[Electric engineering.] . Transforcner.—The operation oflamps direct from the machine is only possible when thenumber of lights on the circuit is suited to the voltage of thedynamo. This is generally not the case, and the abovearrangement is, therefore, of limited application and has 38 ELECTRIC LIGHTING. 19 been used in comparatively few cases. Instead of supplyingthe lamps directly from the machine, a considerable rangeof applied E. M. F. may be obtained by using a constant-potential transformer with its secondary coil split up into anumber of sections. The lamps are each provided with areac
[Electric engineering.] . Transforcner.—The operation oflamps direct from the machine is only possible when thenumber of lights on the circuit is suited to the voltage of thedynamo. This is generally not the case, and the abovearrangement is, therefore, of limited application and has 38 ELECTRIC LIGHTING. 19 been used in comparatively few cases. Instead of supplyingthe lamps directly from the machine, a considerable rangeof applied E. M. F. may be obtained by using a constant-potential transformer with its secondary coil split up into anumber of sections. The lamps are each provided with areactance coil, as before, but the use of the transformeradmits of a considerable range in the number of lamps thatmay be operated on a circuit; that is, the combined voltagenecessary for the lamps may be considerably different fromthat generated by the alternator. 45. Operation From Constant-Cuxrent Transform-ers.—The method that has so far been most largely usedfor the operation of series alternating-current lamps from. a_\-;_ *?—?*, .:-i A Sect/onO-Cf Fig. 21. constant-potential alternators is that in which a special trans-former is used to transform from constant potential toconstant current. This means that the transformer must § 19 ELECTRIC LIGHTING. 39 be so constructed that its secondary voltage will changeautomatically as the number of lamps is changed. Fig. 21illustrates the action of a transformer of this kind inventedby Prof. Elihu Thomson and largely used in connection withseries alternating-current lighting. 46. A A is a laminated iron core built up in the sameway as a core for an ordinary transformer. P Pis the pri-mary coil wound so as to be thin and flat and surrounding thecentral part of the core, as shown in the sectional coil is fixed in position and is attached to the linesleading to the alternator that maintains a constant or nearlyconstant pressure across the terminals of the coil. S 5 isthe secondary coil, which is also thin and flat. This c
Size: 2138px × 1169px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookidelectricengi, bookyear1902
