Basic Electrical Installation Work

| Kategorie: Kniha  |

Strana 111 z 399

Jak získat tento dokument?






Poznámky redaktora
All materials are made atoms and electrons. Synthetic artificial rubber carefully manufactured have all the . Brass alloy cop- per and zinc, usually the ratio 70–30% 60–40%. Definition Thermoplastic polymers These may be repeatedly warmed and cooled with- out appreciable changes occurring in the properties the material. Alloy alloy mixture two more metals. Thermoplastic polymers These may repeatedly warmed and cooled without appreciable changes occurring the properties the material. Definition Corrosion The destruction metal by chemical action. 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. Plug tops, socket outlets and switch plates are made from this material. Definition A conductor material, usually a metal, which the electrons are loosely bound the central nucleus. Definition Ferrous word used describe all metals which the main constituent is iron. The word ‘ferrous’ comes from the Latin word ferrum meaning iron. 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. Let now define the terms and properties some the materials used in the electrotechnical industry. They are non-magnetic and resist rusting. Cast iron, wrought iron and steel are all ferrous metals. Ferrous word used describe all metals which the main constituent is iron. What makes them differ- ent materials the way which the atoms and electrons are arranged and how strongly the electrons are attracted the atoms. Definition Alloy alloy mixture two or more metals. These electrons can easily become ‘free electrons’ which allows heat and electricity pass easily through the material. Most corrosion takes place when metal contact with moisture (see also mild steel and zinc). Synthetic rubber manufactured, opposed being produced natu- rally. Polyvinylchloride (PVC) used for cable insulation thermo- plastic polymer. They are good insulators, but give off toxic fumes when burned. Definition Polyvinylchloride (PVC) used for cable insulation thermoplastic polymer. 4. Rubber tough elastic substance made from the sap tropical plants.Basic Electrical Installation Work 100 Properties conductors and insulators In Fig. Copper, aluminium, tin, lead, zinc and brass are examples non-ferrous metals. Ferrous metals have magnetic properties. Definition Non-ferrous Metals which not con- tain iron are called non-ferrous. It good insulator, but degrades and becomes brittle when exposed to sunlight. A conductor material, usually metal, which the electrons are loosely bound the central nucleus. Non-ferrous Metals which not contain iron are called non-ferrous.1 the last chapter looked the atomic structure materials. Thermosetting polymers Once heated and formed, products made from thermosetting polymers are fixed rigidly. These electrons can easily become ‘free electrons’ which allows heat and electricity pass easily through the material. 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. Corrosion The destruction metal chemical action