Methods of and Apparatus for Preventing the Sticking, through Leakage Currents or the like, of Electric Railway Section Switches.
Year: 1897

page_text: Date of Application, 10th Sept., 1097
Complete Specification Left, 18th July, 1898- Accepted, 16th Sept., 1898
Date of Application, roth Dept., 1091
Complete Specification Left, 18th July, 1898- Accepted, 16th Sept., 1898
PROVISIONAL SPECIFICATION.
Methods of and Apparatus for Preventing the Sticking, through
Leakage Currents or the like, of Electric Railway Section
Switches.
A communication from abroad by THE ESMOND INTERNATIONAL ELECTRIC
TRACTION COMPANY, of New York, United States of America.
I, JAMES GRIEVE LORRAIN, M. Inst. E.E., M.I. Mech. E., of Norfolk House,
Victoria Embankment, London, W.C., in the County of Middlesex, Chartered
Patent Agent, do hereby declare the nature of this invention (as communicated
to me from abroad) to be as follows:-
In certain systems of electric railways it is usual to employ switches for the
purpose of temporarily connecting the working sections or contact points, over
which the car or train is passing, with the main supply conductor, so that current
may be taken from the said conductor to the motor or motors, and so on to the
return rails on which the car or train travels.
Now in systems of this kind there is a danger, when surface leak-
age is considerable, of the switch remaining closed through current
leakage from the working section or contact point to the return rails after the
motor has passed beyond the position at which it takes current from the said
working section or contact point.
This invention is designed to obviate the sticking of the switches and the
desired result may be effected as follows:-
In one way of carrying this invention into effect the track is provided with
what for the purposes of this specification may be termed leakage plates. These
leakage plates may consist of rods, sheets, blocks, or other shaped masses of con-
ducting material of any desired dimensions and they may either lie on the surface
of the road or be embedded therein. They may be placed at any convenient
part of the track but it is essential that they be placed electrically nearer to a
rail than are the working sections or points. The said leakage plates are
electrically connected to the said switches at a part thereof which electri-
cally speaking is situated between the switch coil and the part at which
contact with the supply conductor is made and broken.
Let us assume that by reason of rain or otherwise the current leakage from the
working section is such, that, in the absence of this invention, sufficient current
would flow through the switch coil after the car or train had passed to maintain
the switch closed. Under such circumstances the interposition of leakage plates
will present an easier path for the current which would now leave the switch
instead of passing through the coil and would flow to the leakage plate and thence
leak to the return.
The connection between the switch and the leakage plate may either be a
permanent one or it may be one effected by a movable contact.

page_text: When desired a fuse may be placed in the circuit between the switch and the
leakage plate. Likewise one plate may be made to act for several of the
switches.
Another (or second) way of obviating such sticking of the switches is based
upon the employment of what for the purposes of this specification may be termed
auxiliary contact sections and of electromagnetic switches (hereinafter termed
anti-leakage switches) whose function it is to open the circuit between the main
supply conductor and supply switch, or between the main conductor and the
motor when the car has passed. With the device just mentioned, what may be
termed an auxiliary collector, or contact brush, carried by the car, and used to
make contact with the said auxiliary contact sections, may be employed.
In order that this second way of carrying the invention into effect may be
more readily understood, two arrangements according to which it may be employed,
may be cited by way of types or examples.
In the first of the said two arrangements typical of the said second way of
carrying this invention into effect. working conductor sections, in this case
arranged in sets of three, supply switches, working or supply collectors, a main
supply conductor, and rails (or other return circuit) are employed. A motor, a
storage battery, used for picking up purposes, and a hand or controller switch
are also employed. The devices hereinbefore mentioned do not per se form parts
of my present invention, but with them are also employed auxiliary contact
sections, (in the present case one auxiliary contact section being employed with
each supply switch), and auxiliary collectors designed to make contact with the
said auxiliary working sections and convey current therefrom, as will be herein-
after described, together with anti-leakage switches.
Now let us assume that on account of leakage the switch lever of a supply
switch is sticking, or in other words remaining in its closed position although
contact has ceased, between the working or supply collectors and the working
conductor section connected with the said supply switch. An auxiliary
collector is now in contact with an auxiliary contact. The current
will now pass from the main supply conductor through the switch
lever of the anti-leakage switch, contact points, supply switch lever,
electromagnet, auxiliary contact section, auxiliary collector, contact stud, switch
arm, motor and so by a wheel of the car and rails back to the generating station.
