IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
Year: 1882

page_text: LETTERS PATENT to Denis Alexandre Chertemps and Louis Dandeu, both
of Paris in the Republic of France for an invention of "IMPROVEMENTS IN
DYNAMO-ELECTRIC MACHINES."
PROVISIONAL SPECIFICATION left by the said Denis Alexandre Chertemps
& Louis Dandeu at the Office of the Commissioners of Patents on the
12th April 1882.
DENIS ALEXANDRE CHERTEMPS and LOUIS DANDEU both of Paris in the
Republic of France "IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES."
Our Invention consists in a self exciting dynamo electric machine in which we
have endeavoured to destroy the antagonistic effects of contrary currents which
exist in all other machines, causing irregularities in the currents produced.
The machine is composed of two circular plates of cast iron upon which are
mounted a series of electro-magnets secured by strong bolts.
These two plates are keyed upon an axle, and constitute the induction system,
or magnetic field, rotating on opposite sides of an insulating support of wood
furnished with a ring of electro magnets constituting a fixed armature. The axlo
which carries the rotating field is mounted in blocks bolted to the base of the
machine.
Upon the axle, and between one of the field plates and the adjacent plummer
block, is placed a commutator, the plates of which are formed so as to interlock
and afford a smooth surface for the brushes or rubbers to bear against.
Upon the adjacent plummer block are formed segmental slotted wings for
carrying the rubbers or brushes, which can thus be easily adjusted to the position
it is desirable they should occupy.
The current from one or more of the electro magnets of the fixed armature is
used for the purpose of feeding the rotating field magnets, the currents from the
other electro magnets being used to feed the lamps or other apparatus connected
with the machine.

page_text: Upon the central fixed armature is arranged a second commutator or grouping
table composed of a series of pieces of copper corresponding to the number of
terminals of the armaturo wires, to provido for the separation or grouping of the
circuits as may be found desirable.
Upon the commutator, which is provided with a grouping slide are arranged a
number of small electro-magnets (one for each circuit), the wires of which are
taken from the several armature circuits. The purpose of these electro magnets is
to instantly re-establish the communication on the rupture of any of the circuits,
accidental or otherwise.
These electro magnets are composed of two small bobbins wound with wire
proceeding from the fixed armature, and they are provided with an armature,
which armature has for its object the nutomatic re-establishment of a broken
circuit.
When the circuit is broken the armature will be attracted and close the circuit
aliew.
The electro magnet of the fixed armature, which serves to excite the electro
magnets of the field, is put in communication with these latter by two conducting
wites, which connect with two rubbers or brushes bearing upon the commutator
which transmits the current by two conductors into the electro magnets of the
field, in order to excite them in a permanent and proportional manner, without
having recounse to any of the metallic parts of the machine.
We have discovered that there was an advantage in making these dispositions
in view of the disastrous relations which exist in all metallic mountings of what-
ever kind.
It may be remarked that all the dangerous parts have been withdrawn with
care, and that by these arrangements there will be neither antagonistic nor reversed
currents created, and all the current produced will be entirely utilized.
By the use of this arrangement of apparatus experiment has shewn that when a
certain number of lamps is put in circuit, and they are extinguished one by one,
the remaining lights will shew no variation in brilliancy, their luminous intensity
being neither augmented nor diminished, but as each lamp is thrown out of circuit
the motive force employed diminishes proportionately, and the contrary phenomen
is produced as the lamps are reinstated, that is, the motive force required will
proportionately incronse."

