IMPROVEMENTS IN APPARATUS FOR GENERATING ELECTRIC CURRENTS." PROVISIONAL SPECIFICATION
Year: 1880

page_text: LETTERS PATENT to William Buller Fullerton Elphinstone, Baron Elphinstone,
of Carberry Tower, Musselburgh, North Britain, and Charles Wilson Vincent,
of Holloway, in the County of Middlesex, for an Invention of “ IMPROVEMENTS
IN APPARATUS FOR GENERATING ELECTRIC CURRENTS."
PROVISIONAL SPECIFICATION left by the said William Buller Fullerton
Elphinstone & Charles Wilson Vincent at the Office of the Commissioners of
Patents on the 13th July 1880.
WILLIAM BULLER FULLERTON ELPHINSTONE, Baron ELPHINSTONE, of Carberry
Tower, Musselburgh, North Britain, and CHARLES WILSON VINCENT, of Holloway,
in the County of Middlesex. "IMPROVEMENTS IN APPARATUS FOR GENERATING
ELECTRIC CURRENTS."
This Invention relates to improvements in the dynamo-electric machine for
which we obtained Letters Patent bearing date 27th January 1879, No. 332, the
object being to render the action of the machine comparatively steady and uniform,
and to enable it to produce, when desired, an alternating current. The first of these
results wo obtain in part by arranging the coils diagonally upon the armature
drum. This arrangement ensures that when the drum is rotating the coils will so
follow each other that one will enter the field before the immediately preceding
coil has left that field.
A further improvement tending to this end and providing also for the production
of an alternating curront is to cause a definite proportion of the induced current to
circulate through the electro-magnets. The importance of this principle of action
will be best understood when it is remembered that every alteration of the
magnetic force of the field magnets of dynamo-electric machines causes an alteration
in the amount of electricity produced in the coils of wire passing across the
magnetic field, and that in dynamo-electric machines the magnetic force of the
magnets is dependent on the amount of electricity induced in coils thus passing,
which is made to flow round the magnets. If the whole of the electricity evoked
is made to excite the magnets the magnetic force increases with the rapidity of
movement of the coils, but in dynamo machines other work has to be performed
besides that of exciting its own field magnets, and this work (notably where electric

page_text: lamps are in circuit with exciting coils and magnets) sometimes varies greatly in
amount in very short intervals of time. These variations re-act on both magnets
and coils, and cause great inequalities in the amount of electricity produced. For
example, if the lamp carbons throw in an increased resistance, less electricity passes
round the magnets; the field is proportionately weaker and the electricity is
lessened in amount, and its production may even cease altogether at the very
moment when more is required to produce a steady light.
The following are the ways in which we ensure circulation of a definite amount
of electricity in the coils of the field magnets:-
(1). The armature drum with its coils arranged in the direction above explained,
or in the manner described in the Specification above referred to is provided with
two layers of these coils.
One of these layers is connected-with the field magnets through a commutator.
The ends of the other layer of coils are likewise connected with a commutator,
which may be arranged so as to give either a continuous or an alternating current.
The relative size and length of the wires of the coils which connect with the
field magnets (which may be termed feeding coils) and of the working coils
depends on the size of the machino and the speed of rotation of the drum.
(2). The wires of the two (or it may be more) sets of coils may be laid side by
side, their ends being carried to separato commutators, as before described.
(3). The coils may be arranged in three or more layers, and connected either for
intensity or quantity; one or more sets being employed to feed the magnets, and
Que or more for the production of electricity to be used outside the machine.
(4): One-set of coils only may be used, the ends being connected up either for
quantity or intensity.
In this case the wire on the rotating drum will be so proportioned-in-diameter
and length to that on the field magnets that the latter wire cannot carry the whole
of the electricity which the revolving coil is capable of producing when the
maximum speed of rotation of the machine is reached. Thus, the drum coils will
act as if they were in two layers, the field inaguets being fed by a sort of shunted
current with which they are short circuited, while the remainder of the electricity
which the coil is capable of producing is available outside the machine so soon as
a conductor is attached capable of carrying that portion of the current induced in
the drum coils that cannot find an outlet through the field magnet coils. When
coils are thus arranged, one commutator and one set of brushes only are required.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Buller Fullerton Elphinstone & Charles Wilson Vincent in
the Great Seal Patent Office on the 13th January 1881.
WILLIAM BULLER FULLERTON ELPHINSTONE, Baron ELPHINSTONE, of Carberry
Tower, Musselburgh, North Britain, and CHARLES WILSON VINCENT, of Holloway,
in the County of Middlesex. "IMPROVEMENTS IN APPARATUS FOR GENERATING
ELECTRIC CURRENTS."
This Invention relates to improvements in the dynamo-electric_machine for
which we obtained Letters Patent bearing dato Twenty seventh January, Ono
thousand eight hundred and seventy nine, No. 332, the object being to render the
action of the machine comparatively steady and uniform, and to enable it to
produce, when desired, an alternating current.. The first of these results wo obtain
in part by arranging the coils diagonally upon the armature drum.
This arrangement ensures that, when the drum is rotating, the coils will so
follow each other that one will enter the field before the immediately preceding
coil has left that field. A further improvement tending to this end, and providing
also for the production of an alternating current is to cause a definite proportion of
the induced current to circulate through the electro-magnets. The importance of
this principle of action will be best understood when it is remembered that every
alteration of the magnetic force of the field magnets of dynamo-electric machines
causes an alteration in the amount of electricity produced in the coils of wire
passing across the magnetic field, and that in dynamo-electric machines the
magnetic force of the magnets is dependent on the amount of electricity induced in
coils thus passing, which is made to flow round the inagnets. If the whole of the
electricity evoked is made to excite the magnets, the magnetic force increases with
the rapidity of movement of the coils; but in dynamo machines, other work has to
be performed besides that of exciting their own field magnets, and this work
(notably where electric lamps are in circuit with exciting coils and magnets)
sometimes varies greatly in amount in very short intervals of time.
variations react on both magnets and coils, and cause great inequalities in the
amount of electricity produced. For example, when the lamp carbons offer an
increased resistance a proportionately diminished amount of electricity will pass
round the magnets and the field will be proportionately weakened. The conse-
quence of this will be a diminished production of electricity, and that at the very
moment when more is required to maintain the brilliancy of the light.
These
The following are the ways in which we ensure the circulation of a definite
amount of electricity in the coils of the field magnets.
(1). The armature drum, with its coils arranged diagonally, as above explained,
or in the manner described in the Specification above referred to, is provided with
two layers of these coils.
One of these layers is connected with the field magnets through a commutator.
The ends of the other layer of coils are likewise connected with a commutator,
which may be arranged so as to give either a continuous or an alternating
current.
The relative size and length of the wires of the coils which connect with tho
field magnets (which may be termed feeding coils), and of the working coils will
depend on the size of the machine and the speed of rotation of the drum.
(2). The wires of the two (or it may be more) sets of coils may be laid side by
side, their ends being carried to separate commutators as before described.
(3). The coils may be arranged in three or more layers and connected either for .

