Applications of Carbon Materials in Electrical Engineering
Carbon, in various forms and in combination of other materials, is widely used in electrical engineering. Electrical carbon materials are manufactured from graphite and other forms of carbon.Carbon is having following applications in Electrical Engineering-
- For making filament of incandescent lamp
- For making electrical contacts
- For making resistors
- For making brushes for electrical machines such as DC machines, alternators.
- For making battery cell elements
- For making carbon electrodes for electric furnaces
- Arc lighting and welding electrodes
- For making component for vacuum valves and tubes
- For makings parts for telecommunication equipment.
Carbon Use for Making Filament of Incandescent lampCarbon is used with inert gas medium for making filament for incandescent lamp. Resistivity of carbon is about 1000-7000 µΩ -cm and melting point is about 3500oC. Which make it suitable for making filament for Incandescent lamp. Commercial efficiency of carbon filament lamp is 4.5 lumens per watts or 3.5 watts per candle power. Carbon is having blackening effect in incandescent lamp. To prevent this blackening of bulb, the working temperature is limited up to 1800oC.
Carbon Use for Making Electrical ContactsCarbon is used as fiber formed from polymers by pyrolysis. Carbon fibers shows an unusual mechanical strength under a tensile load. These carbon fibers are used to increase the mechanical strength of electrical contacts which are subject to under compressive or tensile loads during operation. These carbon fibers also reduce the wear and tear of electrical contacts. Moreover, carbon being a conductor of electricity, contributes for carrying current passing through electrical contact in terms it reduces the contact resistance.
Carbon Use for Making ResistorsHigh resistivity, high melting point and low temperature coefficient of resistance make the carbon suitable for manufacturing resistors. Resistors made of carbon are widely used in electronic circuits.
Carbon Use for Making Brushes for Electrical DC Machines and AlternatorsGraphite Carbon is very much suitable for making brushes for large rating DC machines and alternators. Brushes made graphite carbon are having following advantages –
- Graphite Carbon brushes are having high contact resistance. This high resistance of graphite carbon brushes helps to improve commutation.
- High thermal stability – which make them suitable to withstands at high temperature developed due friction during operation of rotating machine.
- Self-lubrication between stationary brushes and rotating commutator or slip rings. Which reduces the wear and tear of commutator or slip rings.