IMPROVEMENTS IN DYNAMO-ELECTRIC ENGINES
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Amédeé Lalance and Maurice Bauer
at the Office of the Commissioners of Patents on the 25th September 1882.
AMÉDEÉ LALANCE and MAURICE BAUER at Paris 30 Boulevard Magenta
"IMPROVEMENTS IN DYNAMO-ELECTRIC ENGINES"
The principal object of this invention is the construction of a dynamo electric
machine which is distinguished from all existing machines of this kind by the
special form of its inducing and induced electro magnets as well as by their
manner of rotation transversely to their poles. The end we have sought to attain
was to augment as much as possible the magnetic field by the development or
extension of the poles and to bring the induced and inducing bobbins as near
together as possible
This has been attained by the actual construction of the machine which allows
of the perfect centering of the fixed and rotating inagnets besides which the
construction of the electro magnets is extremely simple and their winding may be
effected separately.
Other improvements consist in the construction and use of a novel commutator
for dynamo electric machines and in the construction and use of special inducing
bobbins for the generating machines.
In our improved machine the neutral axis is in a line passing through the centre
of the machine, currents on one side being positive and those on the other side
negative.
All the bobbins on the left for example will be traversed by direct currents
combined in tension, and all those on the right will be traversed by inverse
combined currents also in tension These currents will be collected by means of a
brush arranged in contact with a collector consisting of a metal ring or collar
mounted on and insulated from the rotatory shaft of the machine.
The machine consists of a fixed frame to which are bolted the two frames
carrying the inducing electro magnets the axes of which are parallel to the axis of
the machine and which by their construction insure the perfect cross staying of
these frames. Two supports and bearings serve to sustain the rotatory shaft on
which are keyed discs between which the induced magnets are secured so that
their axes shall also be parallel to the axis of the machine. The shaft also carries
the collector and the commutator herein after referred to.
This construction allows of the magnetic fields being as close as possible and of
considerably increasing the power of the induction currents produced.

page_text: The electro magnets are each formed of a bar of soft-iron having conical ends.
Between these conical ends the wire is wound so that the one side is positively and
the other negatively magnetised. This winding may be effected either direct or
on separate bobbins to be afterwards united. Over these bobbins is fixed a soft
iron casing partially or entirely enveloping the circumference of the bobbins nearly
up to the neutral line and forming the developed or extended poles of the
armatures.
If therefore they are mounted so that one side of the inducing bobbins is
positive and the same side of the induced negative, On the disc being put in
motion as many currents of the same direction will be produced in the induced
bobbins as there may have been interruptions. This arrangement is that which
may be adopted for continuous current machines and in this case the inducing
bobbins placed on the exterior circle will be fixed and the induced bobbins
moveable.
To obtain an alternating current machine the inducing bobbins will be moveable
and the induced bobbins will be fixed.
To this end the electro magnets fixed on the exterior circle or frame will be
placed so that the positive and negative poles alternate on the same side. The
moveable inducing electro magnets will also be placed with their poles alternating
and will be excited by a continuous current machine.
Consequently it is clear that the collected currents will be alternating and that
the bobbins may be grouped in different ways and may feed several different
regulators or lamps.
In order to obtain a rapid demagnetisation of the induced bobbin we construct it
with as thin walls as possible which in the case where the circumference of the
bobbin would be completely enveloped are further split in two in the longitudinal
direction of their axes by one or more saw cuts. We also reserve to ourselves the
right to construct them of thin discs of metal made by punching and united
together; this referring to the inducing as well as to the induced bobbins.
This machine being reversible we reserve the right to utilise it as a motor and
we maintain that the bringing of the magnetic fields so near together and the
increasing of their amplitude by the special form of our electro magnets will
produce a motor giving a result superior to all machines now in existence
To further increase the power of the machine and as much as possible to suppress
all injurious effect we make the soft iron casings of the magnets (which casings
constitute extensions of the poles of the said magnets) of such form that magnetic
contact between the inducing and induced magnets shall be broken immediately
the induced magnets are brought by the rotation of the shaft of the machine into
such positions relatively to the inducing magnets that the axes of both the said
magnets are in line with the axis of the said shaft.
For the continuous current machine we reserve to ourselves the right to either
make use of the induced current to excite the inducing bobbins by placing these
latter in the same circuit or by putting a certain number of bobbins in a derived
circuit with separate collectors which will be insulated on the side of the collector
to feed the inducing magnets or for any other purpose.
The induced bobbins may be united in tension or in quantity according to the
work that has to be done; to obtain quantity it may be useful to use the same
number of bobbins, as inductors and unite the poles of the wire of each bobbin to
the collector while to obtain tension they will be unite the one to the other.
We reserve to ourselves the right to employ any number of electro-magnets
either as inducing or induced bobbins But in order to properly distribute the
different induction currents produced we choose a different number of induction
bobbins to that of inductors.."
The commutator may be arranged on one side of the machine and the collector
on the other side, or commutators may be fixed on both sides of the machine
The said commutator is composed of a number of rings corresponding to the
number of induced or rotatory bobbins; each of these rings is in insulated

