Improvements in or relating to the Automatic Regulation of Dynamo-electric Machines.
Year: 1891

page_text: Date of Application, 22nd Apr., 1891
Complete Specification Left, 22nd Jan., 1892-Accepted, 27th Feb., 1892
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Automatic Regulation of
Dynamo-electric Machines.
A communication from WILLIAM STONE, of Mary Street, West Beach, St. Kilda,
near Melbourne, in the Colony of Victoria, Electrician.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., do hereby declare the nature of this invention to be as follows:-
:-
This invention relates to the regulation of the current generated in that class of
dynamos known as "open-coil dynamos" that is, those machines whose armatures
have a number of coils which are independent of each other and not connected
together and each of which coils has its own independent commutator segments.
The separate coils or sets of coils may however be connected in any desired
manner by means of suitable connecting wires and brushes pressing on the
commutator.
The regulation of the current is mainly effected by rocking the line of commutation
relatively to the resultant field in such a manner that the electro-motive force set
up in some of the armature coils will be in opposition to the main electro-motive
force of the machine or that set up in some of the remaining coils.
The invention consists essentially in the employment of three brushes or sets of
brushes mounted at fixed angular distances apart upon a movable frame connected
to the armature of a long-pull magnet or solenoid whose coils are inserted in the
main circuit, said brushes or sets of brushes being so arranged that two of them,
which are directly electrically connected together, press upon the commutator one
on either side of the diametric line on which the other brush or set of brushes is
arranged.
The angle between the two brushes or sets of brushes which are directly
electrically connected together is such that the normal current is started in each
coil during the time it is short-circuited by the brushes so that no sparking occurs
when the coils are thrown into the main circuit.
The rocking-brush-carrying frame is carried in a standard in such a manner that
it can rock easily about the axis of the commutator.
The core or armature of a long-pull electro-magnet or solenoid is connected
preferably by means of a connecting rod to an extension or arm of the rocking
frame which is also connected with a dash-pot or equivalent device for the purpose
of preventing too sudden movements of the rocking frame.
A clutch or brake is provided so as to act on the core of the long-pull electro-
magnet or solenoid so as when necessary to arrest its movement.
Relay bobbins or solenoids are mounted on a brass or other suitable saddle and
are preferably so wound or built up in a practically taper form and the cores are
so made that the sucking action on the cores will be practically uniform throughout
at least say one quarter inch of the cores' movement. Attached to the cores of the
relay-solenoids are three contacts which dip each into one of three mercury cups.
When the current is of the normal value these contacts cause a portion of the
current otherwise passing through the coils of the long-pull magnet or solenoid to
be shunted through the coils of the clutch and when the current is too great they
open the shunt to the long-pull magnet or solenoid. When the current is too small
the relay-contacts effect the short-circuiting of the coils of the long-pull magnet or
solenoid.
A suitable manner of constructing the commutator to be used with the arrange-
ment of brushes before described is as follows :-
Ja muination on the inner face are clamped

page_text: -
between insulating washers by means of a brass sleeve and nut. Holes are bored
in the insulating washers for the reception of the wires for connecting the segments
to the armature coils and tightly fitting ebonite tubes are forced into the holes after
the commutator has been put together.
The copper segments are secured in the usual manner.
The alternate pairs of the armature coils form practically independent armatures
each having its own split ring commutator and the alternate armatures are so
connected to their commutator that they tend to drive the current in the reverse
direction along the line of commutation.
The
In the disc form of commutator the commutator is composed of say four split
rings or eight segments each of which segments embraces nearly 180° of arc.
gaps between the successive pairs of segments are placed each at an angle of 45° in
advance of the previous one.
The terminals of alternate coils on the armature are connected to their respective
commutator segments in the reverse direction i.e. the current is driven along the
line of commutation in the reverse direction by each alternate pair of armature
coils. This method enables all the armature coils to be connected in series by
means of the commutator brushes and obviates the necessity for using cross
connecting wires between them.
