Improved Means of Working and Supplying Current to Electric Tramways and Lifts.
Year: 1895

page_text: Date of Application, 26th Feb., 1895
Complete Specification Left, 25th Nov., 1895-Accepted, 26th Feb., 1896
PROVISIONAL SPECIFICATION.
Improved Means of Working and Supplying Current to Electric
Tramways and Lifts. •
SEBASTIAN ZIANI DE FERKANTI, 27, Charterhouse Square, in the County of
London, Electrician and Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention has for its object improved means of feeding the conductors,
(overhead or underground) with current derived from a high tension source after
transformation, and generally supplied from a station supplying current for other
purposes, such as electric lighting.
The current required for feeding electric tramcars or electric locomotives' or
trains is, on account of the nature of the work, very variable. So much so is this
the case that it is commercially impracticable to supply light and tramways from
the same source of current on account of the variation produced in the light
thereby. In order to overcome this difficulty I feed the conductor by means of
current derived from a dynamo driven by an electro motor. Upon the shaft of
this combination I place a heavy flywheel and run the machine at as high a speed
as possible in order to store the largest possible amount of energy in the wheel.
By this means the largest variation of current taken out of the dynamo can only
produce a very gradual rise or fall in the speed of the motor, and consequent
power taken thereby. The machines at the generating station have thus time to
respond to the gradual demand without causing an appreciable variation in the
electro motive force of the supply from the omnibus bar.
In order to run the heavy Hy wheel satisfactorily and without waste of power,
it is desirable that it should be supplied with some form of antifriction bearings
besides those provided for its guidance. These anti-friction bearings may be
formed of balls or rollers of any of the well-known kinds, or any similar device
capable of producing the desired result.
The motor transformers thus constructed may be arranged to transform from
alternating to continuous current, from continuous to continuous currcut, or from
alternating to alternating current.
They may transform from one electro motive force to another up or down, or
perform any of the transformations which such a combination is capable of. They
may also be used for feeding motor or other circuits where the demands are
irregular or sudden and where it is desired not to interfere with the regularity of
the primary supply.
The method in which I consider my invention most usefully carried out is as
follows-
Where a tram-line has to be supplied with current from a station already
generating alternating high pressure current for feeding electric lamps and other
purposes for which a supply station is used, I place motor transformers with heavy
flywheels as already described, at various points along the tramline which has to
be fed with continuous current. These motor transformers take the high pressure
alternating current and transform it into low pressure continuous current of from
200 to 500 volts tension. This current is fed to the cars according to any of the
well-known methods. The energy stored up in the fly wheels of the motor
transformers supply the power for any sudden or abnormal demand, they being

page_text: the local storers of energy for the purpose. The pressure at the generating
station therefore remains unaffected and a satisfactory service can be given for
lighting at the same time that the tramcars or electric locomotives are supplied.
In some cases where existing railways or tramways are supplied with continuous
current of about 500 volts pressure and where there is considerable drop in the
feeders and variations of pressure owing to the sudden demand put upon them by
the varying conditions of the load, I place continuous current dynamos, fitted
with extremely heavy fly wheels, running at a high speed as above explained for
the motor transformers. The action of this piece of apparatus is to take current
to drive them up to their normal governing speed so long as the electro motive
force on their particular section of the road is maintained at or above its normal
amount, but when the electro motive force falls owing to any sudden demand such
as that on the passing or starting of a train being put upon that section of the
line, the stored energy in the heavy wheel drives the dynamo which then becomes
a generator and feeds back current to the line at the point where it is required,
this relieving the generating machinery at the station, and the supply mains.
In some cases where lifts are required to be driven by means of the current at
the various stopping stations along the electric line I use the above storers of
energy to supply the motors for the lifts at the same time that they supply
the line.
Or in some cases I may use the storers of energy either through an electric
clutch worked by Foucault currents, or a friction clutch or some such device, to
furnish the necessary power to the lift during the time that it is required, and
so relieve the station of the sudden strain as they absorb energy and store it in the
wheels during the times that the lifts are not running.
I may also use the motor generators which may be placed at the various stations
for supplying the lines, to act in the same way as the fly wheel dynamos for
supplying power direct to the lifts through some form of clutch gear, at the same
time as they store the energy and give the transformed supply to the electric line
for running the train.
These storers of energy may thus be usefully combined for maintaining the
pressure on the line which runs the clectric trains and also for supplying the
necessary amount of power for the intermittent service of the lifts or elevators.
Dated this Twenty-fifth day of February One thousand eight hundred and
ninety-five.
Improved Means of Working and Supplying Current to Electric
Tramways and Lifts.
SEBASTIAN ZIANI DE FERRANTI, 27 Charterhouse Square, in the County of
London, Electrician and 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 has for its object improved means of feeding the conductors,
(overhead or underground) with current derived from a high tension source after
transformation, and generally supplied from a station supplying current for other
purposes, such as electric lighting.
The current required for feeding electric tramcars or electric locomotives or
trains is, on account of the nature of the work, very variable. So much so is this
the case that it is commercially impracticable to supply light and tramways from
the same source of current on account of the variation produced in the light
thereby. In order to overcome this difficulty I feed the conductor by means of

