Basic Electrical Installation Work

| Kategorie: Kniha  |

Strana 111 z 399

Jak získat tento dokument?






Poznámky redaktora
4.1 the last chapter looked the atomic structure materials. Alloy alloy mixture two more metals.Basic Electrical Installation Work 100 Properties conductors and insulators In Fig. It good insulator, but degrades and becomes brittle when exposed to sunlight. These electrons can easily become ‘free electrons’ which allows heat and electricity pass easily through the material. Definition Non-ferrous Metals which not con- tain iron are called non-ferrous. An insulator material, usually non-metal, which the electrons are very firmly bound the nucleus and, therefore, will not allow heat elec- tricity pass through it. Synthetic rubber manufactured, opposed being produced natu- rally. Thermosetting polymers Once heated and formed, products made from thermosetting polymers are fixed rigidly. Ferrous word used describe all metals which the main constituent is iron. Definition An insulator material, usually a non metal, which the electrons are very firmly bound the nucleus and, therefore, will not allow heat elec- tricity pass through it. Copper, aluminium, tin, lead, zinc and brass are examples non-ferrous metals. The word ‘ferrous’ comes from the Latin word ferrum meaning iron. Synthetic artificial rubber carefully manufactured have all the . Ferrous metals have magnetic properties. Plug tops, socket outlets and switch plates are made from this material. Non-ferrous Metals which not contain iron are called non-ferrous. Most corrosion takes place when metal contact with moisture (see also mild steel and zinc). Thermoplastic polymers These may repeatedly warmed and cooled without appreciable changes occurring the properties the material. Polyvinylchloride (PVC) used for cable insulation thermo- plastic polymer. Brass alloy cop- per and zinc, usually the ratio 70–30% 60–40%. They are non-magnetic and resist rusting. Definition A conductor material, usually a metal, which the electrons are loosely bound the central nucleus. Corrosion The destruction metal chemical action. They have a flexible quality when operated maximum temperature 70°C but should not flexed when the air temperature near 0°C, otherwise they may crack. What makes them differ- ent materials the way which the atoms and electrons are arranged and how strongly the electrons are attracted the atoms. Rubber tough elastic substance made from the sap tropical plants. All materials are made atoms and electrons. Definition Corrosion The destruction metal by chemical action. Definition Ferrous word used describe all metals which the main constituent is iron. Let now define the terms and properties some the materials used in the electrotechnical industry. Definition Polyvinylchloride (PVC) used for cable insulation thermoplastic polymer. Definition Thermoplastic polymers These may be repeatedly warmed and cooled with- out appreciable changes occurring in the properties the material. A conductor material, usually metal, which the electrons are loosely bound the central nucleus. Cast iron, wrought iron and steel are all ferrous metals. Definition Alloy alloy mixture two or more metals. They are good insulators, but give off toxic fumes when burned. These electrons can easily become ‘free electrons’ which allows heat and electricity pass easily through the material