page_text: connection with an induced bobbin corresponding thereto and is at its circumference
provided with as many equi distant insulating notches as there are inducing
bobbins. Thus in a machine in which there are eleven induced and twelve
inducing bobbins eleven rings are used each one of which is provided with twelve
notches. Therefore the commutator is provided with eleven times twelve or one
hundred and thirty two notches producing one hundred and thirty two inter-
ruptions of current during each revolution of the shaft, each of these interruptions
corresponds to a rupture of the current of the electro magnets
A longitudinal comb arranged parallel to the longitudinal axis of the commutator
communicates with all the rings except that whose insulating notch is under the
said comb.
The rings are placed so that the insulating notches are stepwise and the circuit
broken each time in that bobbin only which leaves the inducing electro magnet.
This arrangement is of capital importance as regards the motor.
The commutator is composed of metallic rings placed on other rings of hard india
rubber. The metal rings and the rings of india rubber are respectively separated
laterally from each other by thin hard india rubber washers. In each of the metal
rings is a hole in which is screwed or rivetted a metallic wire which at its other
end is connected with the wire of one of the induced bobbins.
The comb is a metallic plate the lower edge of which rests on the rings of the
commutator and which is connected by a wire with one of two rings which
surround the inducing bobbins and are insulated therefrom. The said comb is
affixed to a bracket screwed onto one of the bearings of the machine.
For generating machines the said comb may be composed of several insulated
plates connected sidewise to each other. For example for each of the metal rings
of the commutator a special plate might be arranged so that in the case of a machine
having eleven induced bobbins there would be eleven comb plates each of which
plates would be connected to its respective induced bobbin.
Several rings of the commutator might be grouped an for each group an
insulated comb plate arranged which would communicate with a respective group
of induced bobbins.
This arrangement is important for the division of the current.
The rings which surround the inducing bobbins are secured thereto by means of
angle rings of hard india rubber. One of the said rings receives the current coming
from the generating machine and communicates it by the bobbin wire to the twelve
inducing bobbins. This wire returns to the other of the said rings whence the
current is conducted to the commutator by a wire hereinbefore referred to. The
current is transmitted by the commutator to the different rings of the commutator
and is conveyed by the respective wires to the corresponding induced bobbins.
After having passed by these the wires return to the collector and this
communicates with the generating machine by means of a scraper connected to a
wire.
The commutator may be considered a means which will permit the application
of this motor for the recuperation of great forces ascending above a hundred horse
power for example; allowing that by means of its employment the object will be
gained of suppressing in a very great degree if not entirely the electric spark so
prejudicial to the useful result of motors actually operating in a derived circuit.
Lets us examine the effect of the machine in observing the working of the induced
bobbins. Whilst one of the induced bobbins which is on the point of rupture with
one of the inducing bobbins is passing to the next inducing bobbin and until the
said induced bobbin takes up a position with respect to the said next inducing
bobbin similar to that which it occupied with respect to the first mentioned
inducing bobbin (The time occupied by which action represents a complete
period) the shaft of the machine and all the induced bobbins have accomplished
a twelfth of a revolution and each of these, latter has caused a break of current
that is eleven breaks in all. There are therefore eleven breaks of current per

page_text: twelfth of a revolution or eleven times twelve which is one hundred and thirty
two breaks during one complete revolution.
If the number of induced bobbins were twelve there would only be twelve
breaks per revolution of the shaft but each of these breaks would produce an
effect much more injurious than the total of the corresponding eleven partial
breaks.
The fractioning of breaks is variable according to the variation in the number
of bobbins, if the number of induced bobbins differs from that of the inducing
ones the number of breaks per revolution is always equal to the two respective
numbers of bobbins
The commutator as hereinbefore stated at a given moment carries off the current
to an induced bobbin whilst the respective inductor. retains its current and may
still act přejudicially. To avoid this loss of power the collector hereinbefore
described may be replaced by a collector composed of twelve non-insulated rings
each of which is provided at its circumference with eleven equi distant notches.
The commutator scraper is composed of twelve metallic bands connected to and
insulated from each other. Each of these bands is in contact with the circum-
ference of its respective ring so long as one of the notches of this ring is not
under it.
I
The working of this arrangement is as follows. When one of the induced
bobbins is in rupture with one of the inducing bobbins one of the notches of one
of the rings of the commutator is.under one of the bands of the commutator scraper.
To make another break with the same inducing bobbin it is necessary that the next
induced bobbin should traverse one eleventh of a revolution, After this movement
the next notch of the ring will be under the same band of the commutator another
break will then occur and so on..
In order that the system may to well understood we will make a comparison
borrowed from hydraulics.
The electric spark produced at the commutator by the rupture of the current
is as injurious to the electric motor as would be the stroke of the rum in a
hydraulic motor with piston. Suppose a pipe full of water under pressure and
provided with a single outlet in suddenly closing this orifice there would evidently
be a ram stroke, but if this same quantity of water under this same pressure runs
off through eleven orifices and only one is opened and closed at a time the stroke
of the ram will not be produced. This is exactly what will be effected in electricity
by the employment of the commutator herein before describe as only one eleventh
of the total current will be interrupted at a time the electric spark if not altogether
nul will at least not be detrimental.
Another improvement consists in the novel construction of the induced bobbins
for generating machines. These bobbins are constructed with cores of iron wires
in view of the rapid demagnetisation of the core and of the rapid disengagement
of the solenoid's electricity.
The ends of the wires forming the cores of the said bobbins are inserted and
rivetted in holes formed in pieces of soft iron secured to and near the peripheries
of discs mounted on the rotatory shaft of the machine and to the said pieces of soft
iron the bobbin wires are connected
In this arrangement the commutator may be dispensed with or applied at
one or both sides of the machine.
In this latter case the construction of the commutator varies only in the sense
that all the insulated parts will become conductors and vice versa.