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Denis Alexandre Chertemps & Louis Dandeu in the Great Seal
Patent Office on the 11th October 1882.
DENIS ALEXANDRE CHERTEMPS and LOUIS DANDEU both of Paris in the
Republic of France "IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES"
Our Invention relates to a self-exciting dynamo electric machine in which the
antagonistic effects of contrary currents causing irregularities in the currents
produced are destroyed, and a better result is obtained than it has been heretofore
possible to secure by machines of like size and with expenditure of an equal
amount of motive force.
In Sheet I of the accompanying Drawings fig 1 shews our improved self-
exciting dynamo electrical machine in front clevation, and Fig: 2 is a plan view
of the same-In sheet II fig 3 is a transverse vertical section taken in the line 1, 2
of Figures 1 and 2 and Fig: 4 is an elevation of the commutator end of the
machine.
In these figures A is a horizontal shaft mounted in plummer blocks B B¹ secured
to a base B². This shaft carries a pair of cast iron discs C. C¹
Fitted to the inner face of each of these discs is a set of hollow electro magnets
D. D' arranged in a circle concentric with those discs, and forming together the
rotary fields of the machine-These hollow electro magnets which are made fast to
their discs by bolts or nuts we make by preference in the manner shown at Fig 4b
(hereafter described) because they facilitate the magnetization and at the same
time tho weight of the rotating fields is reduced and consequently the power
required to drive the machine is lessoned.
Between these rotary fields is situate a stationary armature composed of a block
or plate E of wood or other non-conducting material and pierced through with a
ring of holes the axis of which ring corresponds with the axis of the field magnets.
The diameter also of the ring of holes is such as to ensure their standing opposite
the field magnets as those magnets are rotated.
The ring of holes in the block E we fit with bobbins F which project out from
opposite sides of the block of insulating material. The coils of these bobbins are
preferably wound upon a core of iron composed of several tubes fitting the one
within the other as shewn in the sectional view Fig: 4b the object being to allow
of access of air to the interior and thereby to avoid the heating of the bobbins and
also to reduce the weight of metal employed to a minimum. The inner or filling
tubes may be coated with paper to insulate them from each other before driving
them into place.
These hollow bobbins we so adjust with respect to the field magnets that tho
latter shall just clear them when rotating. The drawing shews the fixed armaturo
as formed with six of such bobbins, the wires of which are conducted up to pairs of
metal blocks e e' mounted on a block E* fitted preferably on the insulating
armature block E. This block is built up in pieces as shewn at Fig 3, to avoid
the effects of warping and the parts are bound firmly together and to the bobbins
by means of a netal strap which passes over the compound block and holds it
down firmly to the bed plate; or the armature block may be formed as shewn in
side view and in cross section at figures 4 and 4b Sheet II.-Made fast by means
of binding screws e² to the metal blocks e e¹ are pairs of wires, one of which leads
off to a pair of brushes or rubbers G, and the remainder to say the lamps, or to
the work that is required to be performed.
The rubbers G are mounted adjustably on the plummer block B¹ and are

