An Improved Automatic Safety Device for Electric Circuits.
Year: 1896

page_text: Date of Application, 3rd Nov., 1896-Accepted, 23rd Jan., 1897
COMPLETE SPECIFICATION.
An Improved Automatic Safety Device for Electric Circuits.
I, LEWIS G. ROWAND, of 13 North Fourth Street, in the City of Camden,
County of Camden, and State of New Jersey, United States of America,
Electrical Engineer, do hereby declare the nature of this invention, and in what
manner the same is to be performed, to be particularly described and ascertained, in
and by the following statement:-
My invention is particularly adapted for trolley lines in streets, and in its
adaptation to that purpose I will describe my invention, although it is to be under-
stood that I do not intend to limit the invention to any particular use.
In the drawings-
Figure 1 is a diagram of a single line.
Figure 2 is a diagram of a double line.
Figure 3 is a detail diagramatical view showing devices whereby the current to
the magnet may be decreased.
Speaking first of Figure 1: A is the main or trunk wire of an electric road,
B the trolley section. The return of this trolley section B before passing to
ground passes through the electro-magnet C, which has double winding, the
windings being in opposite directions. The trolley sections B pass to one of these
windings. From the magnet C, a wire c connects to ground. D is a wire connected
also with the trunk line, the trolley section B and wire D having a common
connection with the trunk line A through wire d. The wire D is connected with
the opposite winding of the magnet C to that which wire B is connected. It may
thus be seen that, speaking of the circuits formed by wire B and wire D, there are
two circuits in multiple having a connection d. with the source of current supply.
(trunk A) common to both, each circuit having a winding of the magnet C in
circuit, but the windings being opposite so that normally the currents passing
through the magnet C from the two circuits neutralize each other, and the magnet
is not energized.
Upon the connection d, common to both circuits, B and D, is placed a switch E,
which switch is normally closed the switch being controlled by the armature c of
the magnet C, the arrangement being such, as is clearly shown in the drawings,
that when the magnet is energized the armature acts to operate the switch to open
the circuits upon the portion d.
Upon both the circuits of the wires B and D) are placed resistances, F, to prevent
unnecessary current passing through the magnet.
The
The practical operation of this device may be thus described: Under ordinary
conditions the current passes from the trunk line A, both through the circuit B and
circuit D. The circuit B is the trolley circuit and feeds the trolley cars.
current from both circuits B and D passes through the magnet C, but passing in
opposite directions does not energize it. Now if, in case the trolley wire B should
break, the circuit will no longer, so far as that circuit is concerned, pass through
the magnet C. The consequence is that the current from the circuit D, passing
through the magnet C, will energize it, and the armature will open the switch and
cut off any current passing to either the circuit B or the circuit D. As a con-
sequence, if for any cause a trolley wire should break, no matter how many cars
were upon the circuit, at once the current passing to that wire would be cut off, and
there would be no danger of any live wires.

