Hawkins Electrical Guide: Questions, Answers & Illustrations; a Progressive Course of Study for Engineers, Electricians, Students and Those Desiring to Acquire a Working Knowledge of Electricity and Its Applications; a Practical Treatise, Volúmenes5-6

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Página 1-456 - MOTOR-CONVERTER is a combination of an induction motor with a synchronous converter, the secondary of the former feeding the armature of the latter with current at some frequency other than the impressed frequency; ie, it is a synchronous converter concatenated with an induction motor.
Página 1-39 - Capacity. — The quantity of electricity which a condenser is able to store or condense is known as its electrostatic capacity. The unit of capacity is called the farad. A condenser is said to have a capacity of one farad if one coulomb of electricity is stored on each plate at a pressure of one volt between the plates. The farad being a large unit, the microfarad one millionth (0.000001 of a farad) is generally used.
Página 1-30 - ... telegraph practice. He was made a professor at Princeton in 1832, and during his experimenting then, he devised an arrangement of batteries and electromagnets embodying the principle of the telegraph relay which made possible long distance transmission. He was the first to observe magnetic self-induction, and performed important investigations in oscillating electric discharges (1842), and other electrical phenomena.
Página 1-382 - AVhen the load on a transformer is increased, the primary of the transformer automatically takes additional current and power from the supply mains in direct proportion to the load on the secondary. When the load on the secondary is reduced, for example by turning off lamps, the power taken from the supply mains by the primary coil is automatically reduced in proportion to the decrease in the load. This automatic action of the transformer is due to the balanced magnetizing action of the primary and...
Página 1-344 - Single phase fan motor with shading coils for starting. In addition to the main field coils, one tip of each pole piece is surrounded by a short circuited coil of wire or frame of copper, as indicated in the figure. This coil, or copper frame, is called a shading coil and it causes a phase difference between the pulsating flux that emanates from the main portion of each polar projection and the pulsating flux which emanates from the pole tip. thus introducing a two phase action on the armature which...
Página 1-333 - Fig. 318, which are thrown outwards by the centrifugal force when the machine reaches full speed, thus pushing the solid copper ring K, into contact with the inner ends of the commutator bars L, and thus completely short-circuiting the armature winding. At the same time barrel I, which is pushed endwise by the governor weights and which carries the short-circuiting copper ring K, pushes...
Página 1-515 - ... initial arc, and the arc thus obtained excites the cathode, giving the necessary ionized vapor, which enables the working anodes to immediately become active and the tube to start. A detailed idea of the operation of the mercury arc rectifier circuit may be obtained from Figure 3. Assume an instant when the terminal H of the supply transformer is positive, the anode A is then positive and the arc is free to flow between A and B, B being the mercury cathode. Following the direction of the arrows...
Página 1-457 - ... former feeding the armature of the latter with current at some frequency other than the impressed frequency; ie, it is a synchronous converter concatenated with an induction motor. 20 d. A...
Página 1-41 - ... proportional to the area of the plates, and inversely proportional to the distance between them, and that the capacity is (47) C = -^—^, [See note, p.
Página 1-35 - The voltage of the current and resist an ;c of the coil are of such values that when a steady current is flowing, the lamp filament is just perceptibly red. At the instant of making the circuit, the lamp will momentarily glow more brightly than when the current is steady; on breaking the circuit the lamp will momentarily flash with great brightness. In the first case, the reverse pressure, due to inductance, as indicated by arrow b, will momentarily oppose the normal pressure in the coil, so...

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