Two individual brushes form the terminals of the armature and other individual
brushes are for the purpose of connecting the armature coils in series and the
elimination of sparking. Certain of these brushes are connected in pairs electrically
by means of suitable conductors while another of the brushes is not electrically con-
nected to any other part of the apparatus excepting by contact with the commutator.
The three sets of brushes as before stated are mounted on the rocking frame but
are electrically separated from it.and from each other by means of suitable insulating
material.
When the brushes have been properly adjusted all of them will move together
with the rocking frame about the axis of the commutator, this rocking being
effected by the long-pull magnet or solenoid any motion of the core or armature of
which will cause the rocking frame and with it the brushes to move about the axis
of the commutator.
The coils of the long-pull magnet or solenoid and relay are each preferably
provided with a high resistance non-inductive shunt or coil to prevent sparking at
the contacts. .
When the current is of the normal value the clutch coils act as a partial shunt to
the coils of the long-pull magnet or solenoid which under these conditions is just
sufficiently excited to enable it to maintain the whole of the movable mechanism
in equilibrium and the current passing through the clutch coils brings it into action.
Should the current become too great the armature of the relay so operates the
contacts as to cause the clutch to release the core of the long-pull magnet or
solenoid and at the same time send the whole current through the coils of the said
long-pull magnet or solenoid so that it raises its armature or core and rocks the
brushes in the direction for diminishing the electro-motive force of the machine.
The motion of the brushes will be continued till the current again assumes its
normal value and the clutch comes into operation.
Should the current become too small the relay armature descends and so operates
the contacts that both the long-pull magnet or solenoid and clutch have their coils
short circuited. Under these conditions the clutch releases the armature or core of
the long-pull magnet or solenoid and the weight of said core causes the brushes to
rock in the direction for increasing the electro-motive force of the machine. The
rocking continues till the current assumes its normal value when the clutch again
comes into operation.
When adapting the regulator to existing machines having armatures wound in
the usual manner the diametrically opposite coils must be coupled in parallel circuit.
If this were not done excessive heating of the armature coils would result as they
are always maintained in series by the form of commutator adopted.

page_text: With the usual arrangement of brush commutator one pair of armature coils is
always in series with two similar pairs in parallel hence the resistance of the
armature between the terminal brushes will be three times that of one bobbin. In
the arrangement used with the regulator three pairs of coils are always in series
between the terminal brushes. Hence if existing armatures were used without
coupling the pairs of coils in parallel the total resistance of the armature between
the terminal brushes would be that of six bobbins or just double its resistance when
working in the ordinary manner. But if the coils are coupled in parallel the
resistance of the armature between the terminal brushes will be one fourth of the
above (i.e. = resistance of 1 bobbins). With the machine coupled up in this
way it can run about of the normal number of lamps when driven at the normal
speed.
If armatures are wound to suit the regulator the electro-motive force of the
machine would be the same as now obtained.
From the foregoing description it will be seen that the regulation is effected in
part by the variable demagnetising influence of the armature field on that of the
field magnets produced as the relative position of the two fields is changed by the
mechanism for automatically altering the line of commutation. The regulation is
however mainly effected by the rocking of the line of commutation relatively to the
resultant field in such a manner that the electro-motive force set up in some of the
armature coils will be in opposition to the main electro-motive force of the machine;
the magnitude of the opposing electro-motive force and the time during which it
acts is determined by the position of the brushes which are automatically rocked
about the axis of the commutator.
It will further be seen from the foregoing description that the sparking at the
commutator is prevented by always maintaining the armature coils on closed circuit
so as to obviate the difficulty of effecting commutation at points other than on the
neutral axis.