page_text: 21
intended to supply a current led off from what may be termed the "exciting
lobbin to a emulator H in connection with the whole of the field magnets.
The commutator which is mounted on the shinft A receives alternating currents
from the exciting bobbin of the armature, and these currents it is designed to
rectify and transmit as a continuous current to the field magnets.
For this purpose we construct the commutator in a peculiar manner which
ensures that in its rotation one section of the commutator shall not leave the
rubber or brush until the next adjacent section is in contact with the samo rubber
or brush.
Figures 5 and 6 Sheet 11 shew the commutator detached from the machine
Fig 5 being an end view and Fig: a side view representing the two parts of
which the commutator is composed, separated.
The commutator H may be described as composed of two hollow cylinders
each with a closed end their peripheries being so cut away as to permit of their
interlocking to the full length of the cylinders
The number of inter-locking parts of the commutator depends upon the
number of electro-magnets contained in the field, and the number of bobbins in
the armature. We have said that the number of bobbins shown in the drawing of
the armaturo is six and there are also six pairs of electro magnets in the rotating
field
This necessitates the use of a corresponding number of interlocking parts in the
commutator, vis: threo for each cylindrical counterpart of the commutator. These
interlocking parts marked hand h' respectively are tapered in steps as shown in
the drawing and when fitted together as nt Fig: 2 upon the shaft A and insulated
therefrom and from each other together form a hollow cylinder with a smooth
periphery, upon the opposite sides of which the rubbers G bear. One portion of
this commutator is connected with one terminal of the field, and the other portion
is connected with the other terminal thus when the machine is in action a current
of electricity is passed from the armature through the rubbers G and commutator H
to the field magnets.
As however the commutator presents practically but two surfaces to the rubbers
and these in succession, continuous electric currents will be transmitted to the field.
By adjusting the commutator relatively to the field magnets and thereby ensuring
the shifting of the rubbers from the middle step of one segment to the middle step
of the next adjacent segment at the moment that the field magnets are passing the
spaces between the armature bobbins and consequently through neutral points all
liability to "sparking" will be removed.
In order to provide exciting currents for the field magnets proportionate to the
requirements of the bobbins from which the currents are to be taken for illu-
minating or other purposes, we coil the exciting bobbin which is connected with
the brushes or rubbers G with wire of a gauge corresponding to the gauge of the
wire on the field magnets, and the weight of this coil wo make to correspond with
the weight of the other bobbin coils of the armature. The conducting wires through
which the exciting currents are passed to the field magnets will also be made of
equal gauge, by this means induced currents will be passed into the field in the
exact proportion required to give full full efficiency to the field magnets.
We have said that the wires of the armature bobbins are led up to the pairs
of blocks e e' These blocks are fitted with clamping screws for connecting thereto
the wires of the different circuits. In order however to combine together two or
more currents of the working circuits according to the work in hand we provide
a forked sliding piece K Fig 4c which is made to under-run binding screws fitted
to the several blocks and thereby to couple them up as required, or the plates may
be connected together by hooked attachments
To provide for closing a lamp circuit when broken by accident and thereby to
Avoid the beating of the metal coro of the armaturo bobbin and the consequent
injury to the coil thereon, we place within cach lamp circuit a small electro magnet
mounting the same on the fixed armature as illustrated at Figures 7 and 8 in front

page_text: and side elevations-These electro-magnets I are carried by bracket pieces screwed
to the block E and they overlie a plate K' which is attached to a lever hinged to
the block E* This plate K' overlies a pair of terminal blocks e c¹ and is intended
by contact therewith to short circuit the currents generated in the bobbin connected
therewith. When the machine is set in action the currents passing to one of the
terminal blocks will be divided, a portion passing to the opposite terminal by the
plate K, and the other portion passing around the electro magnet I, and so on
to the lamp and back to the terminal e The electro magnet being by this means
excited will lift the plate K' and retain it in its raised position so long as the
circuit remains unbroken So soon, however, as the breaking of the circuit takes
place whether by accident or otherwise the plate K¹ will fall and close the circuit
cutting out the broken portion.
Having now set forth the nature of our Invention of "Improvements in Dynaino
electric machines" and explained the manner of carrying the same into effect
we wish it to be understood that under the above in part recited Letters Patent
we do not claim generally exciting the field of a dynamo electric machine by
currents derived from its armature whether stationary or rotating but what we
claim is.
First In a machine containing a fixed armature with rotating field magnets
arranged in pairs on either side thereof and provided with a commutator the means
above described for supplying to the field magnets exciting currents proportionate
to the capacity of the armature bobbins to receive induced currents.
Second. In a machine containing a fixed armature with rotating field magnets
arranged in pairs on either side thereof the use of an interlocking commutator
constructed as described for rectifying reversed induced currents and delivering
such rectified currents to the field magnets without breaking contact with the
rubbers.
Third The sliding forked piece K for combining together as required two or
more of the metallic blocks e e' from which the induced currents are taken sub-
stantially as set forth.
Fourth-The short circuit closing apparatus in connection with the terminals as
and for the purpose above described with reference to Figures 7 and 8
In witness whereof I the said Louis Dandeu have hereunto set my hand
and seal the Twenty-eighth day of September One thousand eight hundred
and eighty two:
LOUIS DANDEU. (L.S.)