. Operation of trains and station work and telegraphy . esistances of thecoils are equal, the same amount of current will flowthrough each, and each coil will give off the same amountof heat. Consequently a short coil of high-resistancewire having a small surface must necessarily operate atan excessively high temperature, in order to dissipatethe same amount of heat as the longer coil of low-re-sistance wire having a much larger surface. In this prin-ciple lies the success of the Consolidated Electric Heaters,which have a large heating surface and operate at amoderate temperature. It is claime
. Operation of trains and station work and telegraphy . esistances of thecoils are equal, the same amount of current will flowthrough each, and each coil will give off the same amountof heat. Consequently a short coil of high-resistancewire having a small surface must necessarily operate atan excessively high temperature, in order to dissipatethe same amount of heat as the longer coil of low-re-sistance wire having a much larger surface. In this prin-ciple lies the success of the Consolidated Electric Heaters,which have a large heating surface and operate at amoderate temperature. It is claimed by the manufacturers that experiencehas demonstrated that galvanized iron wire, which hasbeen specially galvanized for the purpose, makes thebest resistance coils, and that by reason of the largeradiating surface made possible by the McElroy spiralcoil construction, the wire is heated only to a moderatedegree, thus the excessive temperature to which a highresistance wire is necessarily subjected, usually resulting115 116 RULES FOR MOVEMENT OF TRAINS. in crystallization of thewire if accompanied by vi-bration, is overcome. In each heater there aretwo resistance coils placed,one above the other. Theupper coil is of greater re-sistance and consumes lesscurrent than the lower.^H The coverings of lead wires^^ to the two coils are differentgo colors, and thus may be^H easily distinguished. TheXq top coils of all the heaters^ in the car are in series, andgm the boitom coils of all theH^ heaters are in series. Thus,^p^ wherever current is used,^g heat is given out the full^^^ length of the casing ofevery heater in the car. Atthe same time this methodof wiring is said to be thesimplest and most econom-ical in time of equippingand material used. All thistype of heaters are said tosecure convenience, sim-plicity and durability. A coil for heater, show-ing resistance coil, porcelainbushings, end plates and lead fires is shown in Figure 40. V. HEATING AND LIGHTING CARS 117 .^^^ .:::^^^^
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroa, bookyear1919