I do not limit myself to the particular arrangement of brushes and reversed
connections of the alternate armature coils with their respective commutator
segments for the purpose of connecting the several armature coils in series here
described as the same purpose may be effected by coupling all the armature coils to
their respective commutator segments in the same way and making the requisite
connections between the various sections of the commutator by means of suitable
conductors and moreover instead of using two connected brushes as before described
I may use one thick brush and in many other ways I can modify the before
described arrangement without departing from the spirit of the invention.
Dated this 22nd day of Anril 1801
COMPLETE SPECIFICATION.
Improvements in or relating to the Automatic Regulation of
Dynamo-electric Machines.
A communication from WILLIAM STONE, of Mary Street, West Beach, St. Kilda,
near Melbourne, in the Colony of Victoria, Electrician.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement :-
This invention relates to the regulation of the current generated in that class of
dynamos known as "open-coil dynamos" that is, those machines whose armatures
have a number of coils which are independent of each other and not connected
together and each of which coils has its own independent commutator segments.

page_text: The separate coils or sets of coils may however be connected in any desired
manner by means of suitable connecting wires and brushes pressing on the
commutator.
The regulation of the current is mainly effected by "rocking" the line of com-
mutation relatively to the resultant field in such a manner that the electro-motive
force set up in some of the armature coils will be in opposition to the main
electro-motive force of the machine or that set up in some of the remaining
coils.
The invention consists essentially in the employment of three brushes or sets of
brushes mounted at fixed angular distances apart upon a movable frame connected
to the armature of a long-pull magnet or solenoid whose coils. are inserted in the
main circuit, said brushes or sets of brushes being so arranged that two of them,
which are directly electrically connected together, press upon the commutator one
on either side of the diametric line on which the other brush or set of brushes is
arranged.
The angle between the two brushes or sets of brushes which are directly
electrically connected together is such that the normal current is started in each
coil during the time it is short circuited by the brushes so that no sparking occurs
when the coils are thrown into the main circuit.
The invention will be best understood by reference to the accompanying drawings,
in which
Fig. 1 is an end elevation of part of a brush dynamo with my improvements
applied thereto and of which
Fig. 2 is a horizontal section with parts of the brushes broken away the better to
illustrate the construction of the commutator which in this example is of cylindrical
form.
Fig. 3 is an elevation presented in the same direction as that of Figure 1 of the
brush regulating device detached from the dynamo.
Fig. 4 is an elevation of the upper portion of the same device showing the side at
right angles to that shown in Fig. 3 and illustrating the solenoid, clutch and
relay.
Fig. 5 is a plan of Fig. 4 showing the relay.
Fig. 6 is a horizontal section on the line 6-6 of Fig. 3 showing the clutch.
Fig. 7 is a side elevation of a modified form of relay.
Fig. 8 is a diagrammatic view illustrating the manner of connecting the armature
coils with each other and with the plates or segments of the commutator which in
this diagram is represented in the form of a disc.
Fig. 9 is a diagrammatic view illustrating generally the arrangement of the
conductors, contacts and other operative parts of my improvements.
Like letters indicate like parts throughout the drawings.
In Figures 1 and 2, A is the standard which supports the rocking-brush-carrying
frame B. The rocking frame B which directly supports the sets of brush
holders CD is supported preferably on anti-friction rollers A¹ carried in the
standard A in such a manner that it can rock easily about the axis of the com-
mutator Z. Attached to the rocking frame B is the segmental arm E on which is
mounted the adjustable set of brush holders F which can be moved to and clamped
at any part of the segmental arm E by means of the set screw G.
In Fig. 1 the collecting brushes are diagrammatically represented by single lines.
H is the long pull electro magnet or solenoid shown in detail in Figs. 3 to 6.
Its movable armature I is connected preferably by means of a connecting rod J to
an extension or arm K of the rocking frame B. The arm K also serves as an
extra support for the segmental arm E. The plunger of a dash-pot L or equivalent
device secured preferably to the bed-plate of the machine, is attached to the con-
necting rod J and the dash-pot secured to the bed plate of the machine for the
purpose of preventing too sudden movements of the rocking frame B.
