. Electric railway journal . ip ring a. c. motors from 1hp to 100 hp. These controllers fol-low as closely as possible in designand construction, the controllerswhich this company has been man-ufacturing for years. In fact, thewearing parts of the and are interchangeable toa large extent. These controllers are used witheither two-phase or three-phase reversing slip ring motors. Theresistance is entirely self-contained, it being necessary to con-nect only seven leads to the controller. Where heavy currentsare to be handled, cast grid resistance is employed. Unusualprec
. Electric railway journal . ip ring a. c. motors from 1hp to 100 hp. These controllers fol-low as closely as possible in designand construction, the controllerswhich this company has been man-ufacturing for years. In fact, thewearing parts of the and are interchangeable toa large extent. These controllers are used witheither two-phase or three-phase reversing slip ring motors. Theresistance is entirely self-contained, it being necessary to con-nect only seven leads to the controller. Where heavy currentsare to be handled, cast grid resistance is employed. Unusualprecautions have been taken to insure permanently satisfactoryinsulation. All contacts are mounted on a vertical slate face so that dustcannot settle between segments to cause short circuits. Allcontacts are of heavy copper and are reversible. Screws orbolts with special threads have been avoided, and so far aspossible the wearing parts have been designed to permit theirmanufacture by the user. All of these controllers are oper-. A. C. Controller 998 ELECTRIC RAILWAY JOURNAL. [Vol. XXXV. No. 23. ated by a lever motion which the manufacturers consider ad-vantageous for crane and mill service. The company also makes controllers for squirrel-cage motors and commu-tating motors. SUBSTATION COSTS IN NEW YORK INDEPENDENT HYDRAULIC JACKS The Duff Manufacturing Company, Pittsburgh, Pa., recentlyhas put on the market the hydraulic lifting jack shown in theaccompanying cut, in capacities ranging from 100 to 500 tons,with a raise from 6 in. to 12 in. It is for use in restricted areaswhere it is inconvenient to operate an ordinary jack. There aretwo main parts—the water reservoir with pump chambers andthe ram or lifting mechanism. As illustrated, these parts areseparate except for the flexible copper tubing which connectsthem. Consequently, the ram can be placed wherever there isroom for it, while the pump can be set at any distance permittedby the length of the tube. The jack can be pl
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