In so passing the electromagnet will be energized, the anti-leakage switch lever
will be attracted and contact between said lever and its contact point will be
. broken. No current can now pass through the electromagnet of the supply
switch and no leakage from the working conductor sections can take place...
In a second arrangement of this second way of carrying this invention into
effect, it is contemplated to arrange the auxiliary contact sections in line with the
working conductor sections, and the auxiliary collectors in line with the working
or supply conductors.
a
.
In this case when the auxiliary circuit touches an auxiliary contact section it
completes the circuit through the immediately preceding anti-leakage switch.
Thus let us assume that the car after leaving a given position passes on so, that
supply switch is closed and the auxiliary collector makes contact with an
auxiliary contact section, but leaving the supply switch sticking. Current will
now pass from the supply conductor by the lever of the anti-leakage, switch,
contact points, connecting piece, electromagnet, contact point, ¡connecting piece
of supply switch, lever, contact point, auxiliary contact section, auxiliary collector
and so on as described in the former arrangement. The lever of the supply
switch will thus be dropped.
In a third way of carrying this invention into effect the desired result may be
obtained by establishing what for the purposes of this specification may be termed
a leakage balance.
This part of the invention; in so far as the method is concerned, consists in
establishing a leakage balance or balance of forces exerted by currents passing

page_text: through two circuits or parts of a circuit in such manner that they will counteract
one another and exert no resultant force which would cause the switch to stick.
This part of the invention, in so far as the apparatus is concerned, consiste
mainly in a switch magnet differentially wound or having upon it two circuits
or two branches of one circuit in such manner that the forces set up by currents
flowing through the said circuits or branches of the said circuit shall neutralize
one another so that the said magnet will no longer attract its armature.
Let us assume that on an electric railway of the well-known surface contact
type, we place between the rails on which the cars travel, two working contact
sections through which current is supplied to the cars when the said sections are
in contact with the collectors carried by the said cars, and that the automatic
supply switch connected with the supply conductor is closed. When now a car
has come over the working contact sections the switch will be picked up in any of
the well-known ways. When however, the car has moved on and its collectors no
longer; make contact with the working contact sections it is necessary that the
switch lever should be dropped back to its open position for the purpose of opening
the circuit. There is a danger however, especially in wet weather, of leakage
between the working sections and the rails; which leakage would tend to maintain
the switch lever in its closed position, and therefore leave the working sections
in a live condition and this would take place if, instead of adopting this invention,
an ordinary pick up magnet were used in the ordinary way. The method and
apparatus constituting the present invention is therefore employed.
The action is as follows, and we may assume that the resistances of the two
branches of the circuit are made equal or approximately equal, and that there is
leakage between the working sections and the rails. Such leakage will not now
however cause the switch to stick, because it will be obvious that the resultant
magnetic effect of the current passing through the two branch windings of the
core will be nil, the magnetic effect produced by the one branch on its half of
the core neutralizing the magnetic effect produced by the other branch upon its
half of the core. The result of such neutralization will be that the switch
lever will at once be freed, and allowed to drop.
A difficulty which might arise and prevent the satisfactory working of this
part of the invention as just described consists in the chance of there being a
greater leakage at one side of the track than at the other. Thus let us assume that
owing for example to the existence of a pool of water between say the left-hand
contact section and the left-hand rail there is greater leakage between the said
section and rail than-between the right-hand section and the right-hand rail.
This would prevent the balance being established and more current would flow
through the one winding of the switch magnet than through the other, and as a
result the switch lever might be held up. This difficulty may be overcome by
short circuiting the switch magnet or the contact sections by electrically connect-
ing the said sections or the two branches of the circuit or the two separate
circuits when such are employed.
One convenient way of doing this is by means of a conductor trailed or carried
behind the car and which, when it comes in contact with the working sections,
bridges them across. The two working sections now become for practical purposes,
one; and the two windings or paths for the current offer a practically equal
resistance so that the balance is established and the switch lever dropped.
Or, portions of the circuit may be bridged or otherwise connected by a resistance,
which latter may when desired be brought into circuit by the switch lever, and
so bring about the same practical result.
It is not necessary that the bridging be effected by a bridging device carried
or drawn by the car or train. The track may be so constructed that such bridging
is brought about naturally. Thus instead of having the contact sections of the
usual form they may be constructed with their upper surfaces sloping downwards
and inwards towards one another so as to leave à trough-shaped space between
them. The effect of this is that in wet weather a pool of water will collect in the

page_text: said space so as to establish a leakage current between the working sections and
these latter will be practically united by a liquid bridge so that the two circuits
or windings on the switch magnet core now offer practically equal resistance so
that the balance is established and the switch lever dropped.
