The regulation of the machine is a development of the methods heretofore employed by Mr. Ilochlmusen. and is very ingeniously carried out. consisting in the shifting of the brushes in conjunction with a regulating resistance, both of which are simultaneously operated by an old device originated by Mr. Hochhausen—namely, a small auxiliary motor. This motor, which is entirely hidden from view, is situated in the hub-like projection bearing on the arms which span the two pole-pieces beside the end of the armature-shaft, and which might be mistaken, except on closest scrutiny, for the bearing of the shaft. This small motor is fixed in a magnetic field. which is produced by attaching the cast-iron arms shown, to each pole-piece and bringing them together, so as to surround the armature of the sinall motor. It Might be thought for an instant tha-t such a bridging of the magnetic circuit would take a large number of the magnetic lines of force awa,y from the armature, but this has been pro vided for by mounting the cast-iron arms, not directly on the pole-pieces, but by separating the two iron surfaces by a good thickness of hard rubber, so as to make a considerable break in the magnetic circuit. The magnetism passing through the arms, therefore, is very weak, but, nevertheless, sufficiently strong to prodnce a field for the small regulating-motor, which acts with the greatest promptness. The regulation of the machine is effected in a very in genious mariner by means of a wall-regulator, which serves as a controller for the regulating motor. The method employed is very clearly shown in the diagram, Fig. 44. Here, it will be seen, .31 B are the main brushes mounted upon a rocker-arm, which is provided with a circular rack which meshes with a pinion attached to the end of the shaft of the small motor regulator. Starting from the positive terminal of the machine, P, the current is led to the binding-post 4 on the wall controller, and from there passes into the controller-magnets 31 J1. After traversing these magnets the current enters the armature A, and after pass ing through the resistance Ili goes to line and the external circuit to the neg ative terminal and main brush of the machine. It will be noted, however, that the end of the controller armature A bears against two contact-points CO, which are connected through points 2 and 3 to the brushes of the small regu lating motor on the machine. At the stone time the two latter circuits are tapped at points and 1", and con nected through German - silver resist ances 1° to the terminal 1. Now, the regulating magnet Al .J1 is so ad justed that when the normal current passes over the line, the armature A stands horizontal and makes contact with both points CO, which are fixed at the end of the lever B, The current entering the Armature A from the mag nets JIM, therefore, besides passing to line through the resist-ance has two other paths open to it through contacts CC' to the brushes of the small regulat ing motor via points 2 and 3. But it will lie remarked that tho currents in these two circuits are in the same direction, when they meet at the regulating motor opposite each other, with the result that they have no effect on the little motor, the armature of which remains stationary. It will also be noted that a part of the regulating current passes to line through and Now, if from any cause an increase of current takes place alcove the normal, the armature A of the wall-con troller is drawn down out of its horizontal position, by which action the contact at C is broken, while that mit (," is still maintained. The regulating, current now hes only one path open to it, from Cl to 2 2, etc., to the left-hand brush of the motor-regnlat or, thence through the armature to the other brush to points 3 3 and out to line through the resist ance This affords a complete and continuous path for the regulating current, end the motor armature nt once starts to revolve and to turn the brushes of the machine in the corresponding direction for cutting down the current: et the same time the rod I' acts upon the fichl-switch :5, which assists the brushes in reducing the current by cutting out sec tions of the field-magnet s. When the normal current has again been established the con troller armature re-establishes contact C and the regulating motor stops. A diminution of the current from the normal causes the breaking of the contact C', which sends I lie regulating cnrrent through the motor in the direction opposite to that just described. HMI with a corre sponding effect, It will be evident that at all times the resistances /0 and are in cir cuit, and as the lest two points form constant shunts to the points timid tg, no sparking whatever Lakes place when contact is broken at either of those points. The result of this is, that upon any variation in the current, not only are the brushes revolved in a corresponding direction by the regulating motor, but, as will he noted, the field-switch S is operated, to cut sections in or out, by means of the connecting arm F F: both these methods of regulation, acting in conjunction, serve to bring the machine instantly into its normal state. The switch SI is provided fcr the purpose of cutting out the regulating motor when adjusting the position of the magnets .14 while the switch is employed for short-circuiting the field-magnets when shutting down the machine. As the potential employed on the largest.sized machine approaches the neighborhood of 5,000 volts, extra precaution must be taken for insula tion of the various parts, which is made specially necessary by the static charge. which has opportunity to accumulate from the friction of the belt. The jumping of the spark, due to this accumulation, is apt to be followed by the current from the ma chine. To avoid this the armature is thor
oughly insulated with mica from the spider which holds it, and the bearings are also in sulated from the main body of the dynamo, and the latter, again. from the iron skids upon which it is mounted. Various sizes of this !tillable have been built—the largest. designed for 125 1,200-candle-power lamps, or fur 100 lamps. The diameter of the armature of this machine is 10 in. and hits 36 coils wound 1111011 it, each S in. square. One hundred anal sixty pounds of No. 17 l3. & S. wire are walla) 1111 the armahre for the 1,200-canille-pow er humps, whit.), require seven amperes, and the same weight of N. 16 wire where the 2M00 - candle- power lanq,s are employed, which take ten amperes. The speed of the machine is 700 revolutions per minute, and its total weight 5.500 lbs. The wumnnd with 1.300 lbs. of No. 8 wire. divided into two sections. One of these is wound unbroken, while the other is tapped at equal intervals by 20 wires. which are connected to the field-switches and controlled by the brush-rocker in the manner described above. The second size of this machine constructed is designed for 50 lights of 2,000 candle power each, and has 90 lbs. of wire on tho armatnre ;11111 870 on the field. The third size, designed for 30 lights, has 55 lbs. of wire on the armature and 400 lbs. on the field.
