Improved Arrangement of Conductors for Electric Series Traction.
Year: 1889

page_text: Date of Application, 28th Oct., 1889
Complete Specification Left, 25th July, 1890 Accepted, 30th Aug., 1900
Complete specification Lent util vuly,
PROVISIONAL SPECIFICATION.
Improved Arrangement of Conductors for Electric Series Traction.
I, JOHN MACINTOSH MACKAY MUNRO, of 136 Bothwell Street, Glasgow, in the County
of Lanark, North Britain, Electrical Engineer do hereby declare the nature of this
invention to be as follows:-
This invention relates to the arrangement of conductors for carrying the electricity
to the motors of vehicles driven by electricity, the object of which is to provide a
system of conductors for series traction which will allow of having greater length of
continuous conductors than has hitherto been in practical use.
In my system the whole circuit is laid off in a number of sections which may be
equal to the greatest number of cars or trains intended to be run upon it at one
tiine. It is especially suitable for an overhead or underground city circular railway, but
may also be used for tramways laid along the streets. In such cases the stations would
be fixed as nearly as possible at equal distances apart (say 1 mile).
I employ two conductors, one or other of which is broken at each station.
In order to facilitate the description I will call the conductors A, and B.
The conductor A, will be broken at the 1st, 3rd etc. stations, and the conductor B,
will be broken at the 2nd, 4th, etc. stations.
Suppose there is a train or car at each station preparing for the journey, the circuit
will be broken at all the stations. As each train is ready to start, the driver turns bis
switch so as to connect the conductors A, and B, through the motor of his train, but
no current will pass until the last train is ready and its switch turned to "make" the
last break in the circuit.
When the last motor is switched on the current will enter the circuit by conductor A,
pass through the motor of the first train to conductor B, along this conductor to the
second train, through its motor to conductor A, along it and through the motor of
third train to conductor B, and so on till it returns to the other pole of the dynamo.
Thus all the trains will start together and travel along from one station to the next.
The current will be cut off all the motors together by one of the drivers breaking the
circuit. It may be found of advantage to automatically reduce the amount of current
supplied to the motor as the train approaches the station. This can be accomplished
in several ways. For instance, I may arrange that as the train approaches the station,
an extra resistance is thrown into the circuit between the train and the dynamo.
Instead of breaking the circuit for stopping, I may arrange to short circuit between
the conductors A, and B. With this arrangement, each train can be stopped or started
independently of the others in the circuit. In this case the dynamo might be arranged
to give constant current, or preferably a current varying to suit the special demands
of the line, for example on receipt of the signal that all trains were ready, current
might be by hand, or automatically by the signal raised from nearly zero rapidly to
maximum, then gradually decrease till the signal again indicated that all the trains
had arrived at their stations. The final current would serve to enable any driver to
reverse or go forward slowly, if not quite at position desired.
In some lines, particularly in street tramways, it would be almost impossible to keep
the cars in the circuit at equal distances from one another. To provide for this I
arrange that each car as it passes along reverses a lever which makes a connection in
one of the conductors, and makes a break in the continuity of the other conductor.
Thus if a car is going along, all the levers ahead are lying, say to the right, having
been put so by the preceding car, and all the levers behind are to the left, having been
put so by itself.
The current will thus run along the left-hand conductor through the motor of the
and along the right-hand conductor to the motor of the preceding car, and
car,

page_text: Any of these levers or connections may, where more convenient, be reversed by
pointsmen who can thus control the traffic; or the changes of electrical resistance
caused by the car contacts as they pass over the sections, may be utilized to actuate
automatic appliances for reversing the said levers or connections.
Dated this 26th day of October 1889.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.
COMPLETE SPECIFICATION.
Improved Arrangement of Conductors for Electric Series Traction.
I, JOHN MACINTOSH MACKAY MUNRO, of 136 Bothwell Street, Glasgow, in the
County of Lanark, North Britain, 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 :-
This invention relates to the arrangement of conductors for carrying the electricity
to the motors of vehicles driven by electricity, the object of which is to provide a
system of conductors for series traction which will allow of having greater length of
continuous conductors than has hitherto been in practical use.
In my system the whole circuit is laid off in a number of sections which may be
equal to the greatest number of cars or trains intended to be run upon it at one time.
It is especially suited for an overhead or underground city circular railway. In such
cases the stations would be fixed as nearly as possible at equal distances apart (say for
example one mile). It may also be used for tramways laid along streets.
I employ two conductors, one or other of which is broken at each station. Where
the railway is not of the circular type the electric circuit is still made "circular" by
putting in series the twin conductors of the down and the up line, the generating
dynamo or dynamos being inserted at a convenient point or points in the line. When
the railway is a single line of rails, not having its two ends contiguous, a return wire
or earth will be required besides the twin conductors described. Connection between
the car motors and the conductors may be made by sliding or rolling contacts, or any
of the well-known methods.
In order to facilitate the description, I will call the twin conductors A and B.
The conductor A will be broken at the 1st, 3rd etc. stations, and the conductor B
will be broken at the 2nd, 4th etc. stations.
Suppose there is a train or car at each station preparing for the journey, the circuit
will be broken at all the stations. As each train is ready to start, the driver turns his
switch so as to connect the conductors A and B through the motor of his train, but no
current will pass until the last train is ready and its switch turned to "make" the last
break of the circuit.
When the last motor is switched on, the current will enter the circuit by conductor A,
pass through the motor of the first train to conductor B, along this conductor to the
second train, through its motor conductor A, along it and through the motor of third train
to conductor B, and so on till it returns to the other pole of the dynamo, all as shown in
Figure 1. Thus all the trains will start together and travel along from one station to
the next. The current will be cut off all the motors together by one of the drivers
breaking the circuit so that each driver has the power in the case of accident of
suspending the whole traffic. It may be found of advantage to automatically reduce
the amount of current supplied to the motor as the train approaches the station. This
can be accomplished in several ways. For instance, I may arrange that as the train
approaches the station, an extra resistance is thrown into the circuit between the train
and the dynamo, or a similar object can be attained by forming the line so that the
train rises on an incline as it approaches the station, and when at the station is just
beyond the crest and on the downward slope, or the electromotive force of the dynamos
may be reduced by cutting off steam from engine or otherwise.