page_text: intensity or quantity, one or more sets being employed to feed the magnets, and
one or more for the production of electricity to be used outside the-machine.
(4). One set of coils only may be used, the ends being connected up either for
quantity or intensity. In this case, the wire on the rotating drum will be so
proportioned in diameter and length to that on the field magnets that the latter
wire cannot carry the whole of the electricity which the revolving coil is capable
of producing when the maximum speed of rotation of the machine is reached.
Thus the drum coils will act as if they were in two layers, the coils of the field
magnets taking only their due proportion of the induced current.
In the accompanying Drawings we have shewn in several views a dynamo-
electric machine constructed according to our Invention. Fig. 1 is a longitudinal
central section of the machine; Fig. 2 is a transverse section of the same taken in
the line 1, 2, of Fig. 1, and Fig. 3 is an elevation of the commutator end of the
machine, the collecting brushes being omitted. A, A, are standards bolted to the
bed plate B and carrying a fixed shaft C.
To this shaft are fitted radial platos of soft iron D, D, constituting a stationary
internal magnet.
Mounted loosely upon the shaft C, and surrounding the magnet D, is a drum E,
constituting an armature. The heads of this drum consist of open discs cast with
elongated hubs or sleeves and fitting onto coned shoulders on the shaft C. The
heads are connected to the barrel of the drum by screws inserted in its periphery
or in any other convenient manner. Surrounding the drum are hanks of insulated
wire laid diagonally, and so as to cover the periphery of the drum. The way of
arranging these hanks and of turning down the terminals of the hanks to the
cominutator is clearly-shewn in Figs. 4 and 5; Fig. 4 being a side view of the
armature drum, and Fig. 5 an end view thereof.
This armature drum is situate between the side frames F, F, which are bolted to
the bed plate B, and are secured together by transverse tie roda The use of these
side frames is to carry the magnets G which surround the armature drum and
constitute the outside field magnets. These magnets G are composed of plates of
soft iron having a V-shape in cross section, which shape facilitates the winding-on
of the insulated wire. The magnets G are set radially and concentrically around
the armature drum, and are secured to the side frames by transverse bars of
wood G¹ which extend from one side frame to the other.
H is the commutator keyed on a sleeve of the armature drum, and I is a band
pulley cast with the other sleeve of the drum. Through this pulley rotary motion
is imparted to the armature drum for the purpose of setting the machine in action;
K is an annular frame supported by pillars K¹ which stand up from the bed
plate. This frame is arranged concentric with the armature drum, and is formed
with a rebate at its inner side to receive a ring L correspondingly rebated, which
carries the commutator brush holders.
By referring to the sectional view, Fig. 2, it will be seen that the magnet D is
formed with six leaves. Upon these leaves the insulated wire is so coiled as to
constitute them alternately north and south poles, as indicated by the letters N. S.
Similarly the magnets G are so arranged as to present opposing poles to the several 4
poles of the magnets D, as also indicated by the letters N. S.
Both the internal and external magnets are provided with broad pole pieces for
the purpose of presenting broad magnetic fields to the coils or hanks of the rotating
armature, and the coils of these two sets of magnets are connected together, and to
their collecting brushes, by wires in any convenient manner. The inclination of 5
the hanks of the armature with respect to the axis of the drum may vary without
material detriment to the object in viow so long as the hanks in their revolution
follow each other in such manner that a fresh hank will enter the field before tho
immediately preceding one has left that field.
An obvious modification of the means for obtaining a uniform current is to 5
arrange the magnets diagonally as respects the axis of motion of the armature, tho

