[Electric engineering.] . a position near the center, and when it isheavy they both move towards the end coils. The weight wrequired to counterbalance the repulsion effect is carried bya small auxiliary lever / that projects through the topof the case. The two secondary coils may be connectedin series to feed a single circuit, or they may be connectedto two circuits, as in the multicircuit Brush dynamo. Thewhole transformer is placed in a corrugated cast-iron casefilled with oil. This secures good insulation and makes themovements of the coils smooth, because the whole movingsystem acts like a
[Electric engineering.] . a position near the center, and when it isheavy they both move towards the end coils. The weight wrequired to counterbalance the repulsion effect is carried bya small auxiliary lever / that projects through the topof the case. The two secondary coils may be connectedin series to feed a single circuit, or they may be connectedto two circuits, as in the multicircuit Brush dynamo. Thewhole transformer is placed in a corrugated cast-iron casefilled with oil. This secures good insulation and makes themovements of the coils smooth, because the whole movingsystem acts like a dashpot. 49. Constant-current transformers may be placed eitherin the station or in a substation at a convenient point near 19 ELECTRIC LIGHTING. 41 where the lamps are to be supplied. In some instancesthey have been placed in substations and equipped withautomatic time switches that cut them out in the morningas soon as the lights are no longer needed. At light loads,a system of this kind has a poor power factor; but if. fig. 22. worked at nearly full load, the power factor is about .8, orabout as good as the power factor of a load of inductionmotors. The low power factor has been urged as an objec-tion against systems of this kind, and while it undoubtedlyis an objection, it must not be forgotten that the doingaway with arc-light dynamos and running all the lights,/. III.—32 42 ELECTRIC LIGHTING. 19 both arc and incandescent, from the same kind of alterna-tor is an advantage that goes far to outweigh the disadvan-tages of a low power factor. 50. Regulation by Means of Variable Reactance.— Fig. 23 shows another style of regulator for the operationof series alternating-current arc lamps from constant-potential circuits. It consists of a coil C mounted on theend of a lever and counterbalanced by the weight laminated core D is lu shaped and the coil slides over thecenter tongue. When all the lamps are in operation, the
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