20-06-2012, 05:38 PM
VARIABLE FREQUENCY DRIVES
VARIABLE FREQUENCY DRIVES .docx (Size: 468.56 KB / Downloads: 57)
INTRODUCTION
Liquefied Petroleum Gas (LPG/CNG) in one the most widely used alternative fuel all over the world for over 40 years. It powers more than 7 million vehicles in various countries due to its various environmental advantages.
Automotive LPG/CNG is a clean – burning, high octane number, environmental friendly transportation fuel with its proven success. High octane number ensures virtually no sacrifice in power. LPG/CNG under moderate pressure and reduced temperature can be stored in liquefied form.
AUTO LPG/CNG/CNG – AN ENVIRONMENTAL FRIENDLY FUEL
• Clean efficient combustion.
• Among the lowest life-cycle greenhouse gas emissions of all commercially available fuels.
• Low sulphur content.
• High Octane number.
• Easy to transport.
• Faster refueling time as compared to other alternative fuels.
• Better anti – knocking properties than petrol. No modification on Engine.
• Very low emissions on carbon monoxide (CO), nitrogen oxide (NOx) and un-burned hydrocarbons.
COMMERCIAL ADVANTAGES
LPG/CNG fuel is much cheaper than petrol, saving can be between 45% to 50% on fuel costs as against petrol. This can vary with the petrol and LPG/CNG prices.
LPG/CNG has an anti knocking power which is comparable with Gasoline and superior to Diesel.
The oil drain period of car running on Auto LPG/CNG will increase and it will also extend the life of spark plug as Auto LPG/CNG is a clean fuel.
Adulteration or spilling or theft is not responsible.
LPG/CNG reaches the engine in pure form resulting in an improved air / fuel mixture and enables refined combustion.
There is hardly any discharge of CO (Carbon mono- oxide) as compared to petrol and diesel since the exhaust fumes contains less harmful substance.
Proof of principle
The conversion of electrical energy into mechanical energy by electromagnetic means was demonstrated by the British scientist Michael Faraday in 1821. A free-hanging wire was dipped into a pool of mercury, on which a permanent magnet was placed. When a current was passed through the wire, the wire rotated around the magnet, showing that the current gave rise to a close circular magnetic field around the wire. This motor is often demonstrated in school physics classes, butbrine (salt water) is sometimes used in place of the toxic mercury. This is the simplest form of a class of devices called homopolar motors. A later refinement is the Barlow's wheel. These were demonstration devices only, unsuited to practical applications due to their primitive construction.
Terminology
In an electric motor the moving part is called the rotor, and the part that stands still is called the stator. Magnetic fields are produced on poles, and these can be salient poles where they are driven by windings of electrical wire. A shaded pole is used in some motors and contains an inductor to delay the phase of the magnetic field for that pole.
A commutator is a device for varying the direction of flow of current to coils depending on the angle of rotor.