Telegraphy, Volum 23International Textbook Company, 1901 |
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adjusted alternating current aluminum ampere ampere-hours armature binding posts cable cent circular mils closed coil condenser conductivity conductors connected copper wire cores cross-arms current flowing curve dash diameter direct current distance dots dynamo earth electric electromagnet electromotive force electrostatic capacity fastened feet formula fuse gauge given gravity cells ground plate gutta percha inches inductance instruments insulation internal resistance iron wire joint lamp leakage Leclanché cell length letters lever line circuit line wire loop machine magnet main-line manhole messenger wire method mile mils Morse motor necessary number of cells number of turns office set ohms operator pike poles placed pole position pounds quadruplex receiving relay rheostat screw self-induction sending sheath shown in Fig side signals sleeve solder sounder space splice spring jack storage batteries strength switch switchboard telegraph line tensile strength terminals tion usually voltage volts wedge Western Union words zinc
Populære avsnitt
Side 70 - The electrical resistance of the wire in ohms per mile, at a temperature of 68°...
Side 1 - A circular mil is a unit of area used in expressing the cross-section of round or cylindrical wires. It is equal to the square of the diameter in mils. (c) Because the area of a round wire in circular mils is equal to the square of the diameter in mils, and because the conductivity of wires of the same material are directly proportional to their area expressed in circular mils.
Side 24 - In a paper read before the American Institute of Electrical Engineers in...
Side 63 - ... pounds per square inch. The tensile strength per square inch is taken at 50,000 pounds for 0000, 000, and 00, 55,000 pounds for 0, and 57,000 pounds for 1. 92. Mechanical Properties. — In purchasing copper wire in large quantities, certain requirements are made as to the strength and other mechanical properties of the wire. The strength of the various sizes of copper wire should be in accordance with Table 12.
Side 85 - Beaume" hydrometer scale, there is too little sulphate of zinc; when it is 30° or over, there is too much in solution, and it must be diluted. When the zincs become coated so as to interfere with the proper action of the battery, they must be taken out, scraped clean, and washed. A gravity cell can be maintained in excellent condition by keeping it on a closed circuit about 60 per cent, of the time. If kept on open circuit too long a time the solutions mix and the cell is not ready for immediate...
Side 34 - The guy stubs should conform to the same specifications as the poles regarding quality of wood, and are usually made from the parts of poles too crooked to be used as poles. For ordinary purposes, a guy stub should be not less than 8 inches in diameter at the small end, and its length from 7 to 10 feet.
Side 12 - As an increase in the current flowing in one direction through a circuit always tends to induce a current in the opposite direction, while a decrease in the current tends to induce a current in the same direction, self-induction may be said to be that property of a circuit that tends to prevent any change in the strength of a current flowing in it. Selfinduction has, therefore, been defined as the "inherent quality of an electric current that tends to impede the introduction, variation, or extinction...
Side 20 - The inductive resistance is dependent on the self-induction (ie, the electromagnetic condition of the wire) and the frequency of the alternating current. The effect of the self-induction is to retard the rise and fall of the current so that it attains its maximum later than the maximum of the alternating pressure that sets it up; and it also increases the apparent resistance to the flow of the alternating current in the circuit. Thus, if the curve M in Fig.
Side 48 - If d is in mils, the area will be in square mils. The area of ;i circle 1 mil in diameter is ^- x 1' — r square mil; and, conversely, 1 square mil = —circular mils. The area of any circle in circular mils will be equal to the area of that circle in square mils multiplied by the number of circular mils in 1 square mil; thus, the area of a circle...
Side 97 - ... hoists or elevators. Dynamotors, Fig. 33, and also motor-generator sets, are started in the same way as motors ; that is, the motor portion of the machine is connected to the circuit and operated precisely like the corresponding kind of motor. Usually the motor part is plain shunt-wound, and is supplied with current from a constant-potential circuit. It is therefore connected and started in the manner shown and described on page 40. The current generated by the dynamo portion of the dynamotor...