Improvements in Electrical Traction on the Closed Conduit System.
Year: 1899

page_text: Date of Application, 20th Dec., 1899
Complete Specification Left, 20th Sept., 1900-Accepted, 15th Dec., 1900
PROVISIONAL SPECIFICATION.
Improvements in Electrical Traction on the Closed Conduit System.
I, HOWARD LANE, of Princes Chambers, Corporation Street, Birmingham, in
the County of Warwick, Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention has reference to systems of electrical traction known as the
conduit surface contact or underground types, and is of particular importance in
the case of electrical tramways and light railways. It consists in the improve-
ments hereinafter described in the electrical distributing conductor or conductors
or cable or cables; the arrangement and the means for laying it or them; devices
for bringing it or them into active communication with electrical motor apparatus
arranged upon the cars or carriages; and a method of ensuring a good and active
working of the said conductor or conductors and devices at all times.
According to this invention a flexible distributing electric conductor or cable
is placed within a closed air-tight conduit or pipe disposed within the ground
between, or adjoining, the rails of a track. This conductor or cable, in the case
of metallic conduits, normally rests upon earthenware or other insulating blocks
disposed within the conduit along the bottom and sides, and is of such construc-
tion and formation as to be capable of flexing or bending sufficiently into a curve
at any portion of its length when said portion is lifted up from its insulated
seating. The said conductor or cable is preferably of a thin strip section, and
is of soft iron or such other material capable of magnetization to form a good
carrier for electrical current. The conductor may be coated with a metallic
material to prevent its oxidation and to ensure efficient electrical contact. This cable
runs the whole of the length of the track and is laid within the conduit suffi-
ciently free to enable portions of it to be lifted as before described. It may be
formed with folds or loops, so that it is capable of expansion or contraction with-
out disarrangement of its function.
The conduit is an air-tight trough or pipe running the full length of the track.
and is hermetically sealed or closed and formed in sections which may be joined
terminally with insulating material and laid in an excavation below the ground
surface.
The insulating blocks, which are preferably of a shallow trough section, fit
within the bottom of the said conduit and preferably have ridges or intermediate
points of contact for the electrical conductor or cable to normally rest on. The
conduit may be either of non-conducting material or metal. The insulating
blocks insulate the conduit from the conductor or cable. The conduit is built
in the ground and is surrounded with ashphalte or other insulating material,
which ensures absence of earth connection.
One of the essential features of this invention is the use within the closed
conduit containing the conductor or conductors of a gas low in oxygen or a gas
which does not contain free oxygen, such, for example, as coal-gas carbonic oxide,
or hydrogen, which will have the effect of reducing metallic oxides to their
normal metallic conditions. The presence in the conduit of such a gas, or

page_text: reducing agent, prevents oxidation and corrosion of the relative contact surfaces
of the conductor or conductors and the pole pieces or electrical junction pieces or
conductors, so that a perfect and active working between these parts at all times
is ensured.
Inserted within the top of and secured to the conduit at distances apart for its
entire length are a number of sockets or ferrules of insulating material, and
arranged within each socket or ferrule is a soft iron pole piece or electrical
junction piece or conductor, of such a length as to project at one end into the
conduit, to within a certain distance of the conductor or cable already described,
and at the other end to project slightly above the ground surface.
Upon the car or vehicle is provided one or more magnets, preferably of the
electro type, which, in the passage of the car over the pole pieces, excite them
progressively sufficient to cause them to attract the charged. main conductor or
cable and lift it from its insulating seating to make electrical contact with the
inner ends of the said pole pieces, the said main conductor or cable ascending.by
magnetic attraction to each pole piece, as the car or carriage proceeds over it,
in a wavelike and undulatory fashion. The poles proper of the magnets may
be constructed as metallic brushes and form the collectors of the power to feed
the motors on the car or carriage, or an independent collector having a brush
contact may be provided to wipe over the pole pieces. Instead of a brush
collector a sleigh runner contact may be arranged, having a rubbing effect.
Another of the essential features of this invention is to provide upon the car
or carriage means for dealing with any residual magnetism in the pole pieces
after the magnets on the car have passed over and left them, such residual
magnetism being liable to continue to hold up to the pole pieces the conductor
or cable. To effect this I preferably provide upon the car, rear of the magnets
proper, a secondary magnet, either electro or permanent, presenting to the pole
pieces one only of its poles. The presented pole of this secondry magnet is of
an opposite sign to the trailing pole of the main electro magnet, so that it is of
a like sign to the upper ends of the pole pieces as it passes over them, which has
the effect of either dispersing the residual magnetism in the pole pieces or of so
changing it that the said pole pieces will repell the said conductor or cable. If
this secondary magnet is an electro magnet it is constantly energised.