Instead of having the contact sections constructed with sloping upper surfaces
so as to obtain a single trough-like space between them, the upper surfaces of the
contact sections may be provided with grooves, channels or recesses adapted to
collect water and thus form a liquid bridge.
In a modification, instead of causing the pool of water to collect between the
contact sections the said contact sections (suitably constructed as aforesaid) may
be placed one in close proximity to each rail so that the water may collect and
liquid bridges be formed between the section's and the rails.
Dated this 15th day of September 1897.
J. G. LORRAIN,
Communicatee.
Methods of and Apparatus for Preventing the Sticking, through
Leakage Currents or the like, of Electric Railway Section
Switches.
A communication from abroad by THE ESMOND INTERNATIONAL ELECTRIC
TRACTION COMPANY, of New York, United States of America.
I, JAMES GRIEVE LORRAIN, M. Inst. E.E., M.I. Mech. E., of Norfolk House,
Victoria Embankment, London, W.C., in the County of Middlesex, Chartered
Patent Agent, do hereby declare the nature of this invention (as communicated
to me from abroad) and in what manner the same is to be performed to be particu-
larly described and ascertained in and by the following statement:-
-
In certain systems of electric railways it is usual to employ switches for the
purpose of temporarily connecting the working sections or contact points, over
which the car or train is passing, with the main supply conductor, so that current
may be taken from the said conductor to the motor or motors, and so on to the
return rails on which the car or train travels.
Now in systems of this kind there is a danger, when surface leakage is con-
siderable, of the switch sticking, that is to say remaining closed through current
leakage from the working section or contact point to the return rail after the
motor has passed beyond the position at which it takes current from the said
working section or contact point.
This invention is designed to obviate the sticking of the switches and the
desired result may be effected as follows:-
In one way of carrying this invention into effect the track is provided with
what for the purposes of this specification may be termed leakage plates. These
leakage plates may consist of rods, sheets, blocks or other shaped masses of con-
ducting material of any desired dimensions and they may either lie on the surface
of the road or be embedded therein. They may be placed at any convenient
part of the track but it is essential that they be placed electrically nearer to a
rail than are the working sections or points. The said leakage plates are
electrically connected to the supply or section switches at a part thereof which
electrically speaking is situated between the switch coil and the part at which
contact with the supply conductor is made and broken.

page_text: This is diagrammatically illustrated in Figure I in which 1, 2 are the rails
or other return circuit, 3, the main supply conductor, 4, 5, working contact
sections and 6, 7, the section or supply switches, 8, 9, are the leakage plates
which as is shown are placed nearer to the rails than are the working sections
or points. The arrangement of supply switches and working contact sections
shown in this figure forms no part of the present invention, such arrangement
being already well known in the art.
Let us assume that by reason of rain or otherwise the current leakage from
the working section 4 is such, that, in the absence of the leakage plate 8, sufficient
current could flow through the switch coil 6 after the car or train had passed to
maintain the switch closed. Under such circumstances the employment of the
leakage plate 8, will present an easier path for the current which instead of
traversing said switch coil, will flow by lead 10, contact point 11, switch lever 12,
lead 13, to leakage plate 8 and thence leak to the return rail 1. The instant
such leakage takes place current will no longer flow through switch coil 6
and lever 12 will of course drop and the current cease to flow.
When desired a fuse may be placed in the circuit between the switch and the
leakage plate. Likewise one plate may be made to act for several switches by
connecting it to said switches in manner shown.
Another (or second) way of obviating such sticking of the switches is based
upon the employment of what for the purposes of this specification may be termed
auxiliary contact sections and of electromagnetic switches (hereinafter termed
anti-leakage switches) whose function it is to open the circuit between the main
supply conductor and the supply switch when the car has passed. With the
device just mentioned, what may be termed an auxiliary collector or contact
brush, carried by the car, and used to make contact with the said auxiliary contact
sections, may be employed.
This second way of carrying the invention into effect may be more readily
understood by reference to the diagram Figure II in which A, A1, A2, A3, A
and A5 are the working conductor sections, in this case arranged in sets of three,
and B, B1, B3, 133 are the working or supply collectors. 3 is the main supply
conductor as before, and 1 the rails or other return circuit. E is the motor, Fa
storage battery, used for picking-up purposes, G a hand or controller switch,
and 6, 7, supply switches. The devices herein before mentioned do not per se
form parts of my present invention.
