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amperes armature blow-off carbon brushes cause cell circulation coal coiled conductor combustion compound-wound conductor connected copper core cubic foot current flowing cylinder deflection diameter difference of potential direct current direct-current direction drum dynamo electricity electromotive force equal example external circuit field coils field magnets flue furnace galvanometer gases Hence horsepower hydrogen input insulation internal resistance iron joint latent heat lever lines of force load loss machine magnetic field motor number of lines Ohm's law ohms open circuit output pass pipe placed plate pole pieces position pound of water pounds per square quantity of heat residual magnetism reversed rheostat ring riveted rotated safety valve segments series coils series dynamo shaft shell short-circuited shown in Fig shunt coils shunt field space sparking speed square inch steam pressure strength of current substances surface temperature terminals tion tubes ture voltage voltmeter volts water-tube boiler watts weight wire
Σελίδα 27 - As a unit of current, the international ampere, which is onetenth of the unit of current of the cgs system of electromagnetic units, and which is represented sufficiently well for practical use by the unvarying current which, when passed through a solution of nitrate of silver in water, and in accordance with accompanying specifications, deposits silver at the rate of 0.001118 of a gramme per second.
Σελίδα 7 - Strength of the induced EMF The strength of an induced EMF is found to depend simply upon the number of lines of force cut per second by the conductor, or, in the case of a coil, upon the rate of change in the number of lines of force which pass through the coil. The strength of the current which flows is then given by Ohm's law ; that is, it is equal to the induced EMF divided by the resistance of the circuit.
Σελίδα 76 - It overcomes the attractive forces that tend to hold the molecules of a substance together, and thus changes it from a solid to a liquid or from a liquid to a gas, according to the state it was in when the heat was applied.
Σελίδα 48 - It is further supposed, by chemists, that at a given pressure and temperature equal volumes of all gases, whether simple or compound, contain the same number of molecules. Thus, a cubic foot of hydrogen, a cubic foot of air, a cubic foot of steam, all contain the same number of molecules at the same temperature and pressure.
Σελίδα 133 - Avogadro's celebrated enunciation of the theorem that equal volumes of gases at the same pressure and temperature contain equal numbers of molecules is sufficient authority for the principle of equal molal volumes.
Σελίδα 2 - If there is a stop-valve between the valve and boiler, have it removed or arranged so that it cannot be shut. Take care that the valve does not become corroded and stick to its seat. It is a good plan to frequently lift the valve from the seat and see whether or not it works freely. Do not overload the valve or increase the tension of the spring, and take care that it is not done by others. When the blow-off pressure is fixed, the weights are often locked in position by the boiler inspector and should...
Σελίδα 77 - The unit quantity of heat is the quantity required to raise the temperature of a pound of water from 62° to 63°...
Σελίδα 7 - A good plan is to send the current in the direction of the movement of the hands of a watch around its face, that is, pick out some person to represent the figure XII, and then start the current moving in the direction of "right
Σελίδα 13 - If a steam gauge shows an error of more than five pounds, it will be condemned by most boiler inspectors. Steam gauges should be taken off at least once a month and the connecting pipe cleared by blowing steam through it. When the gauge is off, see that the hole in the nipple is perfectly clear. 25. Number of Gauges Used. — Good practice demands that one steam gauge should be attached to each boiler where there is more than one boiler used. In some regions, however, it is not uncommon to see one...