PTC ceramic possesses a self regulating thermostat as the current flows when the unit is cool, but doesn’t flow when the unit heats up. This process will prevent the element from overheating.
As with all types of electrical devices and heaters, you must be very careful when working with heating elements. Remember that heating elements conduct electricity, so working with them can be dangerous. When working with heating elements make sure there is no electrical power going to the heating element before you begin. Don’t just turn off the appliance make sure you also unplug it from the electrical outlet. If the appliance is wired to a circuit then make sure you also disconnect the circuit. You can use a multimeter to test the conductivity of a heating element. If you get a reading of infinity it means you have a faulty heating element and it should be replaced.