14, 14 are.
the auxiliary contact sections, in the case shown one auxiliary
contact section being employed with each supply switch. 15, 15% are the auxiliary
collectors designed to make contact with the said auxiliary working sections and
convey current therefrom, as will be hereinafter described. 16, 17 are the anti-
leakage switches.
The
Let us assume that the parts are in the position shown in Figure II, and that
the switch lever 12 of supply switch 6 is sticking, or in other words remaining in
its closed position although contact has ceased between the working or supply
collectors and the working conductor sections connected with supply switch 6.
The auxiliary collector 15 is now in contact with auxiliary contact 14.
current will now pass from the main supply conductor 3 through lead 18, the
switch lever 19, of the anti-leakage switch, contact point 20, lead 21, contact
point 11, supply switch lever 12, lead 22, electromagnet 23, lead 24, auxiliary
contact section 14, auxiliary collector 15, lead 25, contact stud 26, switch arm 27,
lead 28, lead 29, motor E, lead 30, and so by wheel 31 and rail 1 back to the
generating station. In so passing electromagnet 23 will be energized, anti-leakage
switch lever 19 will be attracted and contact between said lever 19 and contact
point 20 will be broken. No current can now pass through the electromagnet of
supply switch 6 and no leakage from the working conductor sections can take
place.
In a third way of carrying this invention into effect the desired result may be
;

page_text: obtained by establishing what for the purposes of this specification may be termed
a leakage balance.
.
This part of the invention, in so far as the method is concerned, consists in
establishing a leakage balance or balance of forces exerted by currents passing
through two circuits or parts of a circuit in such manner that they will counteract
one another and exert no resultant force which would cause the switch to stick.
This part of the invention, in so far as the apparatus is concerned, consists
mainly in a switch magnet differentially wound or having upon it two circuits
or two branches of one circuit in such manner that the forces set up by currents
flowing through the said circuits or branches of the said circuit shall neutralize
one another so that the said magnet will no longer attract its armature.
This part of the invention is illustrated diagrammatically in Figure III.
In the diagram Figure III, 1 and 2 are the rails on which the cars travel, 3 is
the supply conductor by which electrical energy is transmitted from the supply
station, 4 and 5 are the working contact sections through which current is supplied
to the cars when the said sections are in contact with the collectors carried by the
said cars, and 6 is the automatic supply switch, all as before.
Let us assume that a car has come over the working contact sections 4, 5 and
that the switch has been picked up in any of the well known ways so as to bring
the armature lever 12 from the position shown in dotted lines to that shown in
full lines. Contact is now made at the point 11 and current is supplied from the
main supply conductor 3 to the motor on the car in the well known way the
current returning by the rails.
When the car has moved on and its collectors no longer make contact with
sections 4 and 5 it is necessary that the switch lever 12 should be dropped back
to the position shown in dotted lines for the purpose of opening the circuit at the
point 11. There is a danger, however, especially in wet weather, of leakage between
the working sections 4 and 5 and the rails 1 and 2; which leakage would tend
to maintain the switch lever in its closed position, and therefore leave the working
sections 4 and 5 in a live condition and this would take place if, instead of
adopting the method of employing the magnet 32, an ordinary pick up magnet
were used. I therefore adopt the method and apparatus constituting this part
of the present invention.
A reference to the drawings will show that instead of using a pick up magnet
consisting of a core wound in the usual manner I employ a core wound differen-
tially with two circuits or a circuit divided into two branches the latter form being
that illustrated in the figure, where it will be seen that the lead 33 is divided into
two branches 34 and 35 the former passing round the lower half of the magnet
core and onwards to one of the working sections, for example 5, whilst the other
branch passes round the upper half of the core and on to the other working
section 4.
The action is as follows, and we may assume that the resistances of the two
branches of the circuit are made equal or approximately equal. Assume now
that there is leakage between the working sections and the rails. Such leakage
will not cause the switch to stick, or in other words hold up the armature, because
it will be obvious that the resultant magnetic effect of the current passing through
the two branch windings of the core will be nil, the magnetic effect produced by
the one branch on its half of the core neutralizing the magnetic effect produced
The result of such neutralization
by the other branch upon its half of the core.
will be that the switch lever 12 will at once be freed, and allowed to drop.
