Improvements in Electromagnetic Systems of Supplying Power to, and of Propelling, Railway and like Vehicles.
Year: 1894

page_text: Date of Application, 25th June, 1894
Complete Specification Left, 21st Mar.. 1895-Accepted, 1st June, 1895
PROVISIONAL SPECIFICATION.
Improvements in Electromagnetic Systems of Supplying Power to,
and of Propelling, Railway and like Vehicles.
We, JOHN PERRY, Professor of Engineering of 31 Brunswick Square London
W.C. and THOMAS TOMLINSON Electrical Engineer of 10 Pall Mall London W.C.
do hereby declare the nature of this invention to be as follows:-
In all other systems of electric traction, power is obtained by closing a conducting
circuit which connects apparatus on the car with the generator of electricity; this
necessitates actual metallic contact. In our system the power is collected from the
line wire or wires (which support or convey alternating currents of electricity) by
the closing of an open magnetic circuit (or circuits) laid along the track, by a
mass or masses of iron on which insulated wires are wound (to receive power &
give it to an electric motor or motors) carried by some or all of the cars or other
vehicles propelled or drawn. This does not necessitate metallic contact between
the moving & fixed parts of the system.
The open magnetic circuit which preferably has a core of iron of a trough or
strip or other suitable form of well divided iron may be wound so that the magnetic
force between the fixed wires, is in the direction of the track or again, at right
angles to the track or in any other direction. The fixed wire may be a broad strip
going once along the track and back again underneath or back again along a
second track alongside the first (or the return may be by "earth") or it may go
many times; or it may be wound with the planes of its coils nearly at right angles
to the direction of the track or much askew. At places where there is no car it
may be said that the magnetic circuit is open because it is only completed through
the air by a long path of considerable magnetic resistance so that there is not much
magnetic current or induction, whereas when it is completed through a mass of
iron with large polar surfaces so that the air part of the circuit is of small
resistance, the induction is great.
There may be two or more open magnetic circuits with one, two or multiphase
currents.
The mass of iron on a car may itself be the two limbs (without yoke) and
armature of the electric motor.
We sometimes vary the power by automatically or by hand altering the
resistance of the magnetic circuit-as for example, by altering the thickness or
area of the air space or spaces.
For short lines the current in the line would preferably be direct from the
alternators; in long lines it would be from transformers at suitable intervals,
with the double purpose of allowing of the use of high voltage for the long
distance transmission of energy and of permitting sections of the line not in use
to be disconnected automatically or by hand.
Dated this 21st day of June 1894.
JOHN PERRY.
THOMAS TOMLINSON.

page_text: Improvements in Electromagnetic Systems of Supplying Power to,
and of Propelling, Railway and like Vehicles.
JOHN PERRY, Professor of Engineering of 31 Brunswick Square London W.C.
and THOMAS TOMLINSON Electrical Engineer, 10 Pall Mall London W. 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:-
In all other systems of electric traction power is obtained by closing a conducting
circuit which commerts apparatus on the ear with the generator of electricity;
this necessitates actual metallic contact. In our system the power is collected
from the line wire or wires (which carry alternating enrrents of electricity) by
the closing of an open magnetic circuit (or circuits) laid along the track, by a mass
or masses of iron on which insulated wires are wonn (to receive power & give
it to an electric motor or motors) earried by some or all of the ears or other
vehicles propelled or drawn. This does not necessitate metallic contact between
the moving and fixed part of the system.
The open magnetic circuit, which preferably has a core of iron of a trough or
strip or sheet or other suitable form of well divide iron may be want so that the
magnetic force between the fixed wires is in the direction of the track or again at
right angles to the track or in any other direction. The fixed wire may be a broad
strip of metal going once along the track above iron & back again un ferneath the
iron, or back again above iron along a return track (or the return may be by earth)
or it may go many times; or it may be wound with the planes of its coils nearly
at right angles to the direction of the track or much askew. At places where
there is an ear it may be said that the magnetic circuit is open because it is only
completed through the air by a long path of considerable magnetic resistance s
that there is not much magnetic current or induction: whereas, when it is completed
through a mass of iron with large polar surfaces so that the air part of the circuit is
of small resistance, the induction is great. There may be two or more open
magnetic circuits with one two or multiphase currents. The mass of iron on the
car may he arranged as a motor which has no yoke, the buried iron becoming really
the yoke. In this case, it will be well either to place a choking coil in circuit with
the secondary (which is not only wound on the shank iron but also on the armature)
or to allow some of the induction to escape the coils of the secondary or in some
other way to arrange that the current in the armature shall not be in quadrature
with the induction.
We sometimes vary the power by, automatically or by hand, altering the
resistance of the magnetic circuit-as, for example, by altering the thickness or area
of the air spaces.
For short lines the current in the line would preferably be direct from the
alternators; in long lines it would be from transformers at suitable intervals,
with the double purpose of allowing of the use of high voltage for the long distance
transmission of energy & of permitting sections of the line not in use to be
disconnected automatically or by hand.
For the purpose of making our meaning clearer we will describe a form of our
invention with which we are now experimenting. Buried under an asphalte track
is a trough A, A of thin iron sheets of an aggregate thickness of half an inch (the
thickness depends upon the power to be collected by each car) the edges of the
plates forming the upper lips of the trough, reach the surface of the asphalte track.
The bottom of the trough is about four inches below the surface of the road. The
edges of the plates sprend out so that each lip is about 10 inches broad & additional
strips of iron are inserted there between the plates, so that on each track may be

page_text: Been two parallel bands of edges of iron plates, ench 10 inches broad & about two feet
apart. Hidden from view & inside the iron trough is an insulated strip of copper C
18 inches broad and one eighth of an inch thick. The return track is similar
to this & an alternating current goes by one copper strip & returns by the other.
On a tramcar, underneath the floor & between the wheels, so that the edges may
come down quite close to the edges of the buried iron, arc sheets of iron B B of
the aggregate thickness of three quarters of an inch. Wound round these sheets
in the direction of the length of the car is an insulated conductor intended to give
power to a motor. Wherever a car may be this insulated conductor is the secondary
of a transformer, the primary being the buried conductor.
Having now particularly described & ascertained the nature of
our said
invention & in what manner the same is to be performed we declare that what we
claim is ;-
1. The use, with alternating primary currents, of an open magnetic circuit which
may be closed at any place by a inass or masses of iron wound with wires which so
receive a secondary current.
2. The use of an open magnetic circuit consisting of a primary conductor & a
core of iron fixed relatively to the track, with masses of iron & secondary coils on
the vehicle which close the magnetic circuit & so receive power.
3. The particular method of carrying out our invention with which we are now
experimenting & which we have described.
4. The use on the vehicle, of an electro-motor without its yoke as a means of
closing the magnetic circuit, in the way described.
5. The division of the line into sections, each worked by its own transformer.
6. Automatically or by hand, disconnecting any section of the line which is not
in use.
7. Automatically or by hand, altering the resistance of the magnetic circuit.
Dated this 20th day of March 1895.
JOHN PERRY.
THOMAS TOMLINSON.