page_text: In Figure 2, the only difference existing between it and Figure 1 is that in the
former case, Figure 2, I have shown a trolley. equipment for a double track road.
In this case, instead of the section or circuit B passing directly back to the magnet,
it passes back 'over the opposite track, and then the return wire passes through the
magnet C to ground.
In order to cut off any trolley section which may be desirable in case of a fire
or for any other cause, I place upon either circuit B or D (as shown it is circuit D)
preferably at a point contiguous to the magnet C, a switch G having a ground
connection, which switch may be operated by hand, so as to short-circuit the wire B
to ground, which, of course, will have the effect of preventing it passing through
the armature C, and therefore, as in the case of the broken wire, the magnet C
will become energized and open the circuit on the common wire d. The same thing
may be accomplished by a switch which, as shown, is short circuited around the
resistance, as shown G. In many cases it is desirable that the least possible
amount of current should pass to the magnet C through circuits B and D. This
is accomplished by making the resistances F very high. In this case, when the
magnet is energized, it would be but slightly, and hence might not act upon the
magnet c. provide the following (see Fig. 3) The lever c', instead of being
acted on directly by magnet C, is acted on through the medium of pivoted lever C²,
which forms the armature of the magnet C. The lever C' has a projection in
line of movement of one end of lever C. Both levers at this point carry contact
points normally out of contact with each other. A wire from one side of
resistances F in circuit D passes to lever c', and from the other side of resistances F
a wire passes to lever C. Now suppose the circuit B to be broken: At first the
magnet C is energized by the slight amount of current in circuit D passing
resistances F, which is enough to move the lever C2 so that the contacts on it and
lever care in contact, and at once the current in circuit D passes to the magnet C
independent of the resistances, and the magnet becomes highly energized, drawing
up lever C² so that it, acting on the projection of lever c', noves said lever so as
to trip up switch E. In this connection I can, by means of the wires H and H
and switch H2 by hand, shunt the circuit B around the resistances, and thus
energize the magnet, and open circuit B, and this may be used in connection with
or in place of switch G, Figures 1 and 2.
As stated previously in the specification, while I have described my invention
in connection with the trolley wire, I do not intend to limit myself to that purpose,
as my improvement is adapted for use in any electrical circuit used for any
purpose.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1. Two circuits in multiple having a common connection with the source of
current supply, and a normally closed switch controlling said common connection,
an electro-magnet having reverse windings creating a normally ineffective field,
one winding being in one circuit and the other winding in the other circuit, said
magnet controlling the operation of the switch, and adapted when its field becomes
effective to open said switch.
2. Two circuits in multiple having a common connection with the source of
current supply, and a normally closed switch controlling said common connection,
an electro-magnet having reverse windings creating a normally ineffective field,
one winding being in one circuit and the other winding in the other circuit, said
magnet controlling the operation of the switch and adapted when its field becomes
effective to open said switch, and a switch adapted when operated to cut off the
current from one of the magnet windings.
3. The combination with a main electric circuit, a secondary circuit, an electro-
magnet included in both circuits, said magnet having reverse windings creating a
normally ineffective field, one winding being included in the main circuit and the

page_text: other in the other circuit, and a normally closed switch controlling the current in
the main circuit controlled by said magnet, said magnet being adapted when its
field becomes effective to open said switch.
4. Two circuits in multiple having a common connection with the source of
current supply, and a switch controlling said common connection, an electro-magnet
having reverse windings, creating a normally ineffective field, one winding being in
one circuit, and the other winding in the other circuit, said magnet controlling the
operation of the switch and adapted, when its field becomes effective, to open said
switch, resistances in both circuits, and means when said magnet field becomes
effective to shunt the current about one of said resistances.
5. The combination with a main electric circuit, a secondary circuit, an electro-
magnet included in both circuits, said magnet having reverse windings creating a
normally ineffective field, one winding being included in the main circuit, and the
other in the other circuit, and a switch controlling the current in the main circuit
controlled by said magnet, said magnet being adapted, when its field becomes
effective, to open said switch, resistances in both circuits, and means, when the
magnet becomes effective, to shunt the current about one of said resistances.
6. Two circuits in multiple having a common connection with the source of
current supply, and a switch controlling said common connection, an electro-magnet
having reverse windings, creating a normally ineffective field, one winding being
in one circuit, and the other winding in the other circuit, said magnet controlling
the operation of the switch and adapted, when its field becomes effective, to open
said switch, resistances in both circuits, and means independent of the magnet to
shunt the current about one of said resistances.
7. The combination with a main electric circuit, a secondary circuit, an electro-
magnet included in both circuits, said magnet having reverse windings, creating a
normally ineffective field, one winding being included in the main circuit, and the
other in the other circuit, and a switch controlling the current in the main circuit
controlled by said magnet, said magnet being adapted, when its field becomes
effective, to open said switch, resistances in both circuits, and means independent
of the magnet to shunt the current about one of said resistances.
8. Two circuits in multiple having a common connection with the source of
current supply, and a normally closed switch controlling said common connection,
an electric device having double windings, making said device normally ineffective,
one winding being in one circuit, and the other winding in the other circuit, said
electric device controlling the operation of the switch and adapted when rendered
effective to open said switch.
9. Two circuits in multiple having a common connection with the source of
current supply, and a normally closed switch controlling said common connection,
an electric device having double windings, making said device normally ineffective,
one winding being in one circuit, and the other winding in the other circuit, said
electric device controlling the operation of the switch, and adapted when rendered
effective to open said switch and a switch adapted to cut the current from one of
said windings.
10. The combination with a main electric circuit, a secondary circuit, an electric
device included in both circuits, said device having double windings making said
device normally ineffective, one winding being included in the main circuit, and
the other in the other circuit, and a normally closed switch controlling the current
in the main circuit controlled by said electric device, said device, when rendered.
effective, being adapted to open said switch.
11. Two circuits in multiple having a commen connection with the source of
current supply, and a switch controlling said common connection, an electric device
having double windings, making said device normally ineffective, one winding
being in one circuit, and the other winding in the other circuit, said electric device
controlling the operation of the switch, and adapted, when rendered effective, to
open said switch, resistances in both circuits, and means controlled by said electric
device to shunt the current about one of said resistances.

