Improvements in Dynamo Electric Machines.
Year: 1895

page_text: Date of Application, 22nd Oct., 1895-Accepted, 7th Dec., 1995
COMPLETE SPECIFICATION.
Improvements in Dynamo Electric Machines.
I, JAMES DEVONSHIRE, Secretary of the British Thomson Houston Limited
of 38 Parliament Street, Westminster, London (a communication from abroad by
Elihu Thomson, Professor, of Swampscott in the State of Massachusetts United
States of America) do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertamed
in and by the following statement
The present invention relates to dynamo-electic machines, and has for its
object to provide a machine of the multipolar type directly connected for a number
or series of nic light circuits, in which may be maintained the simplicity of
commutation and possibility of regulation for each of the separate circuits, as it
exists in the ordinary are lighting machines. The object of the machine is
primarily to allow of duect driving for are lights; it is the efore made a multi-
cncuit machine, in each of the uncuts of which a series of are lights may be run
with continuous cients if desned Briefly, the machine consists of a revolving
set of field-magnets on a water wheel or steam engine shaft, the field-maguets being
multipolar, and the number of poles being chosen with respect to the speed and
rate of cutting of the lines desired. The armature is stationary and is provided
with circuits HoD-overlapping, constituting groups of three coils or three phase
windings, from which three terminals are canied out This winding is supported
on a laminated structure, divided into sections, so that any section may be removed
with its winding for repairs without disturbing the integrity of the rest of the
structure, which may even be run with one or more sections reinoved
In order to commute the currents, commutators are driven synchronously with
the machine, or at higher rates. This can be done by synchronous motors diven
by the machine causing the commutators, and led by one of the three phase
circuits of the machine, or it can be done by direct gearing, which is the arrange-
ment shown in the figures. The machine shaft carries a laige gear which engages
with small pinions on each of the commutator shafts, the commutators being
revolved at a speed relatively greater than that of the main machine in the
proportion of half the number of poles in the main machine, that is, the com-
mutato is virtually bi-pola, 01, if the commutator has four poles, its speed would.
be one-half as great
It the field poles of the main machine are twelve in number,
the commutator would revolve six times as fast (if bi-polai) as the machine. The
construction admits also of the use of the open coil aangement of generating coils
and of commutators such as are common on are machines and which have certam
advantages, particularly with respect to simplicity Each of the commutators
carries three ings lot connection by brushes to the stationary aimature windings,
and caries also a three segment commutator with the ordinary ariangements of
brushes, either controlled or not by a regulator. Of course the style of com-
mutator and connections of ccils might be changed to any other, such as that used
on the brush machine, but this would require a variation of the winding The
arrangement 18 such that any commutator may be thrown out of action, or even
removed, without stopping the machine, and devices can be inserted between the
armature windings and the commutator to modily the currents in
case those