The long pull clectro magnet or solenoid H is clamped to the field magnet yoke
by means of one of the bolts or screws that hold the field magnet limb.

page_text: The outer case M of the long pull electro-magnet or solenoid is made of preferably
ordinary wrought iron pipe the lower end of which is turned out to a taper as
shown by the dotted lines xx. The top end is partially closed by a preferably
wrought iron washer N having a hole in the centre. The armature I consists of a
rod of wrought iron turned preferably to the form shown and furnished at the lower
end with an iron disc O just a little smaller in diameter than the internal diameter
of case M.
Preferably three brass wedges P are fastened in the taper end of the case M to
form guides against which the disc O at lower end of the armature slides. Notches
are provided in the edge of the disc O to correspond with the brass wedges which
latter therefore serve to prevent the armature from turning as well as to maintain
it always in the centre of the magnet case thus ensuring its freedom of motion.
A preferably brass block Q is screwed to the top of the armature and over it is
pushed the tightly fitting brass tube R. The external diameter of the brass tube R
is such that it can just pass freely through the hole in the washer N which therefore
forms a guide for the top end of the armature.
The exciting coil of the long pull magnet is wound on the preferably brass
bobbin S. The bobbin is retained in position by screws passing through the
washer N into its top flange. The lower end of the bobbin is steadied by its flange
being turned to fit the tapered part of the iron case.
The clutch cores T are fastened to the washer N by means of preferably brass
screws and are magnetically separated from N by the thick non-magnetic
washers U.
The thick iron disc V forms the yoke of the clutch magnet and at the same time
shields the cores of the relay from the variable magnetic influence of the long pull
magnet or solenoid as its armature changes its position during the process of
regulation. The pillars W are preferably of brass and simply serve as supports
for the iron plate V. The spring X keeps the armature T' of the clutch away
from the brass tube R when there is no current passing through the clutch coils T³,
but on the current passing through the clutch coils the armature T' is forcibly
drawn against the tube R. The portion of the clutch armature T' which is drawn
against the tube R is faced with hard leather or some other suitable frictional
material.
The relay bobbins or solenoids Y are mounted on a brass or other suitable
saddle Z¹ and are preferably so wound or built up in a practically taper form and
the cores a are so made that the sucking action on the cores will be practically
uniform throughout at least say one quarter inch of the cores' movement. Attached
to the yoke a¹ which connects the movable cores a at their lower ends is a pillar b
which supports the three branch contact bridge which at the same time is insulated
from the pillar b. The three branches c' c³ ³ of the contact bridge c dip each into
one of three preferably ebonite mercury cups d. The three brass pillars e¹ e² e³ are
mounted on the blocks of ebonite in which the mercury cups are formed and form
the terminals through which contact is made with the mercury in the cups. A
small stud or disc attached to the yoke a' of the relay is provided on which
weights can be placed for the purpose of regulating the relay to control for the
required current.
In the relay shown in Fig. 7 the contacts are at ghi. When the current is of
the normal value the contacts g and i are made and h is broken; under these con-
ditions a portion of the current otherwise passing through the coils of the long pull
magnet or solenoid H is shunted through the coils of the clutch. When the current
is too great the contacts at g and h are broken thereby opening the shunt to the
long pull magnet or solenoid H. When the current is too small the relay contact
at i is broken and the circuit at h is made the effect being to short circuit the coils
of the long pull magnet or solenoid H.
A suitable manner of constructing the commutator shown in Fig. 2 is as
follows:-
The preferably brass segments ; each with a dovetailed projection on the inner

page_text: face are clamped between the insulating washers by means of a brass sleeve and
nut . Holes are bored in the insulating washers k for the reception of the wires
for connecting the segments; to the armature coils and tightly fitting ebonite tubes
are forced into the holes after the commutator has been put together.
