Electrical ampere

Explanations for Table 2 The yields given in column 5 refer to the % conversion of CH3MgCl to Pb(CH3)4, if not stated otherwise, after a quantity of electricity (ampere hour (A h)) is applied. The polyethers used in the solvent system of the Grignard solution are abbreviated as follows ... 

An eunmeter, reading to 1 5-2 0 amperes, sho dd be placed in the circuit, t Supplied by Zenith Electric Ltd. j Supplied by Sunvic Controla Ltd. 

Electric current ampere A Magnitude of the current that, when flowing through each of two straight parallel conductors of infinite length, of negligible cross-section, separated by 1 meter in a vacuum, results in a force between the two wires of 2 X 10 newton per meter of length. 

Resistivity/Conductivity. The resistivity or specific resistance of a material is the electric resistance offered by an element of the material having unit length and unit cross-sectional area. The current iatensity is proportional to the voltage across its path, and is iaversely proportional to resistance. This relationship is expressed by Ohm s law, where I = current ia amperes, E = poteatial ia volts, and R = resistance ia ohms. 

Busbars. Fitting the tank for d-c power is usually accompHshed usiag round copper busbars, both for supporting the anodes and the work or cathodes. Size of the copper bus is determined by the amount of current flow expected 1000 amperes requires about 6.5 cm of cross-sectional area. The bus is iasulated from the tank, and any other sources of grounding, and coimected to the d-c power supply. Shorter distances from the tank as well as fewer electrical connections keeps the voltage drop to a minimum. 

The submitters used a transformer purchased from the Franklin Transformer Company, Minneapolis, Minnesota, for 25-30. It was provided with taps so that secondary voltages of 5500, 6600, 7700, 8800, 9900, and 11,000 could be obtained. These transformers do not always deliver the rated voltage and hence should be calibrated by actual measurement. The checkers used a luminous tube transformer obtained from the Jefferson Electric Company, Bellwood, Illinois, Cat. No. 721-411. Cap. 825 VA. Primary 115 V.A.C. 60 cycles. Secondary 15,000 V. 60 M.A. Price 19.60. The variable transformer used to regulate the voltage should be rated at 7.5 amperes and may be a Varitran, Adjustavolt, or Variac. 

Protection currents of a few amperes are needed for the cathodic protection of assemblies of storage tanks or refuelling stations. In this case, electrical contact with grounded installations is the main problem. For cathodic protection, these contacts must be located and electrically separated. If this is not possible, then local cathodic protection should be installed (see Chapter 12). 

It is usual these days to express all physical quantities in the system of units referred to as the Systeme International, SI for short. The International Unions of Pure and Applied Physics, and of Pure and Applied Chemistry both recommend SI units. The units are based on the metre, kilogram, second and the ampere as the fundamental units of length, mass, time and electric current. (There are three other fundamental units in SI, the kelvin, mole and candela which are the units of thermodynamic temperature, amount of substance and luminous intensity, respectively.)... 

Other SI electrical units are determined from the first four via the fundamental constants eo and tiQ, the permittivity and permeability of free space respectively. The ampere is defined in terms of the force between two straight parallel infinitely long conductors placed a metre apart, and once this has been defined the coulomb must be such that one coulomb per second passes along a conductor if it is carrying a current of one ampere. 

In 1820 Hans Christian Oersted discovered electromagnetism. A report of Oersted s work was delivered before a sceptical meeting of the Academic dcs Sciences held on September 4, 1820. Oersted s work was contrary to established ideas, based on Coulomb s work of the 1780s, that there could not be any interaction between electricity and magnetism. Ampere however, immediately accepted Oersted s discovery, and set to work, reading his first paper on the subject to the Academie on September 18, 1820. 

In 1821 Michael Faraday sent Ampere details of his memoir on rotary effects, provoking Ampere to consider why linear conductors tended to follow circular paths. Ampere built a device where a conductor rotated around a permanent magnet, and in 1822 used electric currents to make a bar magnet spin. Ampere spent the years from 1821 to 1825 investigating the relationship between the phenomena and devising a mathematical model, publishing his results in 1827. Ampere described the laws of action of electric currents and presented a mathematical formula for the force between two currents. However, not everyone accepted the electrodynamic molecule theory for the electrodynamic molecule. Faraday felt there was no evidence for Ampere s assumptions and even in France the electrodynamic molecule was viewed with skepticism. It was accepted, however, by Wilhelm Weber and became the basis of his theory of electromagnetism. 

The quantity of electric charge is measured m coulombs, and the unit of electric current—the number of coulombs per second that go past any point— is the ampere (A), named after French physicist Andre Marie Ampere ... 

An important property of this or any electrical circuit is the rate that charge moves past a place in the circuit (e.g., out from or into a battery terminal). The electrical current (I) is defined to be the charge (Q) that flows, divided by the time (t) required for the flow I = Q/t. In S.I. units the current (I) is in amperes (A). 

See also Ampere, Andre-Marie Clausius, Rudolf Julius Emmanuel Electricity Electricity, History of Faraday, Michael Gibbs, Josiah Willard Magnetism and Magnets Molecular Energy Oersted, Hans Christian Thomson, William. 

For one minute, one horsepower will lift 33,000 pounds one foot, or as a unit of power, this equals a rate of 33,000 foot-pounds of work per minute, or 550 foot-pounds per second. One horsepower equals 746 watts of power. The resistance to flow of electrical current through a wire or conductor is termed an ohm. One ohm is the amount of resistance in a wire through which one ampere of current flows under one volt of electrical pressure. Useful relationships are ... 

Filectnc charge or qwmltty Q, expressed in units of coulombs, is the amount of electricity that passes any section of an electric circuit in one s by a current of one ampere coulomb is the charge of 6 24 x 10" electrons. 

Power factor in an alternating current circuit is defined as the ratio of actual circuit power in watts (W) to the apparent power in voltage amperes (VA). The need for correction arises from fact that the majority of A.C. electrical loads take from the supply a lagging quadruple current (voltage amperes reactive, var) and thus operates at a lagging power factor due to the reactive (rather than capacitive) nature of their construction. 

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