page_text: currents do not have the requisite character for the operation of are lights, thus,
the currents of the machine may be made, by the armature reaction, csistances,
&c, to be of the nature of those supplied by air lighting machines, tending to a
fall of potential on an increase of current, and thereby giving stability to the
current on the circuit or particular devices, such as reactive coils, constant current
transformers, &c, may be inserted between the connections from the stationniy
windings and the commutating devices, and a transformation of potential up or
down may
he at the same time accomplished if transformers are employed. While
the machine is thus primarily adapted to work a number of circuits of mic lights, it
may be on occasion employed to operate three-phase motors or three-phase lighting
encuits, or may be used in various transformer combinations to operate two-phase
or other polyphase systems.
The accompanying drawings show an embodiment of the present invention,
Fig. 1 being a side elevation, partly in section.
Fig. 2 a plan of a machine embodying the invention,
Figs 3 and 4 details of the commutating and regulating arrangements, and
Fig. 5 a diagram of the cunts as it is contemplated applying the machine.
In Fig. 1, B, B is the base of a machine in which the shalt is vertical, as is
most convenient when water power is used X is the shaft which carries the
evolving field-magnet structure F in the shape of a wheel with projecting poles,
the coils being marked C, C, &c. They are twelve in number, shown in Fig. 2
The poles of these held-magnets revolve neat to a laminated armature structure A
made of sheet non with projections, pictciably extending inward; and this
structure, which is divided into sections, is sustained by vertical iods or bolts, as
at R, R, three rods or bolts being shown to each section The construction is such
that by running back the nuts. as at n, n and n', n', cucular washers may be
separated from each other and allow the sections to slide out with the bolts,
through the slots, s, 2, 3, &c, Fig 2, while when the nuts n', n' are tightened up,
the washers under the nuts fall into counterbored holes and secure the whole
stincture fumly, so that there can be no sliding outward This, of course, is a
mino matter of construction which could be modified in various ways. The
particular amature section in Fig 2 which is indicated as removable, has been
shown with the upper ring on fraine cut away, exposing the joint between two
sections, as at JJ. The coils are wound as a non-overlapping system, the
separate portions of each section of which, however, do overlap Mounted on the
shaft of the machine is a gem wheel G, in this case shown as a bevel gear,
engaging with pimous P, a number of which may be used, corresponding to the
number of encunts on the mature These pinions dive small accessory shalts,
shown separately in Figs 3 and 4, which catly collector mngs and commutators,
all suitably insulated, of course, each ring being connected to a segment of
the commutator. The brushes beating on the ungs are indicated at b. b₁, b²,
and the commutator at K. Suitable standards support the shaft, and devices foi
adjusting and securing the parts in place are indicated at Y, and are carried on the
fame of the machine The brushes L, L, on the commutator, Fig. 3, may be
mounted as usual for adjustment, and may be provided with brush shifting
arrangements such as are common in are lighting machines for regulating the
current, on adjusting the bushes to the proper non-sparking positions Cutient
15 fed into the field-magnet system from any suitable source by the usual method
of connerting the terminals of the coils to insulated rings on the shalt, shown only
in Fig. 5, with brushes bening on the rings
Fig 2 shows fom of the commutating devices in place, but does not show the
connections Fig 1 shows two of the commutating devices without connections
In Fig. 5 a comprehensive view of the connections of the whole machine is
given, it being understood that the connections are subject to modifcation. The
windings on the aimature, while shown as what are now known as
"delta" or
closed cucuit windings might be modified to be of the open coil type, or "Y"
windings, if other than the three coil winding on three-phase winding be employed,

page_text: the connections and arrangements would be modified accordingly. The field-
magnet coils are indicated at C, C, C, &c. and central rings N, N' are shown
These
with brushes bearing thereon for carrying curent into the field coils
brushes are included in one of the circuits of aic lamps, as at 1, l, with the com-
mutator K, for rectifying the curients This commutator has its connections
direct to the windings in which the current is gene ated by the revolution of the
field, but this could only be done when the "characteristic" of the machine was
proper for the operation of an aic lighting cucmit It is to be understood,
however, that the series of lights 1, 1, might be a series of incandescent lights, or
other resistances, in which case the dynamo need not be specially adapted to are
highting. Where, however, the characteristic is proper for aic lighting, this
airangement of circuit might be repeated in the machine shown, six times, and six
en cuts of are lights he operated independently of each other, and the regulation
of curent needed when lights were extinguished or stated to operation be
accomplished by a regulation of the brushes around the commutators in the known
ways, cach cucuit taking care of its own regulation
As indicating other connections which might be employed with the machine,
either for all the encunts or for any particular one or more of them, there is
indicated a set of lights, 2-2, which may be are lamps when the characteristic of
the machine is proper, or incandescent lights in series where it is not adapted to arc
lights. the curent being driven though a cominutator, K³, and being transformed
up from the armature winding by a triplicate transformer T, the primary coils of
which may be of low potential from the amature winding A, while the secondaries
lause such current to high potential and are insulated entirely from the armature
winding, the currents from the said secondaries being cominated to continuous
currents for the line by the commutator K. At 3, 3, a encuit is shown which may
contain are lights or other resistances In case the dynamo characteristic is such
as not to effectively operate are lights, the current may pass through a set of
transformers Twinch are constructed to give a proper characteristie to the current,
that is, the transformers may be "leakage" transformers, the tendency of the
secondary cents of which, even where the primary carents air fel by constant
potential from the machine, is to become of constant value so that they may be
called constant current tranformers, or transformers having a constant curent
tendency. The secondary coils are connected as in th.ce phase system, and the
tominals carried to the rings which take the cuitents to the commutator segments
of the commutating device K, and the primary connections of cucuits are in the
manner carried to the thire phase connectioUS Where the machine charateristic
is not quite right for the operation of the cucunt, or where it is desirable to modity
the wave of current sent to the cucuit, either in its form or electro-motive force,
there may he interposed a set of reactive coils I, II, between the armature coil
system A and the commuting device K', and by making the reactive cods 1, I, I,
adjustable in any way, the desired action or reaction upon the circuit may be secured.
The armature winding A³ might be connected to run through a cominutator, if
desued, or the commutator may be removed and the connections made duectly to
the transformers T³, or the connections may be made without transformation to the
system of lights on motors, such as a three phase moto M taking caurent from the
winding A The regulation of the potential for the running at the motor line may
be secured by changing the relations of the tunas in the primary and secondary of
the transformet itsell, o in other ways Again, a lighting cncuit, without
commutation, may be operated from any one or more of the windings, as A, where
through transformation, as by a set of transformers T', incandescent lamps connected
in parallel are supplied with a current of proper potential to operate them, the
circuit being indicated at V. In this case the iegulation for potential may he made
by the well known means of changing the relatious of the turns in the transformers,
o in other ways If such a machine as has been descubel be running with a
number of its circuits supplying are lamps or are lamp en cuts, or series (ncunts,
with proper resistances, and the regulating devices to the current are employed in

