IMPROVEMENTS IN DYNAMO OR MAGNETO-ELECTRIC MACHINES
Year: 1882

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for an Invention of
IMPROVEMENTS IN DYNAMO OR MAGNETO-ELECTRIC MACHINES."
A com
"
munication from abroad by James John Wood, of Brooklyn, New York,
United States of America.
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents on the 27th May 1882.
WILLIAM ROBERT LAKE of the Firm of Haseltine, Lake, & Co., Patent Agents.
Southampton Buildings, London. "IMPROVEMENTS IN DYNAMO OR MAGNETO.
ELECTRIC MACHINES." A communication from abroad by James John Wood,.
of Brooklyn, New York, United States of America.
My improvements are more especially applicable to the "Gramme" type of gene-
rator or other dynamo or magneto electric machine in which the coils or sections of
the armature are connected in what is known as a "closed circuit" and the said
Invention consists essentially in an improved form of current regulator whereby'
the force of the current produced by the machine may be increased or decreased
as may be required to suit the kind or amount of work which is to be performed
by the machine.; for instance in electric lighting the current may be reduced to
suit one lamp or increased to suit any additional number of lights up to the
maximum number capable of being maintained by the machine.
To this end the main feature of my Invention may be stated to consist in the
combination with a Gramme or equivalent form of armature and a movable brush
holder adapted to move the brushes on the commutator to the point of greatest:
effect towards the minimum position of a manipulating or adjusting device engaged
with the brush holder and with a catch or lock and provided with fixed definite
points of graduation and engagement whereby the brushes can be set and held at
certain indicated and fixed positions corresponding to distinct changes of current
suited for one or more lights without trouble or calculation on the part of the
;

page_text: operator. My Invention also consists of the special construction of the parts as
hereinafter fully set forth.
In the accompanying Drawing,
Figure 1 represents a side elevation partly in section of my improved form of a
Gramme dynamo electric generator provided with my improved current regulator.
Figure 2 is a transverse section of the said generator on the line x x Figure 1,
looking to the left.
Figure 3 represents an end view of the hand-wheel of the current regulator
shewing the fixed definite graduations and points of engagement corresponding to
current changes suited to any number of lights from one to ten.
Figure 4 is a fragmentary detailed view, drawn to an enlarged scale, illustrating
the catch for holding the hand wheel or manipulating device of the regulator at
the desired adjustments or graduations.
In Figures 1 and 2 a a indicate the side frames or sustaining standards of the
machine which are joined at the top and bottom by the wrought iron webs or
plates b b that form the cores of the field magnets cc; d d are the pole pieces of
the said field magnets which project from the middle of the cores b b as usual and
are of nearly semi circular shape so as to encircle nearly one half of the armature,
the separated, but approaching ends of the pole pieces being joined by brass plates e
in the ordinary manner; f is the armature which revolves in the usual manner
between the encircling poles and is mounted on the shaft k; this shaft is journalled
in the standards a and is provided with the commutator g, with which the coils of.
the armature are connected in the same manner as those of Gramme armatures
or closed circuit armatures. hh indicate the collecting and transmitting brushes
which bear upon the commutator in the usual manner, and project from a movable
arm or yoke i mounted upon the bearing at the commutator end of the armature
shaft and capable of radial adjustment thereon as usual. The manner of and means
for the adjustment of this yoke or brush-holder is in this case is however novel
and constitutes part of the present Invention.
I have not shewn or described the manner of constructing the armature or of
connecting the coils or sections thereof with the sections of the commutator this
being as before stated on the Gramnie or close circuit principle which is well known
to experts and electricians and in itself forms no part of my present Invention;
and therefore requires no further description herein. I would call attention however
to the well known fact that in this class of armatures that revolve between the
opposite poles the currents always flow in a constant direction in each half of the
armature the currents from the several coils all tending to flow from one diametrical
point in the armature around each half to the opposite diametrical point so that if
the brushes bear upon the commutator at these diametrical points, they will convey
the full maximum current of the machine. These maximum points will be at
opposite ends of a diametrical line passing through the armature between the
opposite poles of the magnet and coincident with the diagonally opposite corners
of the opposite pole pieces. Hence if the brushes rest upon the commutator so
as to tap the armature at this position as shewn in Figure 2 they will convey the
full effective current of the armature as before stated but if the said brushes be
moved to a different radial position from this the force of the current conveyed by
the brushes will be reduced by reason of a partial mutual counteraction of the
currents from each half of the armature, and this reduction will continue as the
brushes approach a position at right angles to the aforesaid maximum position
where the effect will be due to the complete counteraction of the two currents in
the armature at this point. In practice the current will become inappreciable some
time before the brushes reach the theoretically minimum position, but the effective
range through which the brushes may be moved will vary in different machines
according to individual peculiarities. Thus in some machines in which the field of
magnetic force is concentrated abruptly near the ends or corners of the pole pieces,
the range will be less while in other machines in which the magnetic force is more
diffused along the pole pieces the range will be greater.

