Improvements in or in connection with Means for Supplying Current to Electrically Propelled Vehicles.
Year: 1899

page_text: Date of Application, 6th June, 1899-Accepted, 23rd Sept., 1899
COMPLETE SPECIFICATION.
Improvements in or in connection with Means for Supplying Current
to Electrically Propelled Vehicles.
I, HENRI DOLTER, of 41, Rue Taitbout, Paris, France, 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 a new method of supplying in underground conduits
current for electric traction.
This system is principally characterised by the four following arrangements,
namely:-
1. A series of similar contacts each formed of two magnetic parts separated
by a non-magnetic piece.
"
2. A balanced contact supported by the magnetic pieces which allows of arc
ruptures of any required length being obtained.
ה
3. A special method of connection with the underground conductor at each
contact.
4. A suspended brush beneath the vehicle consisting of two flexible longitu-
dinal bars provided with cross pieces and electro magnets which induce in each
of these bars a different polarity; each bar touches one of the two magnetic
parts in such a manner as to close the magnetic circuit through the soft iron
of the balance and this with a minimum of gap.
This invention is represented in the accompanying drawings in which
Figure 1 is a section on the centre of a contact taken perpendicularly to the
track.
Figure 2 is a section at right angles to the preceding and consequently
parallel to the rails.
Figure 3 is a diagram showing the path of the current in the electric circuit.
In these figures :-
A A' are the two magnetic parts, each shown as semi circular, but they may
be of any other suitable shape.
B is the non-magnetic piece separating them. Beneath the parts A A¹ is
fixed, by means of a screw or otherwise, a cylindrical box C of porcelain or
other insulating material.
Between the parts A. A¹ and the box is placed an elastic washer.D) of leather,
lead, or other substance making a tight joint.
The bottom of the box C is centrally pierced with a hole and is provided
with concentric rings e as in bell insulators.
Beneath the parts A and A' is a carbon support E on which the balance F
oscillates; the long arm of the balance is bent and is provided at the bottom
with a highly conductive carbon bob f.
:.
This long arm consists of a glass tube f inside which is a fusible wire and
talc or insulating powder.

page_text: One end of the short arm carries a cylinder G of soft iron, which when
attracted by the magnetic parts A and A¹, enters a cavity formed in these parts
as is shown in Figure 2.
The two trunnions of the balance F which take into holes in the support E
are also of carbon.
In the box C is arranged a suitably bent conductor H, provided with a
threaded end which passes through the hole at the bottom of the box C;
upon the thread his screwed a screw cap I, separated from the bottom of the
box C by an elastic washer i thus making a joint. At the other end of the
conductor H, a carbon cube J is placed which is provided with a cavity in
which the bob f lodges.
The bottom of the box is coated with a layer K of resin or other analogous
material.
The box C and the parts A A' form together a stationary whole.
The parts A A¹ are pierced with a certain number of holes for receiving
screws for fixing them to the non-magnetic ring L which is embedded in the
asphalte concrete cylinder M.
This cylinder is supported on a cement tube m.
In the tube m is a lateral slot m¹ for giving passage to the wire o connected
to the electric main P by means of a junction box p containing a fuse.
The other end of the derived circuit 0 is provided with a cap Q, forming a
bell insulator of ebonite or other insulating material: the cap has upon it
rings taking into the rings c of the box C as seen in Figures 1 and 2.
R is a double union soldered on the derived circuit and screwing onto the
piece I.
Care should be taken to coat the recesses in the bell insulator with vaseline
or a solid grease.
Under the vehicle to be propelled is suspended a brush insulated from the
vehicle.
This brush is composed of two iron bars T T¹ connected together from dis-
tance to distance by cross pieces upon which an insulated copper wire is
wound thus forming an electro magnet U. One end of the insulated copper
wire of the electro magnets is connected to one of the two bars T or T¹ (in
the drawing the bar T¹) and the other end to the terminals of the regulators
(corresponding to those of the trolley of an aerial line) marked 3 in the
drawing.
It is best to explain the action of the system with reference to Figure 3 of
the accompanying drawing in which the same letters designate the same parts
as in Figures 1 and 2. N and S indicate respectively north and south polarities.
In order to explain the action of the system I make mention of certain
parts and arrangements forming no portion of this invention and which are
designated by figures in the description.
A vehicle equipped in such a manner as to be propelled on the trolley system,
carries moreover a brush T T¹ and a small battery of accumulators 1, the posi-
tive pole of which is connected to one of the bars of the brush and the negative
to a contact 2 of the regulator in such a manner that the battery 1 is put in
the circuit of the electro magnets U, by short circuiting the contact 2 with
the contact 3, only when the vehicle is in motion and is put out of circuit
when it is desired to stop the vehicle or to put on the break by transforming
the motors 4 into generators. The contact 3 corresponds to the terminals of
the regulators of the trolley of an aerial line.
The number of elements is calculated in such a manner as to obtain in the
winding of the electro magnets exciting the bars T T a number of ampère
turns sufficient to attract the armature G at any speed.
The resistance of the winding is also calculated in such a manner that in
daily work the power absorbed by the battery is in excess of that required to
be given out so that no thought need be taken to always have an excess.