The general appearance of the machine. it will be noted, is exceedingly comp act. and the open construction adopted allows of ready access to every part for examination and repair, necessary. The machines have already been placed in several stations, where their operation has been attended with marked success. The following data refer to a machine of this type designed to operate 100 arc-lights in series: Current, 10 amperes; E. 11. E",, 5,000 volts; re sistance of field. 14 ohms : resistance of armature, 13 ohms : ampere turns in field, 42,400: ampjre turns in armature. 40.500 : number of sections in armature, 36. of 225 turns each ; size of wire on field, No. 8 B. & S.; size of wire on armature, No. 15 B. & S.; speed, 750 revolu tions per minute: weight, 6,300 lbs.
The Sperry Dynamo.-111 the rotary movement of a ring-armature between opposite ex ternal pole-pieces, the lines of force, according to one theory, enter the armature-core and traverse the coils, producing an equal magnetic effect on every portion of each coil, interior as well as exterior. According to another theory, only the exterior portion of the coils cuts the lines of force; the interior portion, as well as that on the ends, being practically idle, serving only as a conductor of the electricity generated in the exterior portion. To bring this idle portion into action, the field-magnets of the Sperry dynamo are constructed with interior as well as exterior pole-pieces, the flat ring-armature being nearly inclosed between them, by which means, it is claimed, about 92 per cent of the armature-wire is rendered effective, while, without interior pole-pieces. only 30 to 54 per cent becomes effective. Fig. 45 represents the field-magnets complete. They consist of four magnets, the four cores being attached to a heavy iron yoke. From each core two pole-pieces. like the tongs of a tuning-fork, project i horizontally, eight in all—four interior and four exterior—the two sets being arranged in two concentric circles. as shown, leaving an annular space between them. The armature, shown in Fig. 46, rotates in this space, its position being reversed, and its shaft passing through the center of the magnet-yoke. its core has the same construction as that of others already de scribed—thin, flat, sheet-iron rings, insulated with paper and bolted together, without air spaces. It is attached at the commutator end to a brass support called the spider, connected with the shaft. It is series-wound, in one closed circuit. with insulated copper wire of suitable size, the coils being connected by radial arms with the commutator in the usual manner; the ring complete being 8+ in. wide in the 35-are-light mast • s. The shaft with the armature attached can be moved horizontally by means of a screw. and the armature drawn out of the inclosing pole-pieces, and consequently out of the magnetic field, to any required extent, thereby reducing the magnet ic and electric intensities. A special feature of the new Sperry dynamo is the auto matic regulator. The brushes consist of overlapping flat copper strips attached to a movable yoke, which is con nected by means of an am to an electromagnetic regulator placed in the lamp-eircuit. Any variation in the electri cal resistance of the lamp circuit operates the keeper of the electro-magnet. By an ingenious ratchet -and - pawl device this movement adjusts the current of the clynai o in proportion to the variation in the resistance of the lamp circuit. it is claimed that 75 per cent of the total number of are-lamps may be instantly switched out without the least danger to the machine. Fig. 47 shows the machine in per spective.
Fig. 48 is ar diagram of the Waterhouse dynamo, with a closed - circuit armature A. Fig. 49 shows the Waterhouse dynamic). type No.3, on which the regulator is used, On the com nt ;war rare I h roe brushes: and the main circnit brushes. and e the auxiliary brush.
Prom the positive brush a the current passes on conductor around the field-magnets to the resistance R. The current from the mixiliary brush c passes directly to resistance R. leaving the field-magnets out of circuit. The eurrents from both circuits (ii tin and local) join at R, awl pass to the lamps, the current on the lamp-line being, the sum of the two.