By the use of two such conduits as described the electric current may be
conveyed to and from the vehicle or carriage without any necessity for bonding
rails.
-
With the improvements hereinbefore defined a simple and efficient system of
electrical traction can be put down at a comparatively small cost, and with a
minimum of interference with road surface and traffic.
Dated this 19th day of December 1899
W. P. THOMPSON & Co.,
11. Burlington Chambore Now Street, Birmingha
Patent Agents for the Applicant.
Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Electrical Traction on the Closed Conduit System.
I, HOWARD LANE, of 6, Corporation Street, Birmingham. in the County of
Warwick, Engineer, do hereby declare the nature of my said invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement, and accompanying drawing, that is to
say:
My invention relates more especially to the systems of electrical traction known

page_text: as conduit surface contact, or underground types, and it is particularly applicable
to the case of electric tramways and "light" railways.
This system is distinguished by the fact that the tube or conduit in which a
main electric conductor is placed, is arranged at a short distance below the sur-
face of the road, and is completely closed, the communication with the electric
motor upon the car (by which the latter is propelled) being effected not through
a continuous slot or opening along the upper side of the tube or conduit, as in
some other systems, but by means of a series of exterior surface magnetic pieces
insulated from each other, over which the poles of an electro-magnet carried by
the car pass and serve to magnetize the surface magnetic pieces or rails in succes-
sion as it passes over them, their lower sides when so magnetized attracting and
raising into contact with them the flexible electrical conductor in the conduit,
the electricity from which accordingly passes to the surface magnetic pieces, from
which it is collected and led to the electro-motor on the car, the return current
being through the main rails or through a conductor similar to that described
to the electrical supply station.
Apparatus, however, constructed and used according to this system of electrical
traction, has been found open to serious objections, and has not heretofore come
into practical use, the electrical conductor or conductors, or cable or cables, and
the arrangement and means for laying it or them, and the devices for bringing
it into active connection with electro-motor apparatus arranged upon the car or
carriages, being expensive, difficult to properly lay and arrange in the first
instance and liable to get out of order, whilst not always working perfectly satis-
factorily, and frequently failing when in operation, the contact surfaces of the
conductor or conductors and of the surface magnetic pieces or rails contained in
the conduit, being very liable to oxidation and corrosion by the passage of the
electricity between them, so that the passage of the electric current to the motor
is no longer assured.
By my present invention, these difficulties and objections are overcome, and
the entire apparatus rendered very simple, economical, durable, and effective, a
good and active working of the conductor or conductors and other devices being
at all times assured, accompanied by facility for installation without disturbance
of old lines, non-interference with gas and water mains, and ready passage over
existing bridges.
The system constructed according to my invention consists essentially of a
distributing electric conductor or cable, sufficiently flexible vertically, placed
within a closed air-tight conduit or nipe disposed in the ground between or
adjoining the rails of a track. This conductor or cable, in the case where a
metallic conduit is used, rests normally upon earthenware or other insulating
blocks or supports, preferably of a shallow trough-like section, arranged in the
conduit along its bottom and sides, and the conductor is of such construction and
formation as to be capable of flexing or bending up sufficiently, into a curve, at
any part of its length, when such part is lifted up from the seating formed by
the insulating blocks or supports. The flexible conductor or cable is preferably
in the form of a thin strip in cross section, and is of soft iron or such other
material as may be capable of magnetization, and of forming at the same time
a good carrier or conductor for electrical current. The conductor may be coated
with a metallic material in order to prevent its oxidation and to ensure efficient
conduction, and good electrical contact with the surface magnetic pieces, or pole
pieces, hereinafter described. The flexible conductor or cable is laid within the
conduit sufficiently freely to enable parts of it to be lifted somewhat as before
described.
It may, if necessary, be provided with folds or loops or equivalent devices, so
that it may be capable of sufficient expansion or contraction without interfering
with its function, or preventing it from bending up sufficiently. The conduit in
which the conductor is laid is an air-tight trough or pipe, preferably of more or
less rectangular section, running the full length of the track. It is hermetically

page_text: sealed or closed, and is formed in sections or lengths which are jointed together
on the spigot and socket principle, the joint being of insulating material. The
conduit is made of a non-magnetic alloy or material, so that the field of a magnet
moving over it is not materially weakened, and it is carefully laid in the ground,
its upper surface being just below the road level, and is preferably surrounded
with asphalt or other insulating material, which prevents liability to earth
connection.
