. The Street railway journal . turns at all points. The mica is protected bya sufficient amount of fibrous material to insure against de-terioration, due to mechanical vibration. This fibrous materialis treated with a moisture and oil-proof compound. An insula-tion is thus formed which has fireproof material between turnsand between copper and iron at all points, and is, therefore,capal)le of withstanding very high temperature without injury. The commutator is composed of 159 rolled and hard-drawncopper bars. These bars have solid necks raised above the sur- mica of a hardness that insures its
. The Street railway journal . turns at all points. The mica is protected bya sufficient amount of fibrous material to insure against de-terioration, due to mechanical vibration. This fibrous materialis treated with a moisture and oil-proof compound. An insula-tion is thus formed which has fireproof material between turnsand between copper and iron at all points, and is, therefore,capal)le of withstanding very high temperature without injury. The commutator is composed of 159 rolled and hard-drawncopper bars. These bars have solid necks raised above the sur- mica of a hardness that insures its wearing at the same rateas copper. The mica separating the bars from the rings is1-16 in. thick, and the mica ring also separates the bars fromthe commutator spider. The wearing surface of the commuta-tor is 16% ins. in diameter and gj4 ins. long. The bars are of adepth which allows a reduction in diameter of 2 ins. The brush holders consist of two cast-brass arms, eachsecured independently to the conunutator end of the upper.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