page_text: Now according to my improvements, in adjusting the brushes and regulating the
current of the machine I provide the brush holder or yoke i with a toothed
segment as clearly shewn in Figure 2. Into this segment gears a pinion fixed on
the inner end of a short shaft in, which passes through one of the standards a; on
the outer end of the shaft is fixed a hand wheel n (see Figure 1) by turning which,
one way or the other, the yoke and brushes may be adjusted to any desired position
on the commutator as will be readily understood by reference to Figures 1 and 2.
The said hand wheel n is formed with a long hub as shewn in Figure 1 so that its.
rim is at some distance from the side or standard of the machine to enable it to be
conveniently grasped by the hand; the inner side of the said rim is perforated or
provided with series of indentations any one of which may be engaged with the
point of a spring bolt u which projects from the side of the frame of the machine:
as shewn, so as to hold the wheel firmly at any of the several positions corresponding
with the said notches to which the wheel may be turned as will be understood. These
notches as will now be readily observed constitute points of graduation corresponding
to fixed definite changes in position of the brushes on the commutator and
representing definite variations in the force of the current suited for a greater or
less amount of work. The rim of the hand-wheel is graduated or marked with
numbers or other indications corresponding in position with the engaging notches
and shewing the value of each adjustment. Thus in the present generator which
is designed for feeding electric arc lamps the graduations on the hand wheel
represent a range of adjustment for from one to ten lamps. Hence if the hand
wheel is turned so that the 10 figure and notch is coincident with the spring
bolt u the brushes will be set to their maximum position and will convey the full
maximum current of the machine sufficient to properly maintain the maximum
number of 10 lamps. If any less number of lamps is desired the wheel can be
turned till the notch and number corresponding to the desired number of lamps is.
coincident with the bolt, and the current will be thus properly adjusted for such
number and so on down to the lowest number and the parts will at the same time
be firmly held at the desired adjustment as long as required as will be readily
understood.
Hence by this means it is not necessary to run the full number of lights and use
a maximum amount of power when only a small number of lights may be required
and for which a smaller amount of power would suffice but by this regulating
device the operator or user of the machine is enabled, without the necessity for any
skill or calculation, to adapt the machine in a certain and simple manner for any
desired duty where it will give only the amount or number of lights desired and
use only a corresponding amount of power which has heretofore been very desirable
in the arc system of electric lighting.
:
It will be noted on reference to Figure 3 that the graduations of the different.
numbers of lights are not at regular but at irregular intervals, the intervals at the
minimum end of the scale for a small number of lights being quite short or close
together but much longer at the maximum end for the large number of lights while
the intervals increase rapidly in length from each end toward the middle of the
scale. These graduations will vary somewhat in different machines according to
individual peculiarities as before mentioned but will always have the irregular
character above noted and hence each machine should be graduated independently
and by absolute test before being sent out. This may be readily done as follows
that is to say. The machine is set in motion and put in circuit with one lamp and
the brushes are then adjusted by moving the hand wheel n (the rim of which is as
yet left blank) until the current emitted is sufficient to maintain an arc or light of
normal or standard power in the one lamp. When this result is reached the point.
on the rim of the wheel which coincides with the bolt u is marked by a prick-
punch or scribe, and this constitutes the graduation or adjustment for one lamp.
Two lamps are then switched into circuit and the hand wheel turned so as to
advance the brushes further toward the maximum position until the current is
increased sufficiently to produce a standard arc in both lamps, when the position