The upper longitudinal surface of the conduit, pipe, or trough described, is
provided at regular distances apart, and at frequent intervals for its full length,
with dove-tailed or other shaped sockets or recesses, into each of which is fitted
a soft iron "
pole piece" or electrical junction piece or conductor, of such length
that its lower end or face projects down into the conduit to within a certain short
distance of the flexible conductor, whilst its upper end or face (which is only of
short length) projects upward level with or slightly above the road surface. The
pole-piece is provided with a shoulder which rests upon an electrically insulating
washer at the bottom of the socket, and it is firmly secured in the latter with
electrically insulating cement so that it is entirely insulated from the conduit.
The flexible conductor is supplied with electrical current at intervals through
flexible or other connections from the distributing electrical mains or feeders.
In order to collect electricity from the flexible conductor described and supply
it to the motor on the car or carriage, the latter carries underneath its body one
or more magnets and collecting brushes or skate runners. The magnet may be
permanent, but it is preferably an electro-magnet (which may be initially excited
by a small galvanic battery, but when once excited is sustained by a shunt off
the main current). When the car is travelling, as the magnet passes above the
upper ends of the pole pieces it excites or magnetizes them sufficiently to cause
them to attract the charged flexible main conductor in the conduit, and draw or
bend it up from the insulated blocks or supports which form its seating, sutli-
ciently for it to make electrical contact with the inner or lower ends of the pole-
pieces.
The poles proper of the magnet or magnets themselves may be constructed in
the form of metallic brushes, which as the car travels slide or sweep over the
upper surface of the several pole-pieces in succession, or an independent collector
having a brush contact may be used to pass over the said surface of the pole-
pieces. Or a skate runner may be arranged for the same purpose, having a rub-
bing effect.
The electro-magnet presents two poles to the pole-pieces upon the upper side of
the conduit, and the face of each pole of the magnet covers or passes above at least
two of the pole-pieces at once, and these and the two poles of the magnet may be
sufficiently far apart for one or more vertical pole-pieces to be situated in the
space between them.
The accompanying drawing is in illustration of my invention. Figure 1 is a
longitudinal section through one of the pipes or conduits, Figure 2 is a transverse
section through the conduit, and Figure 3 is a transverse section through the
electro-magnet carried by the car or carriage.
The same letters of reference indicate similar parts in the several figures.
a is the distributing conductor or cable, and b is the closed air-tight conduit or
pipe, and c, c, are the insulating blocks or supports upon which the conductor rests.
d is one of the joints between two sections of the pipe or conduit b, and e, e, e, are
the dove-tailed shaped sockets or recesses, into which the pole-pieces f, f, f, are
fitted, but are kept insulated by insulating cement or material g.
The electro-magnet h carried by the car or carriage is shown having two
cores wound with insulated wire at i, as shown in Figure 3, but any convenient
form may be used.
Their poles N, S are divided so that the collecting brushes k, l, can be arranged
between them and brush over the upper surface of the pole-pieces f, the poles N, S,
passing sufficiently near to the pole-pieces to induce in them the magnetism

page_text: necessary to raise the flexible conductor a into contact with their lower ends,
electricity from the conductor then passing through the pole-pieces and the
brushes to the electro-motor on the car.
An important feature in my present invention consists in the use in the closed
conduit or pipe containing the conductor, in systems of electrical traction known
as conduit surface contact, or underground types, of a gas low in oxygen, or a
gas which not only contains no free oxygen but has chemical affinity for oxygen
such for example as coal gas, carbonic oxide, or hydrogen, which will have the
effect of reducing metallic oxides to their normal metallic condition.
The
presence of such a gas or reducing agent, prevents oxidation and corrosion of the
respective contact surfaces of the conductor or conductors and of the pole-pieces
or electrical junction pieces or conductors with which they come in contact, and
through which electricity from the conductor passes, so that a perfect and active
electric contact and working between these parts is at all times ensured.
It will be obvious that, by the use of a second conduit such as that described,
the tram rails themselves need not be used for the return current, they need not,
therefore, be bonded or disturbed, and existing roads can be converted to my
improved system without stoppage of traffic or interference with rails.