page_text: Instead of breaking the circuit for stopping, I may arrange to short-circuit between
the conductors A and B. With this arrangement each train can be stopped or started
independently of the others in the circuit. In this case the dynamo might be arranged
to give constant current, or preferably a current varying to suit the special demands of
the line, for example on receipt of the signal that all trains were ready, current might
be by ban or antomatically by the signal raised from nearly zero rapidly to maximum,
then gradually decrease till the signal again indicated that all the trains had arrived
at their stations. The final current would serve to enable any driver to reverse or go
forward slowly if not quite at position desired.
So far the point of novelty consists in having sectional twin conductors running side
by side, the sections being of such length that the cars can run over them in approxi-
mately equal time, and in thus working and controlling a set of cars numerically equal
to the number of gaps in the twin conductors. These sections as shown in Figures 1
and 2 have no switches or contact pieces of any kind save those on the
motor cars.
-
In Figures 1 and 2, the marks + and indicate a possible position of the source
of current. The double-headed arrows show the direction in which the cars (), (1, 0², C³
are at the moment supposed to be moving. Although in circular city railways and
similarly arranged lines the above is perhaps the most simple and uncomplicated
method of series working yet devised, yet in some situations it would be desirable to
be able to reduce the number of locomotive cars at any time without making a special
re-arrangement of the line. I now describe several methods of effecting this:-
Figure 4 shows same arrangement of twin conductors as Figure 2, but has at each
gap a switch as S which can connect together the consecutive sections of B. When
any motor begins to draw current from, or alternatively when any motor car comes
upon. any section, the switch as at S, S2, S3, Figure 4 is opened, and so the current
can only pass from that section of B to the next section of B by passing through
the car to A, and thence to the succeeding section at the next gap crossing G. When
no car is upon, or at least drawing current from, a section, the switch thereon closes
as at S¹ S4, and so the current can proceed straight along B from the one section te
the next. At the gap where the dynamo is inserted, the switch as at S³ joins B to A
when no car is on its section. When one of the cars on Figures 1 or 2 is to be stopped,
then as already explained, instead of breaking the circuit and so stopping all the cars,
the section on which it is may he short-circuited. This may not only be done by
switches on the cars, but may be done by switches on or near the line, and in this
way provision is made for the continuity of the circuit as a whole when a section, (or
for that matter all the sections) is without a motor car taking current from it. Such
an arrangement is shown at Figure 3. Wherever there is a section with a car, the
switches S S, of which there may be one or more to each section, are open. When
there is no car the switches close and connect A to B as at S° So. Both conductors
of such a section help to carry current on to the next section. The arrows in Figure 3
show direction of current.
The various switches described, with reference particularly to Figures 3 and 4, can
be actuated by pointsmen (who would thus have complete control of the traffic), or they
could be moved mechanically by the passing cars, or magnetically, electrically, or
electro-magnetically by or from the passing cars. Thus Figure 5 shows an arrange-
ment for moving them by means of the variations of potential differance between the twin
conductors A and B produced by the presence on a section of a motor at work. When
there is no car on the section, a high resistance coil H magnetizes an electro magnet M,
and pulls in an armature which makes at C a contact through a very low resistance
coil L between A and B if adapted to Figure 3, or between two consecutive sections
of B if used with Figure 4. When this contact is made, almost no current flows
through H (if preferred it may be broken altogether), but the influence of L is just
enough to retain the armature and its contact. When a motor as shown begins to
take current, it reduces the current in L, the armature lets go, and A and B are
connected only through H and the motor coils. When the car runs off the section,
H again pulls the armature and remakes L.

