. Electrical world. te break-down ofthe insulation at some point on the primary mains. With a primarysystem in first-class condition the weakest point would probably bebetween the coils of transformers feeding the consumers premises,the breaking down of which would subject the inside wiring to apotential to ground of anywhere between 2,620 and volts. Theresulting disturbance requires no description. That such a result is seldom known to occur is explained in two ways: First, thegeneral insulation of the primary system is seldom as high as thatof the transformers connected to it, but the
. Electrical world. te break-down ofthe insulation at some point on the primary mains. With a primarysystem in first-class condition the weakest point would probably bebetween the coils of transformers feeding the consumers premises,the breaking down of which would subject the inside wiring to apotential to ground of anywhere between 2,620 and volts. Theresulting disturbance requires no description. That such a result is seldom known to occur is explained in two ways: First, thegeneral insulation of the primary system is seldom as high as thatof the transformers connected to it, but the general improvement inoverhead construction is rapidly removing this safeguard. Second,where such a break-down has actually occurred there is rarelyenough left of the general combination, including the building where-final ground connection was made, to tell what the original troublewas. By permanently grounding wire b any crosses between the primaryand high-tension system would result in grounding the high-tension. FIGS. 2 ANU 3.—SECTIONS OF CABLES. wire upon which the cross occurred, either directly through groundconnection on b or through the transformer coils from wires a orc. It would, therefore, be impossible for any trouble, between thesetwo systems, to spread to the low-tension secondary mains or tocause serious damage to the intermediate primary system. Withboth wires b and b grounded it would be impossible for damage toresult at any point except that where cross actually occurred. Thesame arguments apply to crosses between primary and the low-tension secondary mains, so that it is unnecessary to go into detailsas to the last section of the system. The successful and safe operation of any constant-potential sys-tem requires that its voltage to ground must never exceed underany condition that normally on its circuits. From the above it shouldbe clear that the only method of insuring such results is to perma-nently ground one wire of the system, and such grounding sho
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectri, bookyear1883