A difficulty which may arise and prevent the satisfactory working of my inven-
tion as hereinbefore described, consists in the chance of there being a greater
leakage at one side of the track than at the other. Thus let us assume that owing
for example to the existence of a pool of water between contact section 4 and
rail 1 there is greater leakage between rail 1 and section 4 than between rail 2
and section 5. This would prevent the balance being established and more

page_text: current would flow through winding 35 than through winding 34; and the switch
lever might be held up. I may overcome this difficulty by short-circuiting the
switch magnet or the sections' by electrically connecting the said sections, or the
two branches of the circuit or the two separate circuits, when such are employed.
One convenient way of doing this is shown in Figure IV in which 36 is a con-
ductor (hereinafter termed a "trailing bridge") trailed or carried behind the car
and which when it comes in contact with the sections 4 and 5 bridges them across.
Sections 4 and 5 now become one for practical purposes and the two paths offer
a practically equal resistance so that the balance is established and the switch
lever dropped.
The desired result may be brought about otherwise than by a trailing bridge
as shown in Figure IV. The track may be so constructed that such bridging is
brought about naturally. Thus instead of having the contact sections of the
usual form they may be constructed with their upper surfaces sloping downwards
and inwards towards one another so as to leave a trough-shaped space between
them. The effect of this is that in wet weather a pool of water will collect in the
said space so as to electrically connect these working sections by a liquid bridge
so that the two circuits or windings on the switch magnet core now offer practically
equal resistance, so that the balance is established and the switch lever dropped.
This is diagrammatically illustrated in Figure V, in which instead of having the
contact sections of the usual form I construct them with sloping upper surfaces 37,
38 as shown. Here it will be seen that the said surfaces slope downwards and
inwards towards one another so as to leave a trough shaped space 39 between
them. The effect of this is that in wet weather a pool of water will collect in the
said space 39 and an electrical connection will be established between the
sections 37 and 38.
Thus united by a liquid bridge the sections become practically one after the car
has passed when the circuit is no longer through the motor, so that the two
branch circuits now offer practically equal resistance so that the balance is
established and the switch lever dropped.
In Figures VI and VII I show in vertical section and in plan respectively,
another form of working contact section by means of which a liquid bridge can be
constituted. In this case instead of sloping the upper surfaces 37 and 38 towards
one another so as to obtain a single trough-like, space between them I provide
the upper surfaces of the section with grooves, channels or recesses 40 adapted to
collect water and then form a liquid bridge.
In Figure VIII I show a modification of this part of my invention. In this
case I place the working sections close to the rails so that water may collect and
establish a liquid bridge between the working sections and the rails, instead of
between the working sections themselves. The effect is the same.
Having now particularly described and ascertained the nature of this inven-
tion (as communicated to me from abroad) and in what manner the same is to be
performed I declare that what I claim is:
1. The method of preventing the sticking, through leakage currents or the like,
of electric railway section switches by employing leakage plates substantially as
set forth.
2. The method of preventing the sticking, through leakage currents or the like,
of electric railway section switches by employing anti-leakage switches substan-
tially as set forth.
3. The method of preventing the sticking, through leakage currents or the like,
of electric railway section switches by employing a leakage balance substantially
as set forth.
4. The method of preventing the sticking, through leakage currents or the like,
of electric railway section switches by employing a leakage balance and a trailing
bridge substantially as set forth.

page_text: 5 The method of preventing the sticking, through leakage currents or the like,
of electric railway section switches by employing a leakage balance and a liquid
bridge substantially as set forth.
6. A leakage plate used substantially as and for the purpose set forth.
7. An anti-leakage switch used substantially as and for the purpose set forth.
8: In apparatus for preventing the sticking, through leakage currents and the
like, of electric railway section switches, the combination of anti-leakage switch
and auxiliary contact section substantially as set forth.
9. In apparatus for preventing the sticking, through leakage currents or the
like, of electric railway section switches, a switch-magnet with opposed windings,
substantially as set forth.
10. In apparatus for preventing the sticking, through leakage currents or the
like, of electric railway section switches, the combination of switch-magnet with
opposed windings, contact sections and trailing bridge substantially as set forth.
11. In apparatus for preventing the sticking, through leakage currents or the
like, of electric railway section switches, working. contact sections so shaped and
arranged as to collect a liquid bridge substantially as set forth.
12. In apparatus for preventing the sticking, through leakage currents or the
like, of electric railway section switches, the combination of switch-magnet with
opposed windings and working contact sections so shaped and arranged as to
collect a liquid bridge substantially as set forth.
1000