page_text: hanks being set around the armature drum parallel to its axis of motion, as
horetofore. In this case, the hanks in their revolution will follow each other, so
that two or more will pass together through the same magnetic field, entering it
and leaving it at different times. Fig. 2 sliews that the drum is furnished with
eighteen hanks. These hanks may be composed each of two wires, so as to
produce two distinct currents, or the number of hanks may be doubled and formed
of single wires. Thus the banks will, in either case, present a total of seventy-two
terminals, which are severally in permanent communication with an insulated
blado of the commutator H. The construction of this commutator is best illustrated
by the detached views, Figs. 6 and 7, which represent it in full, size and in its
proper position with relation to the collecting brush ring.
It consists of a cylinder of vulcanite grooved longitudinally to receive two
sets of brass flanged plates h³, h², the flanges of the plates ¹ being double the length
of the flanges of the plates h³.
These flanged plates are shewn detached, in plan and side views, at Figs. 8 and 9.
These plates, it will be understood, are all of the same length to admit of their
being held in place by binding hoops ³, which are common to all. As the banks
on the armature drum present a total of seventy-two terminals, the commutator is
furnished with a corresponding number of plates h³, h³, for taking off the currents
and presenting them to the collecting brushes.
These brushes are fitted in brush holders which are carried by a ring L which is
capable of receiving an axial motion on its annular frame K for the purpose of
bringing up any one or more of the brushes within easy access of the attendant to
permit of their adjustment or removal without stopping the action of the machine.
The brush holders M, M', are divided into two sets and mounted on opposite
sides of the ring L, care being taken that they are properly insulated therefrom.
The brushes of the holders A bear upon the blades and take off the currents for
the working or outside circuit, and the brushes of the holders M¹ bear upon the
blades h of the commutator and receive the current for the short circuit around
the field magnets D and G. The number of these latter brushes will be limited by
the receiving capacity of the wire of the magnet coils, and through their aid a
plenum of electricity will be caused to circulate around the field magnets, and that
without any variation, whatever may be the variations in the resistance in the
outside circuit. The brushes M on the outside of the ring L collect the currents
for the outer circuit, and these currents may be obtained either as quantity currents,
intensity currents, or alternating currents, according to the method adopted of
coupling up the wires from these brushes.
As a simplification of the above described machine we employ a wire of a
conductive capacity equal to the two wires already referred to for composing the
coils or hanks for the armature drum. In such case the commutator will bo a
single one, in contradistinction to the double commutator shewn in the Drawing,
that is to say, the terminals for eighteen hanks being only thirty six in number
will require only a corresponding number of blades for transferring the electric
currents to the collecting brushes. Theso brushes will constitute one set only, and
will all be in connectiou with the main circuit.
From this circuit the electricity for exciting the electro magnets will be taken
by a shunt circuit to the electro-magnet coils, and thus a plenum of electricity will
be maintained therein, as already explained.
Having now set forth the nature of our Invention of " Improvements in
Apparatus for Generating Electricity," 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 claim,-
..
First. The arrangement above described for setting the armature coils or hanks
with a lead relatively to the field magnets, so that the leading end of each coil or
hank, or that end which first enters the field, will on the rotation of the drum enter
the magnetic field before the rear end of the preceding hank has left it.
'

page_text: Second. The means above described for supplying to and maintaining in the
coils of the field magnets a plenum of electricity for the purpose of maintaining the
efficiency of the machine.
In 'witness whereof, I, the said Charles Wilson Vincent, have hereunto set my
hand and seal, the Twelfth day of January, in the year of our Lord One 5
thousand eight hundred and eighty one.