page_text: When the switches cannot conveniently be exposed, as for example in street tramway
work, the moving energy may be transmitted from the car through a momentary
contact suitably established between a source of energy on the car (which source may
be the motor driven as a dynamo by the momentum of the car, or may be storage
cells, or other) and a conductor on the road, arranged so as to lead this energy to an
electro-magnetic switch in a channel or box underneath the road or elsewhere; or the
now well-known device of an electro magnet on the car, transmitting its magnetism
through an iron conducting piece to the concealed switch. Or the car may make a
contact which diverts momentarily a fraction of the working current, or checks a
pre-existing diversion of current to an electro magnet arranged so as by its action to
make the desired connections; and on going off the section it may again suitably
change the switch or switches by reversing or repeating the impulse. The switches
can also be made in a manner easily understood by any electrical engineer, to connect
and disconnect certain sections of contact conductor where such contact conductors
are provided on to or off from the more carefully insulated main circuit, thus
reducing the need for good insulation of the contact conductors by separating them
from the circuit save when current was needed at the places where these were.
Wherever it is practicable, 1 prefer that the switches if not attended to by points-
men, be moved mechanically, or electrically from the car rather than by the balance
of potentials, or that at least the switches or contacts which may be used to send
current to work the connecting switches be so moved. Thus, in illustration of how
the changing switches as described can be worked by means of current passed through
them from or by means of the car :-Let there be an electric street tramway system
arranged in sections of 100 yards in length. Plain strong electro-magnetic water-
proofed changing switches as at S, S, Figure 3, or S, S', S, Figure 4, are placed in
watertight cast-iron boxes having hinged lids flush with the street and situated
preferably just where two sections meet, that is to say, at every 10 yards. The
electro magnetic switches may be of any common construction; for example there
may be two bobbins with cores, and when a current goes through one bobbin an
armature is pulled in one way thrusting metal joining plugs between contact springs,
and when current goes through the other the armature is pulled the other way and
the metal joining plugs are withdrawn, or one magnet may drive a lever alternately
in opposite directions by the successive pulls of its armature, and so on. These switches
when they change to the position they occupy when a car is on their section, may
when an open slot channel is objectionable also or only connect the well insulated
conducting wires with say the rails on which the cars run. These rails would be crudely
insulated from each other and from the rails of the preceding and succeeding sections
and would then fulfil for the time the functions of conductors A and B in Figures 3 or 4.
The motor car would collect the current from these rails in the usual manner. The
current to actuate these switches could be derived from a generator on the car or
elsewhere, and one or a pair of contact arms projecting from the car would be used to
close their circuit. They would do this by coming in contact with one or more blocks
of metal or other conductor, as for example, the iron covers of two boxes sunk in the
street, or conducting blocks carried on posts placed 100 yards apart, or suspended
from a high stayed wire overhead, such conducting blocks being permanently joined
electrically to the terminals of the electro magnet switch.
It is often a safeguard against accident to so connect some section preferably a
short special section near the termini that (unless the driver is alert to change a switch
on the car) the current is reversed and brakes put on automatically when the car runs
on to such special section. It might thus be made safe to have only one driver even on
high speed trains.
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. An electric railway series system having double sectional conductors running
side by side, the sections being of such length and so arranged that the core can
rnn

page_text: along them in approximately equal times, the motor cars being numerically equal to
the number of gaps in the twin conductor, substantially as described with reference
to Figures 1 and 2 of the accompanying drawings.
2. In an electric rail or tramway, a system of double sectional conductors in which
the connections between sections are so made that the current through the rubbing or
rolling contacts of the car flows in one uniform direction instead of reversing its
direction when the car passes from one section to another, and particularly as described
with reference to Figures 2 and 4 of the accompanying drawings.
3. In an electric rail or tramway the combination of double sectional conductors
with switches which open when a motor is on or drawing current from a section, and
close when the motor ceases to draw current, substantially as described with reference
to Figures 4 and 5 of the accompanying drawings.
4. In an electric rail or tramway system, an automatic switch, substantially as
described with reference to Figure 5 of the accompanying drawings.
5. In an electric street tramway series system having double sectional conductors,
the device of working an electro-magnetic changing switch by means of current
supplied from a generator on the car, or otherwise, and that through a conductor
arranged so as to be touched in passing by a contact piece carried by the car.
6. In an electric railway, the device of so joining up the conductors at certain
positions, say at every change of section or only near the termini of the line, that the
current in the motor would be reversed, and also, if desired, that the brakes would
be applied by that reversal whenever the train touched the section unless the driver
was alert to prevent the reversal of motor by moving his car switch, substantially as
described.
Dated this 24th day of July 1890.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.