. A text-book of radiology . bars as there are coils on the armature. Thebeginning of one coil and the end of the coil just pre-ceding it are joined together, and the two attached to acommutator bar. Two brushes of copper gauze or carbonare arranged to touch the commutator at opposite ends ofa diameter; and as the armature is revolved the com- 20 TEXT-BOOK OF RADIOLOGY. mutator bars pass in succession under the brushes whichcollect the current from them. Most dynamos which havea commutator are arranged so that the whole or part ofthe current generated in the armature passes round thefield magn
. A text-book of radiology . bars as there are coils on the armature. Thebeginning of one coil and the end of the coil just pre-ceding it are joined together, and the two attached to acommutator bar. Two brushes of copper gauze or carbonare arranged to touch the commutator at opposite ends ofa diameter; and as the armature is revolved the com- 20 TEXT-BOOK OF RADIOLOGY. mutator bars pass in succession under the brushes whichcollect the current from them. Most dynamos which havea commutator are arranged so that the whole or part ofthe current generated in the armature passes round thefield magnet, and are thus self-exciting. The iron of thefield magnet always retains a small amount of permanentmagnetism. This is sufficient to give rise to a smallinitial current in the armature, which circulating roundthe field magnet coils gives rise to a stronger current inthe armature, and so on, until the full power of themachine is attained. If an alternating current isrequired, the armature winding is tapped at diametrically. RSS S£Nl£S WOUND DYNAMO Fig. 6.
Size: 1426px × 1752px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidtextbookofra, bookyear1915