page_text: current derived from a dynamo c Figs. 1 & 2 driven by an electric motor a
Figs. 1 & 2. Upon the shaft e Figs. 1, 2 & 3 of this combination I place a heavy
fly wheel b Figs. 1, 2 & 3, and run the machine at as high a speed as possible in
order to store the largest possible amount of energy in the wheel. By this means
the largest variation of current taken out of the dynamo c Figs. 1 & 2 can only
produce a gradual rise or fall in the speed of the motor, and consequent power
taken thereby. The machines at the generating station have thus time to respond
to the gradual demand without causing an appreciable variation in the electro
motive force of the supply from the omnibus bar.
In order to run the heavy fly wheel b Figs. 1, 2 & 3 satisfactorily and without
waste of power, it is desirable that it should be supplied with some form of
antifriction bearings d Figs. 1 & 2, besides those provided for its guidance. These
antifriction bearings may be formed of balls or rollers of any of the well-known
kinds, or any similar device capable of producing the desired result.
The motor transformers thus constructed may be arranged to transform from
alternating to continuous current, from continuous to continuous current or from
alternating to alternating current.
They may transform from one electro motive force to another up or down, or
perform any of the transformations which such a combination is capable of. They
may also be used for feeding motor or other circuits where the demands are
irregular or sudden and where it is desired not to interfere with the regularity of
the primary supply.
The method in which I consider my invention most usefully carried out is as
follows
Where a tramline has to be supplied with current from a station already
generating alternating high pressure current for feeding clectric lamps and other
purposes for which a supply station is used, I place motor transformers with heavy
flywheels as already described, at various points along the tramline which has to
be fed with continuous current. These motor transformers take the high pressure
alternating current and transform it into low pressure continuous current of from
200 to 500 volts tension. This current is fed to the cars according to any of the
well-known methods. The energy stored up in the fly wheels of the motor
transformers supply the power for any sudden or abnormal demand, they being the
local storers of energy for the purpose. The pressure at the generating station
therefore remains unaffected and a satisfactory service can be given for lighting at
the same time that the tram cars or electric locomotives are supplied.
In some cases where existing railways or tramways are supplied with continuous
current of about 500 volts pressure and where there is considerable drop in the
feeders and variations of pressure owing to the sudden demand put upon them by
the varying conditions of the load, I place continuous current dynamos, fitted with
extremely heavy fly wheels, running at a high speed as above explained for the
motor transformers. The action of this piece of apparatus is to take the current
to drive them up to their normal governing speed so long as the electro motive
force on their particular section of the road is maintained at or above its normal
amount, but when the electro motive force falls owing to any sudden demand such
as that on the passing or starting of a train being put upon that section of the
line, the stored energy in the heavy wheel drives the dynamo which then becomes
a generator and feeds back current to the line at the point where it is required,
thus relieving the generating machinery at the station, and the supply mains.
In some cases where lifts are required along the line 1 may use the storers of
energy either through an electric clutch worked by Foucault currents or a friction
clutch or some such device, to furnish the necessary power to the lift during the
time that it is required, and to relieve the station of the sudden strain as they
absorb energy and store power in the wheels during the times that the lifts are not
running.
I may also use motor generators which may be placed at the various stations for
supplying the lines, to act in the same way as the fly wheel dynamos for supplying

page_text: power direct to the lifts through some form of clutch gear, at the same time as
they store the energy and give the transformer supply to the electric line for
running the train.
These storers of energy may thus be usefully combined for maintaining the
pressure on the line which runs the electric trains and also for supplying the
necessary amount of power for the intermittent service of lifts or elevators.
In all cases the storers of energy must have sufficient weight and speed of
flywheel to give the necessary supply of current to the electric trains or tramcars
without detrimentally affecting the regularity of the lighting supply from the
station.
It is also desirable to employ a non-synchronous electric motor in the motor
transformers that will allow a fair variation of speed without too great a flow of
current taking place through the motor.
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 system of supplying current to tramways and railways substantially as
described.
(2) The system of working lifts substantially as described.
(3) The system of supplying railways and tramways with electric power from
electric light stations without interfering with the regularity of the lighting service
substantially as described.
(4) My improved means of working tramways and lifts substantially as
described.
(5) The combination of an alternating supply station feeding electric lamps in
parallel through transformers; with a system of electric tramways or railways
worked by continuous current supplied from motor transformers, which transformers
are so constructed as to store a large amount of mechanical energy so as to meet a
sudden demand without a sudden load being thrown on the generating station.
(6) Working electric railways with the interposition of a considerable storage
of mechanical energy between the generating machines and the railway so as to
take up any sudden demand for power without calling upon the generating station
in a corresponding manner.
(7) My improved form of energy storers with antifriction bearings in combination
with a heavy revolving flywheel.
Dated this Twenty-fifth day of November 1895.