The preferably copper segments j' are secured in the usual manner.
On referring to Fig. 8 it will be seen that alternate pairs of the armature coils
form practically independent armatures each having its own split ring commutator
and that the alternate armatures are so connected to their commutator that they
tend to drive the current in the reverse direction along the line of commutation.
The commutators shown in Figs. 8 and 9 are of ring or disc form.
In Fig. 9 the commutator is composed of say four split rings or eight segments j¹
each of which segments embraces an arc of nearly 180°. The gaps between the
successive pairs of segments are placed each, at an angle of 45° in advance of the
previous one.
The terminals of alternate coils on the armature as shown in Fig. 8 are connected
to their respective commutator segments in the reverse direction i.e. the current
is driven along the line of commutation in the reverse direction by each alternate
pair of armature coils. This method enables all the armature coils to be connected
in series by means of the commutator brushes and obviates the necessity for using
cross connecting wires between them.
-
The two individual brushes + C¹ and OC¹ form the terminals of the armature
and the remaining individual brushes C' D D F F are for the purpose of con-
necting the armature coils in series and the elimination of sparking. The
brushes D F, D³ F2 are connected in pairs electrically as shown by means of
suitable conductors z. The brush C¹ is not electrically connected to any other
part of the apparatus excepting by contact with the commutator. The three
sets of brushes as before stated are mounted on the rocking-frame B but are
electrically separated from it and from each other by means of suitable insulating
material.
The two sets of brushes + C₁ C¹ - C¹ and D¹' D' are fixed at a suitable angular
distance from each other on the rocking frame B E. The other set of brushes F
can be moved through a small angle with reference to the others for the purpose of
adjustment by the maker or re-adjustment if it is desired to alter the value of the
normal current to be taken from the machine, the set screw G Fig. 1 being provided
for this purpose.
When the brushes FF have been properly adjusted the whole
system of brushes will move together with the rocking frame about the axis of the
commutator, this rocking being effected by the long pull magnet or solenoid H any
motion of the core or armature of which will cause the rocking frame B and with it
the brushes, to move about the axis of the commutator.
The coils of the long pull magnet or solenoid H and relay Y are each preferably
provided with a high resistance non-inductive shunt or coil H* T* respectively to
prevent sparking at the contacts c¹ c³.
In the arrangement of circuit shown in Fig. 9 the current passes from the
positive brush + C₁ through the field magnet coils F M the lamp circuit L C the
relay coils Yand the coils of the long pull magnet or solenoid H in series returning
by the negative brush C' to the dynamo armature.
When the current is of the normal value the relay contacts c³ ³ are in the
position in which they are shown in Fig. 9 and the clutch coils T' act as a partial
shunt to the coils of the long pull magnet or solenoid H which under these con-
ditions is just sufficiently excited to enable it to maintain the whole of the movable
mechanism in equilibrium and the current passing through the clutch coils T
brings it into action.
Should the current become too great the armature of the relay Y is drawn up
till the contact at c³ is broken. This causes the clutch T¹ T' to release the core of
the long pull magnet or solenoid H and at the same time sends the whole current
through the coils of the said long pull magnet or solenoid H so that it raises its
armature.or.core.I and so rocks or moves the brushes in the direction for diminishing

page_text: the electro-motive force of the machine. The motion of the brushes will be
continued till the current again assumes its normal value and the clutch comes
into operation.
Should the current become too small the relay armature a¹ descends till the
contact at c' is closed when both the long pull magnet or solenoid H and clutch T'
have their coils short circuited. Under these conditions the clutch releases the
armature or core I of the long pull magnet or solenoid H and the weight of said
core causes the brushes to rock or move in the direction for increasing the electro-
motive force of the machine. The rocking continues till the current assumes its
normal value when the clutch T T again comes into operation.
