Magnetism without magnets
Article Abstract:
Modern power and communications electrical engineering is based on natural laws and forces between electric charges and magnetic poles. Early scientists who rubbed fur on amber or glass rods to make them attract bits of straw and paper confused electricity and magnetic power, which was rumored to be lost when the rods were rubbed with garlic. In 1733 in Paris, Charles Dufay inferred the existence of vitreous and resinous electricity, and in 1785 Charles Coulomb stated in the first quantitative law of electricity that the force of attraction or repulsion is inversely proportional to the square of the objects' distance. In 1800, Alessandro Volta made the first continuous electric current battery, but electric and magnetic forces remained confusing until Hans Christian Oersted in 1820 observed the generation of a magnetic field with a current. Andre Marie Ampere then demonstrated the right-hand rule, created a device he called the solenoid and coined the phenomena electrodynamics.
Publication Name: IEEE Spectrum
Subject: Engineering and manufacturing industries
ISSN: 0018-9235
Year: 1991
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Varying speed without the hazards
Article Abstract:
Various safety regulations have to be observed when installing electric motors into atmospheres that have flammable gas, liquid or vapour because any spark may cause a fire. Some atmospheres, known as Zone 1, have constant gas so electric motors cannot be fitted at all. Atmospheres known as Zone 1 and Zone 2 have gas for varying periods of time and these can have motors so long as there is no risk of sparks or of the motor surface getting hot because this can cause the gas to ignite. Motors are often installed outdoors and they are hosed down.
Publication Name: Eureka
Subject: Engineering and manufacturing industries
ISSN: 0261-2097
Year: 1999
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Stripping away PVC: could the electrical industry survive without pvc? Greenpeace thinks it could and presents compelling arguments why it should
Article Abstract:
Greenpeace is calling on the entire construction industry to stop using pvc due to the amount of toxic waste produced during its manufacture. The electrical industry uses pvc for cable insulation and enclosures, but other materials available include nylon, steel and new 'high tech' plastics. Greenpeace believes that pvc could be gradually phased out and that cross-linked polyethylene or ethylene propylene rubber could be used for cable insulation.
Publication Name: Electrical Contractor
Subject: Engineering and manufacturing industries
ISSN: 0308-7174
Year: 1997
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