595
(2)22
the following facts are established: -
1. A very large number of mains and service pipes have been already actually destroyed by the stray return currents of electric railways operating under the single trolley system: many instances of such destruction of pipes by these currents having been reported from practically every city where the single trolley system has been in use for any considerable length of time. Even where the action is too slow to be immediately discovered, the life of the mains and service pipes is inevitably greatly shortened and their value thereby necessarily proportionately decreased.
2. In the single trolley system, no matter how large the capacity of the return feeders, nor how good the bonding of the rails, and even when the continuous rail is used, some electric current will, under the law of divided circuits, flow along the water pipes; the amount of this current bearing the same proportion to the total current of the return bath, as the conductivity of the water pipes forms a part bears to the total conductivity of all the return paths offered to the current. As neither the rails nor the pipes can practically be insulated from the soil in which they are laid, the proportion of current conveyed by the pipes is considerable, even with the best track bonding known to modern science, including the welded joint.
3. The electric current, once on the pipes, must leave them to return to its source, the generator; and wherever the current leaves the pipes to pass through the soil, the pipes are damaged.
4. Electrolysis also results from differences in potential between water pipes and any other underground metal conductor, such as gas pipes; and as long as the return
595
(2)22
the following facts are established: -
1. A very large number of mains and service pipes have been already actually destroyed by the stray return currents of electric railways operating under the single trolley system: many instances of such destruction of pipes by these currents having been reported from practically every city where the single trolley system has been in use for any considerable length of time. Even where the action is too slow to be immediately discovered, the life of the mains and service pipes is enevitably greatly shortened and their value thereby necessarily proportionately decreased.
2. In the single trolley system, no matter how large the capacity of the return feeders, nor how good the bonding of the rails, and even when the continuous rail is
used, some electric current will, under the law of divided
circuits, flow along the water pipes; the amount of this
current bearing the same proportion to the total current
of the return bath, ch to ist total seducticbikkick the water pipes form a part bears used that the conductivity of all the return paths offered
to the current. As neither the rails nor the pipes can prac- ticably be insulated from the soil in which they are laid, the proportion of current conveyed by the pipes is consider- able, even with the best track bondage known to modern
science, including the welded joint.
3. The electric current, once on the pipes, must
leave them to return to its source the generator; and
wherever the current leaves the pipes to pass through the soil, the pipes are damaged.
4. Electrolysis also results from differences in
potential between water pipes and any other underground
metal conductor such as gas pipes; and as long as the
return
No comments yet.
Private notes are available after approval.