The operation of the system is as follows:-The car being placed upon the
line and the conductor charged, the electro-magnet is initially excited, and the
flexible conductor at once rises from its insulated supports, and makes electrical
contact with the lower end of the pole-pieces, from the upper surface of which
the brushes or collectors draw the current. The magnet being wound with fine
wire, and provided with suitable resistance, only sufficient current flows round
it to maintain it in an excited condition. The motor on the car is set in motion,
regulated, and controlled in the well-known way, by the driver.
The arrangement of pole-pieces and magnets described ensures the destruction
of all residual magnetism (if there should be any) in the pole-pieces in the trail
of the magnet, each receding pole-piece being instantly demagnetized by the
induction of its preceding and more powerfully magnetized neighbour.
tendency of the flexible conductor to adhere to the pole-pieces after the car has
passed, is therefore removed.
All
For additional security, however, I sometimes provide upon the car or carriage
means for dealing with any such residual magnetism in the pole-pieces after the
magnet or magnets on the car have passed over and left them. To effect this, I
preferably provide upon the car, at the rear of the magnets proper, a secondary
magnet either electro- or permanent-presenting to the pole-pieces one only of
its poles. The pole of this secondary magnet so presented is of the opposite sign
to, but considerably weaker than the rear or trailing-pole of the main electro-
magnet, so that it is of the like sign to the upper ends of the pole-pieces as it
passes over them.
This has the effect of either neutralizing the residual
magnetism in the pole-pieces or of so changing it that the said pole-pieces will
repel the flexible conductor or cable from their lower ends. If an electro-magnet
be used for this secondary magnet, it is kept constantly excited.
It will be seen that by the novel details of construction and arrangement described.
the only parts exposed on the surface of the road are the small rectangular faces
of the upper ends of the pole-pieces, which are at regular distances apart, and
absolutely free from electricity except at the time when the magnet upon the
car is passing over them.
There is, therefore, no danger in the use of my improved system, the separate
insulated pole-pieces being absolutely dead and neutral as soon as the car has
passed, without any possibility of electricity being then communicated from them
by accidental or other contact with their small upper surface, which constitutes
the only part of the entire system which is exposed or visible at or above the
surface of the roadway.
I do not confine myself to the precise form and proportion of the parts of
apparatus made under my improved system, nor to the precise method of con-

page_text: struction and arrangement, which may be varied more or less to suit varying
circumstances, nor do I claim the use of a flexible conductor or the use of electro-
magnets on the car influencing the flexible conductor as they pass along it, but,
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:―
1. The combination of a flexible electric and magnetic conductor a, insulating
supports c, contained in a conduit or pipe b, having sockets or recesses e, at
regular distances apart, containing insulated soft-iron pole-pieces f, substantially
as described and illustrated.
2. In combination with the flexible electric and magnetic conductor a,
insulating supports c, contained in a conduit or pipe b, having sockets e contain-
ing insulated soft-iron pole-pieces f, as described and claimed in Claim 1, the
electro-magnet h carried by the car or carriage, having poles N, S, one consider-
ably in advance of the other, and passing, when the car is travelling, at a short
distance above the pole-pieces f, and each of sufficient length to extend above at
least two of the pole-pieces at once, and brushes or collectors k, l, by which the
electricity is collected from the upper surface of the pole-pieces, and is led from
them to the electro-motor of the car or carriage, substantially as described and
illustrated.
3. In combination with a flexible electric and magnetic conductor, separate
insulated soft-iron pole-pieces, excited by the passage above them of a magnet
carried by the car or carriage, and collectors for collecting electricity, from
the upper surface of the insulated pole-pieces, a secondary magnet upon the
car or carriage, presenting to one of the insulated pole-pieces below, one of its
poles of like sign to the upper ends of the pole-pieces, for the purpose of dis-
persing any residual magnetism in the pole-pieces, and preventing the continued
attraction of the flexible conductor, substantially as described.
4. In systems of electrical traction known as conduit surface contact, or under-
ground types, the method of keeping the closed conduit or pipe, containing the
conductor constantly filled with a gas low in oxygen, or which does not contain
free oxygen, or which has a chemical affinity for oxygen, for the purpose of
preventing oxidation and corrosion of the surfaces of the conductor and of the
pole-pieces, substantially as described.
1000
Pated this 20th day of September 1000.
EDWARDS AND Co.,
Chartered Patent Agents,
65 and 66, Chancery Lane, London, Agents for the Applicant.