. Practical wireless telegraphy; a complete text book for students of radio communication . former P which is of relatively high re-sistance. By electromagnetic induction, acurrent is induced in the secondary wind-ing at a pressure of 110 volts with a corre-sponding increase of current as comparedwith that flowing in the primary current may be employed convenient-ly for lighting a bank of lamps such asindicated at L. Assume the bank of lamps in this draw-ing to consist of 8 lamps connected inparallel; they will require 4 amperes of ^ in Series on 550 Volts Circuit, curre
. Practical wireless telegraphy; a complete text book for students of radio communication . former P which is of relatively high re-sistance. By electromagnetic induction, acurrent is induced in the secondary wind-ing at a pressure of 110 volts with a corre-sponding increase of current as comparedwith that flowing in the primary current may be employed convenient-ly for lighting a bank of lamps such asindicated at L. Assume the bank of lamps in this draw-ing to consist of 8 lamps connected inparallel; they will require 4 amperes of ^ in Series on 550 Volts Circuit, current and the fuses at F-1 should have capacity of 5 or 6 amperes. On the other hand, the strength of the current in the primarywinding P is relatively low and much smaller fuses will be employed to protect this circuit. When electrical energy is transferred from theprimary winding to the secondary wind-ing, certain losses due to resistance, heating of the core and magnetic leakage takeplace, hence, the total power flowing through P exceeds that taken from S. If winding S. AT IB Fig. 62—Showing Use of Step-Down Transformer. and the circuits associated therewith take 440 watts we may assume a value of 500 wattsfor the circuit P^ Since the number of watts in a given circuit = I >< E, then (assuming W - 500no ohase displacement) I = — or for winding P, I = = amperes, the approxi- E 2200 mate value of the current flowing through winding P. A one ampere fuse would thereforeprotect the primary circuit from overload. 50 PRACTICAL WIRELESS TELEGRAPHY. The installation of all types of a power or radio equipment are made in accordance withcertain definite rules or regulations which have been adopted by the National Associationof Electrical Inspectors. These rules vary slightly in different cities of the United States,but are generally in accordance with the national code. The installation of power orwireless apparatus should not be undertaken until these rules have been caref
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