page_text: thus formed in marked on the wheel as before and the graduation for each
additional lamp up to the maximum number is thus formed, one after the other, in
the same way, after which the indentations are bored at the points marked and
the figures representing the value of the graduations are stamped on the front over
the indentations, as shewn in Figure 3. In this way the adjustment for each
machine for any number of lights is rendered perfectly accurate, and the operator
has only to set the regulator, as its graduations indicate for the corresponding.
number of lights, which may be done in a very quick and easy manner and requires
no skill or special care, thus embodying a most important improvement in generators
for electric lighting or other distributed electrical work.
I wish it to be understood that I do not make any claim to the principle of
adjusting the angular position of the brushes on the commutator of a "Gramme"
armature for the purpose of regulating the force of the current emitted thereby as
this principle is well known and is at present employed in several ways. For
instance the brush holder has been made movable about the commutator and
provided with a set screw whereby it can be held at different angular positions,
and, in some cases, regular circumferential or angular graduations are provided
whereby the brushes might be set at angles of different degrees; again in certain
systems of incandescent electric lighting, it has been common to automatically
shift the position of the brushes by an automatic magnetic regulating device so
as to regulate the current in the general light circuit.
It will be readily noted, however, that my improvements are distinct from any of
these arrangements in that I provide a regulating device for manually shifting the
position of the brushes having fixed definite points of graduation or engagement
representing fixed definite changes of current corresponding to certain varying
numbers of lights or other definite changes of duty so that the unskilled operator
can instantly and easily adjust the machine for the desired duty, without need of
calculation or danger of error and without waste of power or over production
of current which latter is an important element of safety in operating light
circuits.
It may also be noted that the special construction of my regulator presents
advantages in safety, simplicity, and efficiency, for, as the manipulating device or
hand wheel n is placed on the outside of the machine remote from the brush holder:
it is very conveniently reached and operated by the hand and there is no liability
of receiving a shock in so doing; whereas were the manipulating device placed
within the machine near the brush holder or commutator, it would be in a less
convenient position and the operator would be sometimes likely in a moment of
inadvertence to touch a positive and negative part at the same time in proceeding
to make the adjustment and thus receive a shock; this is completely obviated by
my arrangement.
It will be readily understood that while I prefer the special manipulating and
engaging devices shewn, yet any other suitable manipulating and engaging devices
might be substituted without departing from the main feature of my Invention.
For instance a hand lever or screw might be used in place of the hand wheel either
at the outside or inside of the machine, and many other slight modifications might
be adapted without departing from the principal feature.
The special construction of the catch bolt u is shewn best in Figure 4; the
movable bolt part has the form of a grooved sleeve and slides over a hollow stud u':
screwed into the side frame of the machine. A spring enclosed within the hollow
of the sleeve and stud bears at one end against the said stud and at the opposite
end upon the sleeve tending constantly to press the solid point of the sleeve into
engagement with the notches o in the rim of the wheel. By pressing the sleeve.
back the point of the sleeve may be disengaged from one notch, the wheel turned.
around to the desired point and the sleeve allowed to spring into engagement with
the desired notch, thereby holding the wheel positively in the desired position as
will be understood.
.. Having thus fully described the said Invention as communicated to me by my.

page_text: foreign correspondent, and the manner of performing the same, I wish it understood
that I claim.
First. In an electric generator (of the so called "Gramme" type) a regulating device
for manually shifting the position of the commutator brushes, the said device being
provided with points of graduation or engagement to which the said brushes may
be adjusted, and representing definite changes of current corresponding to varying
numbers of lights or other definite changes of duty substantially as herein described
and for the purpose specified.
Second. In an electric generator substantially as herein described the com-
bination with movable brushes adjustable around the commutator, of a hand wheel
or lever operatively engaged with the movable brushes or with the brush-holder
and a series of definite points of engagement along its range of motion into which
the said lever may be moved and held, to set and hold the brushes at different
definite positions, substantially as, and for the purpose, set forth.
Third. In an electric generator, the combination with a movable brush-holder
arranged within the framework of the machine, of a manipulating device opera-
tively engaged with the brush-holder and having its manipulating or grasping
portion arranged on the exterior of the machine, and a catch or retaining device for
holding the said manipulator in the different positions to which it may be set,
substantially as herein described.
Fourth. The combination, in an electric generator, of the movable toothed brush-
holder i, pinion 7, shaft k, and hand wheel n, with a catch to hold the said hand
wheel in different positions, substantially as described.
Fifth. In an electric generator, the hand wheel n, provided with engaging points
or notches on its rim, and a fixed spring-bolt or catch to engage there with, in com-
bination with a movable brush holder and an operative connection between the
same and the hand wheel, substantially as, and for the purpose set forth.
In witness whereof I the said William Robert Lake have hereunto set my
hand and seal this Twenty sixth day of May in the year of our Lord
One thousand eight hundred and eighty two.