page_text: connection with the commutation, while other of its cucuits are connected for
motor or incandescent lamp work, in parallel, then the regulation of the field
strength or curient in the coils of the field-magnets C, C, C, may be made to keep
the potential of the lighting encuits constant, while not greatly aflecting the
operation of the series circu.ts, provided the regulation is within a certain range.
It would be within the invention as contemplated to couple the coils ou the
armature, wheu dong constant potential work, in multiple, so as to diminish the
armature reactance, or to run with a lessened current density in the winding, while
for ale work or constant current work in series, the coils would be coupled for the
higher armature reaction, or run with a much higher density of current in the
winding.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be perfouned as communicated
to me from abroad I declare that what I claun 18
1. A dynamo-electric machine having a stationary armature provided with
independent windings overlapping in sets, the sets not overlapping each other, and
separate encuits extending from each independent winding
2 A dy onmo-electric machine having a stationary external amature provided
with sets of independent overlapping windings aanged in different positions
around its periphery, the sets of windings not overlapping each other, and separate
circuits extending from each independent winding.
3. A dynamo-electric machine having a stationary external amature divided
into sections, each section provided with an independent winding overlapping upon
itself, but not overlapping any other section, separate circuits extending from the
different windings, an internal revolving field-magnet, and a connection between the
field magnet windings and one of the independent en cuts melading a commutator.
4 A dynamo-electric machine having a stationary armature provided with
independent sets of overlapping windings occupying differem relative positions
around its periphery, the sets of windings not overlapping each other, separate
commulators conuected to some of the windings, and means for driving the several
commutator synchronously with the evolution of the machine
5. A dynamo-electric machine having a stationaiv external amature composed of
independently removable sections, each section carrying an independent overlapping
winding not connected to any other section.
6. A dynamo-electic machine having a stationary external amature composed
of separately removable sections, each section having an independent winding not
overlapping any other section, and commutators driven synchronously with the
machine and connected to the several windings.
7. A dynamo-electric machine having a stationary external amature composed
of independently removable sections, each section provided with an independent
winding not overlapping with any other section, synchronous commutators for some
of the sections, separate circuits for each section, and transformers connected to the
other sections supplying some of the encuits, the other encuits being supplied with
continuous eurent from the commutators.
8 A dynamo-electie machine having a stationary external armature provided
with independent three phase windings, the windings overlapping in sets, but the
sets not overlapping each other, and separate chcuits extending hom cach
independent winding.
9 A dynamo-electric machine having a stationary external amature provided
with independent three-phase windings overlapping in sets, the sets not overlapping,
separate circuits extending from each independent winding, and collecting devices
in the separate cu cunts, some of such collecting devices consisting of synchronous
comtnutators.
10. A dynamo-electric machine having a stationary external amature, constructed
with independently removable sections, each section carving a three phase winding,
the winding of the separate sections not overlapping, separate cucuits extending

page_text: from each independent winding, some of the circuits provided with synchronous
commutators, an internal revolving field-magnet, and connections between one of
the circuits carrying commuted currents and the field magnet
Dated this 22nd day of October 1895
For the Applicant,
J. C. CHAPMAN,
70, Chancory Lane, London, W.C, Chartered Patent Agent..