. The principles and practice of roentgenological technique . T--\BLE I RECTIFICATION OF ALTERNATING CURRENTS 19 The direct current is generally indicatedby a straight line. As a rule the direct currentis supplied from a three wire system, and gen-erated by two similar dynamos connected inseries. This makes both a current of 110 and220 volts, d. c, available depending uponwhether an inner and outer lead, or both outerleads are used. In alternating current supply the three wiresystem is also utilized in making e
. The principles and practice of roentgenological technique . T--\BLE I RECTIFICATION OF ALTERNATING CURRENTS 19 The direct current is generally indicatedby a straight line. As a rule the direct currentis supplied from a three wire system, and gen-erated by two similar dynamos connected inseries. This makes both a current of 110 and220 volts, d. c, available depending uponwhether an inner and outer lead, or both outerleads are used. In alternating current supply the three wiresystem is also utilized in making either 220a. c. or 110 a. c. available. In arranging for standard installations it iswell to provide a circuit of sufficient capacityto carry from 75 to 100 amperes without over-loading, overheating or drop in voltage. Theline drop at the highest current should notexceed 3 per cent. If essential the low-tension, alternatingcurrent may be changed into the direct. Thisis done by; 1. A rotary converter. 2. A mercury vapor lamp rectifier. 3. Chemical Fig. 10.—Diagram of a simple converter. Such anapparatus is necessary for converting alternat-ing currents into direct. In the above diagramthe rotary converter has both the simple com-mutator to collect the continuous current anda pair of slip rings for the alternating may act as a motor if supplied by either cur-rent or if driven mechanically, which may gen-erate both currents at the same time. The ar-matures are wound like a continuous currentdynamo but there is provided at either end ofthe shaft two or more slip rings, connected tosuitable points on the winding. 1. For rectification of an alternating currentby means of a rotary, the motor must be de-signed for the frequency of the rotary converters have armatures woundexactly like those of a continuous current dy-namo but at the other end of the shaft are slip rings. Supplied with alternating currentthe machine operates as a synchronous motor,th
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectradiogr, bookyear1920