page_text: This arrangement also allows a very small difference of potential to be main-
tained between the bars and the other end of the exciting wire.
At both ends of the vehicle are two metallic brushes 5, 5 electrically con-
nected to the wheels in such a manner as to short circuit the contact box A A¹
when the part G does not fall back.
This short circuiting causes fusion of the wire in the tube, the rupture of
the glass tube f¹ and breaks the derived circuit.
The return of the current to the generator takes place by the rail 6.
The vehicle is lit by two sets of lamps, the one 7 in series with the main
circuit, the other 8 in parallel with the battery 1.
The switching between these two sets of lamps takes place by means of an
automatic circuit breaker 9 of any usual construction which allows the vehicle
to be automatically lit when in motion by the lamps 7 and by the lamps 8
when at rest.
When therefore the vehicle, equipped as described, is placed on a track having
the magnetic contacts A. A¹ arranged at distances apart less than the length of
the bars placed beneath the vehicle, and one of the handles of one of the
regulators is turned, the accumulators 1 are placed in series with the winding U,
and the two bars T T¹ each acquire throughout their length a different polarity,
T being of north polarity and T¹ of south and communicate this excitation to
the two pieces A A' which attract the armature G as shown in dotted lines
in Figure 2.
The bob becomes lodged in the cavity of the cube J, the pressure on these
two parts being regulated by the distance between the armature G and the
parts A A
The length of the long arm or glass tube fl is calculated in such a manner
as to obtain a rupture sufficient to insure there being no arc whatever the
quantity and tension of the current may be.
At this moment the circuit is closed to the motors 4 and these are put into
action.
The bars TT are soon brought by the motion of the vehicle to the next
metallic contact at which the same operation of closing the metallic circuit
takes place as the vehicle advances, the bars leave the preceding metallic con-
tact the soft iron piece G of which being no longer attracted by A. A¹ falls
causing the bob f to assume the vertical position shown in full lines in
Figure 2.
The contact is therefore again insulated from the electric main.
If for any cause the piece G does not fall, the brush 5 will close a short
circuit through the contact which will cause the fusible wire to fuse, the rupture
of the tube f and the fall of the bob f.
Of course the details of construction and the arrangement of the apparatus
herein described may be modified and I do not limit myself to any shape of
contact.
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. A contact formed of two magnetic parts separated by a non-magnetic
piece.
:
2. In a contact formed of two magnetic parts as above the combination of a
box of insulating substance containing an armature in the form of a beam of
a balance the short arm of which carries a piece of soft iron, and the other,
suitably bent, a carbon bob which when the soft iron piece is attracted abuts
against a piece of carbon in permanent contact with the underground working
conductor.
3. The system of junction with the working conductor by means of a double
bell insulator substantially as described and shown in Figures 1 and 2.

page_text: 4. The combination with a vehicle of a brush suspended under the vehicle
consisting of two longitudinal flexible bars connected by cross pieces upon
which insulated copper wire is wound which being traversed by an electric
current strongly excites the two bars and communicates to one of them.
throughout its whole length a north polarity and to the other also throughout
its whole length a south polarity as above described.
5. In a vehicle carrying a battery of accumulators for operating contact
mechanism for supplying current from a main circuit conductor to a motor
on the vehicle the combination of a set of lamps in parallel in a circuit from
said battery and of another set of lamps in series on the main circuit to the
motor and means for automatically switching the lamps in the battery circuit
out of action when current is passing to the motor and the lamps in series
with it.
6. The novel method of supplying in underground conduits current for
electric traction substantially as described and illustrated in the accompanying
drawings.
1