page_text: 12. The combination with a main electric circuit, a secondary circuit, an electric
device included in both circuits, said electric device having double windings,
making said device normally ineffective, one winding being included in the main
circuit, and the other in the other circuit, and a switch controlling the current in
the main circuit, controlled by said electric device, said electric device being
adapted, when rendered effective, to open said switch, resistances in both circuits,
and means controlled by the electric device to shunt the current about one of said
resistances.
13. Two circuits in multiple having a common connection with the source of
current supply, and a switch controlling said common connection, an electric device
having double windings, making said device normally ineffective, one winding
being in one circuit, and the other winding in the other circuit, said electric device
controlling the operation of the switch, and adapted when rendered effective, to
open said switch, resistances in both circuits, and means independent of the electric
device to shunt the current about one of said resistances.
14. The combination with a main electric circuit, a secondary circuit, an electro-
magnet included in both circuits, said magnet having reverse windings, creating a
normally ineffective field, one winding being included in the main circuit, and the
other in the other circuit, and a normally closed switch controlling the current in
the main circuit controlled by said magnet, and adapted when its field becomes
effective to open said switch, and means to open one of said circuits independent
of the magnet switch.
15. The combination with a main electric circuit, a secondary circuit, an electric
device included in both circuits, said device having double windings, making said
device normally ineffective, one winding being included in the main circuit, and
the other in the other circuit, and a normally closed switch controlling the current
in the main circuit controlled by said electric device, said device when rendered
effective being adapted to open said switch, and means to open one of said circuits
independent of the electric device switch.
16. Two circuits having a common source of current supply, a switch controlling
the admission of current from the source of current supply to said circuits, an
electric device having double windings, making said device normally ineffective,
one winding being in one circuit, the other winding in the other circuit, said electric
device controlling said switch and adapted when rendered effective, to open said
switch.
17. In an electric railroad, the combination of a source of current supply, a
main feeder wire, trolley section wires each having connection with the main
feeder wire, a normally closed switch controlling the admission of current from the
feeder wire to each trolley section, an electric device having double windings, one
winding in the trolley section wire circuit, the other in a circuit independent of the
trolley section said electric device controlling the operation of the switch, and
adapted when the trolley wire breaks to operate to open said switch.
18. In an electric railroad, the combination of a source of current supply, a
main feeder wire, a trolley section wire having connection with the said main
feeder wire, a normally closed switch controlling the admission of current from the
feeder wire to said trolley section, an electric device having double windings, one
winding in the trolley section wire circuit, the other in a circuit independent of the
trolley section wire, said electric device controlling the operation of the switch and
adapted when the trolley section wire breaks to open said switch.
19. In an electric railroad, the combination of a source of current supply, a
trolley section having connection with the source of current supply, a normally
closed switch controlling said connection, an electric device having double windings,
one winding in the circuit including the trolley section, the other in the circuit
independent of the trolley section, said electric device controlling the operation of
the switch and adapted when the trolley section is broken to operate to open said
switch.
20. In combination, an electric circuit, a source of current supply, a normally

page_text: closed switch controlling the admission of current from the source of supply to said
circuit, an electric device on a circuit independent of the first mentioned circuit,
adapted when its field is effective to open said switch, and an electric device on the
first mentioned circuit acting against said first mentioned electric device and
adapted with the normal resistance of the main circuit to neutralize the action of
the first mentioned electric device.
21. In combination, an electric circuit, a source of current supply, a normally
closed switch controlling the admission of current from the source of supply to said
circuit, an electric device on a circuit independent of the first mentioned circuit.
but having the same source of current supply adapted when its field is effective to
open said switch, and an electric device on the first mentioned circuit acting against
said first mentioned electric device and adapted with the normal resistance of the-
main circuit to neutralize the action of the first mentioned electric device.
Dated this 22nd day of September 1896.
LEWIS G. ROWAND.
Haseltine, Lake & Co.,
45 Southampton Buildings, W.C., Agents for the Applicant.