WOOD COMPENSATING VOLTMETER.

switch is open. Another part of this floor is devoted to the finishing of brass patterns for switches, single and double pole fuse boxes, arc cut-outs, switchboard are plugs, and a variety of similar work.

The Wood double pole primary fuse box shown on this page is designed with special reference to safety for the lineman and ease in inspecting and replacing a burnt-out fuse. As will be seen, the fuses are mounted on the cover in porcelain blocks and in such a way that they can be readily slid out for renewal. The very act of opening the cover breaks the circuit on both sides of the line, so that there is no danger of shock from a possible ground.

PRIMARY BRANCH SINGLE POLE FUSE BOX.

The Wood primary branch single-pole fuse-box and the manner of withdrawing the fuse block for renewal are shown on this page, the contacts being made automatically.

made which are soldered into the wire and are in turn secured to neat binding posts on the base and to the ends of the rod. Another particular feature of this machine is that the direction of the current can be reversed within the space of a few minutes without breaking a connection, which is accomplished by reversing the brush holders on the brushholder studs. The wires under the machine are encased in Interior Conduit tubing.

During the run of the machine witnessed by the writer 50 lamps were thrown on and off with barely a perceptible spark at the commutator. The machine, in fact, may be justly said to represent one of the greatest advances which has been made in arc light machinery for some time past. The Fort Wayne Corporation build arc machines from 1 up to 125 lights of 2,000 c. P. This testing room is also fitted up with racks for the testing of arc lamps. Among the latter we noticed, besides the standard single and double carbon lamps for indoor and outdoor use, a special short arc lamp, illustrated on page 558, which is designed

ARC LAMP DEPARTMENT.

VI.

The wing on the ground floor devoted to the testing of arc dynamos and arc lamps is specially arranged for the purpose, and presents, probably, as well arranged a plant of this nature as can be found anywhere. Power for testing is derived from an engine of 250 H. P., belted to overhead counter-shafting, from which power is taken by belt to the machines to be tested. While visiting the works, the writer had occasion to witness the test of the new Wood 125-light 2,000 c. P. arc machine, which was described in our last issue, and of which an illustration is given on page 563. This machine is so arranged that either pedestal can be slid out and the armature taken out and put back ready to run in 15 minutes; and all this without breaking a single electrical connection. The wires connecting the field coils are of inch round brass rod, covered with hard rubber tubing to inch when finished. This connecting link also acts as a handle for the support of the attendant while inspecting the machine. None of the wires at the coil ends is directly connected to any other wire. At these points neat copper connectors are

STACKING TRANSFORMER CORES.

for the illumination of interior spaces where the ceilings are comparatively low. These lamps are provided with short elliptical, flat carbons, whose life is as long as that of the regular round carbon type.

VII.

Ascending to the second floor of the main shop we find it devoted to the manufacture of transformers, a new design of which has recently been perfected by Mr. J. J. Wood, the electrician of the company. The transformer complete, and also taken apart showing its interior construction, is illustrated on page 552. The coils, after being wound, insulated with mica and baked, are tested to 5,000 volts alternating between primary and secondary. They are then "stacked," that is, the iron core is inserted. The shape of these cores will be seen in the illustration on page 560. Two of these punchings are placed in juxtaposition, each alternate pair breaking joints; there is, therefore, no greater thickness of iron in the centre of the core than at the outer ends. After the core is in place semicylindrical wooden pegs of maple, boiled in a special compound, are driven in to set up the coil and keep the iron core in place. This method of clamping the iron core does away with the necessity of all bolts, screws or special clamping plates. After the stacking is finished, the coil is again subjected to the 5,000 volt test; if found in good condition it is put in the iron case, the line wires soldered to it, and the case hermetically

ASSEMBLING ALTERNATING METERS.

WOOD TRANSFORMER, SHOWING VENTILATING CASE.

transformer case is provided at the top with an eye bolt, by which it can be readily lifted to the desired point. That point being reached, as, for instance, the cross arm of a pole, the transformer can then be immediately lowered to its final position and its suspension maintained by two special swivel suspension hooks. Resting on these hooks the final securing with lag screws can be done at the convenience of the linemen. For temporary work the transformer can be placed in position solely by means of these suspension hooks and be removed in the shortest possible time. The transformers are also provided with feet so that they can be stood up on the floor when desirable.

The transformer coils are wound on special machines shown on this page, provided with mechanism in the shape

WOOD TRANSFORMERS.

of a counter. This counter is set at the number of turns desired for each coil and when that number has been wound a bell announces the fact to the workman who is thus relieved of all need of that counting and keeping record, which frequently leads to errors; while on the other hand it allows a much more accurate construction than is possible where merely a given length of wire is wound, indicated by a measuring attachment. In winding the coils of the transformer, the sections of the primary and secondary are alternated.

VIII.

At the end of this floor is fitted up an elaborate testing room shown on page 561, where the transformer tests above alluded to are carried out. This room is equipped with a full complement of instruments and also with changing switches which enable the transformers of any voltage to be tested without changing any rheostat connections. Here also are tested the armatures of the alternating machines, 5,000 volts being applied between the core and coils and the same potential between coil and frame. The armature is then connected up, the commutator for the

IN THE BRASS FOUNDRY.

be used for both two and three phase currents, or, indeed, for that matter, for currents of any phase.

Another instrument which will be of special interest to managers of alternating current stations is the new Wood

As the fine wire is connected directly to the station transformer, no auxiliary transformers are required. The magnetic system of this instrument is on the repulsion principle, and, as will be noted, the scale divisions are very uniform over the entire range.

We also observed here an alternating fan motor adapted to be run on circuits of all phases, the armature consisting of a copper cylinder with an iron core as a "diverter." In one corner also, we noticed apparatus constructed for the purpose of repeating some of the Tesla high frequency experiments. We remarked here a simple method for obtaining the air blast for blowing out the spark at the air gap. This consisted of an alternating fan motor provided with a fan having 10 blades, arranged in the manner

NEW WOOD ARC DYNAMO.

compensating voltmeter, a view of which, with the cover removed, is shown on page 559. This instrument is intended to give the indicactions direct of the difference in potential at the distant end of an alternating feeder and thus to do away with compensators heretofore employed for that purpose. The fine coil is, as usual, connected across the circuit at the station; surrounding it is a single turn of heavy copper strip, in series with the line circuit and connected so as to act differentially to the fine wire coil.

As the load increases, it tends to weaken the field and thus reduces the reading of the voltmeter and in this manner gives an exact indication of the potential at the distant end. By using a variable low resistance shunt the instrument can be adjusted to any conditions of line loss.

IN THE DRAFTING DEPARTMENT.

of an undershot water wheel; with the motor revolving at 2,000 revolutions per minute the 10 blades thus give 20,000 puffs per minute and hence as many breaks at the spark gap.

The electrical equipment of the laboratory is a most excellent one. Besides a complete series of standard resistances, there are here a Weston voltmeter, Lord Kelvin's electric balances, a 500-ampere Siemens dynamometer, a Kelvin electrostatic voltmeter, tangent galvanometers, and a variety of other apparatus of like nature.

The Office Building, connected with the works by a bridge, is a two-story brick structure, 65 x 65 feet, with an attic. The ground floor is occupied by the offices of the Corporation, the book-keepers, etc. The second floor is