. The Street railway journal . any relativemotion between thecommittator bars andthe armature the periphery ofthe cummutator hubthe hard-drawn coppercommutator bars arefirmly clamped bymeans of steel endrings. The insulationbetween the bars andthe hub is made fromthe purest India mica,while that between theIjars is made from apeculiar cjuality ofsilver mica. This in-sulation IS so carefully made that in testing between the com-mutator bars and tlie Inil), the alternating pressure may bemade so high that the current will creep over the edge of the micarings, a distance of from i in.
. The Street railway journal . any relativemotion between thecommittator bars andthe armature the periphery ofthe cummutator hubthe hard-drawn coppercommutator bars arefirmly clamped bymeans of steel endrings. The insulationbetween the bars andthe hub is made fromthe purest India mica,while that between theIjars is made from apeculiar cjuality ofsilver mica. This in-sulation IS so carefully made that in testing between the com-mutator bars and tlie Inil), the alternating pressure may bemade so high that the current will creep over the edge of the micarings, a distance of from i in. to 2 ins., without puncturing. To theback end of the commutator bars flexible copper leads are riveted,extending ardically up tu and connected with the armature wind-ings. These joints are all exposed, and can be inspected at anytime, so that if repair is required it is only the work of a fewmoments. Fig. 8 shows how the commutator rings are manufactured, all inone piece, some of them being made 7 ft. or 8 ft. in diameter. It. FIG. 5.—ARMATURE CORE BEFORE WIND-ING, END PLATE REMOVED
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Keywords: ., bookcentury1800, bookdecade1880, bookidstreetrailwa, bookyear1884