When adapting the regulator to existing machines having armatures wound in
the usual manner the diametrically opposite coils must be coupled in parallel
circuit. If this were not done excessive heating of the armature coils would result
as they are always maintained in series by the form of commutator adopted.
With the usual arrangement of brush commutator one pair of armature coils is
always in series with two similar pairs in parallel hence the resistance of the
armature between the terminal brushes will be three times that of one bobbin. In
the arrangement used with the regulator three pairs of coils are always in series
between the terminal brushes. Hence if existing armatures were used without
coupling the pairs of coils in parallel the total resistance of the armature between
the terminal brushes would be that of six bobbins or just double its resistance when
working in the ordinary manner. But if the coils are coupled in parallel the
resistance of the armature between the terminal brushes will be one fourth of the
above (i.e. = resistance of 1 bobbins). With the machine coupled up in this
way it can run about of the normal number of lamps when driven at the normal
speed.
If armatures are wound to suit the regulator the electro-motive force of the
machine would be the same as now obtained.
From the foregoing description it will be seen that the regulation is effected in
part by the variable demagnetising influence of the armature field on that of the
field magnets produced as the relative position of the two fields is changed by the
mechanism for automatically altering the line of commutation. The regulation is
however mainly effected by the "rocking" of the line of commutation relatively to
the resultant field in such a manner that the electro-motive force set up in some of
the armature coils will be in opposition to the main electro-motive force of the
machine; the magnitude of the opposing electro-motive force and the time during
which it acts is determined by the position of the brushes which are automatically
rocked about the axis of the commutator.
It will further be seen from the foregoing description that the sparking at the
commutator is prevented by always maintaining the armature coils on closed circuit
so as to obviate the difficulty of effecting commutation at points other than on the
neutral-axis.
I do not limit myself to the particular arrangement of brushes and reversed
connections of the alternate armature coils with their respective commutator
segments for the purpose of connecting the several armature coils in series here
described as the same purpose may be effected by coupling all the armature coils
to their respective commutator segments in the same way and making the requisite
connections between the various sections of the commutator by means of suitable
conductors and moreover instead of using two connected brushes such as F¹ and D¹
or F and D' I may use one extended brush and in many other ways I can modify
the before described arrangement without departing from the spirit of the
invention.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner
the same is to be performed I declare that what I claim is,-
1. Regulating the current of a demo he "rooking" the line of commutation

page_text: relatively to the resultant field in such a manner that the electro-motive force set
up in some of the armature coils will be in opposition to the main electro-motive
force of the machine or that set up in some of the remaining coils.
2. The combination in an open coil dynamo electric machine of a suitable com-
mutator with a system of three brushes or sets of brushes mounted so as to have.
fixed angular positions with reference to each other certain of said brushes being
electrically connected in pairs so as to act as one extended brush including within
its contact a suitable portion of the circumference of the commutator, the system of
brushes as a whole being so arranged that it can be automatically rocked for the
purpose of regulation substantially as described.
3. The combination in an open coil dynamo of one or more split ring commutators
substantially as described and shown in Figures 8 and 9 of the accompanying
drawings of a system of three brushes or sets of brushes or their electrical equivalent
such as one extended brush mounted on a rocking frame at fixed relative angular
positions with apparatus for automatically rocking the same for the purpose of
regulation substantially as described.
4. The combination in an open coil dynamo with a commutator substantially as
described and illustrated in the accompanying drawings of a system of three brushes
or sets of brushes for the prevention of sparking at the commutator during com-
mutation by arranging the three brushes or sets of brushes in such a manner that
the armature coils are always maintained on closed circuit and remain on short
circuit for a suitable time substantially as described.
5. The combination with an open coil dynamo of a commutator a
long pull
magnet or solenoid such as H I clutch such as T T' T' and relay such as Y a a'
substantially as described and illustrated in the accompanying drawings.
Dated this 22nd day of January 1892.
ALFRED J. BOULT,
Chartered Patent Agent.