IMPROVE- MENTS IN APPARATUS FOR PRODUCING, MEASURING, AND DISTRIBUTING ELECTRIC CURRENTS
Year: 1882

page_text: LETTERS PATENT to John Macintosh Mackay Munro, of Glasgow, in the
County of Lanark, North Britain, Electrician, for an invention of "IMPROVE-
MENTS IN APPARATUS FOR PRODUCING, MEASURING, AND DISTRIBUTING
ELECTRIC CURRENTS."
PROVISIONAL SPECIFICATION left by the said John Macintosh Mackay
Munro at the Office of the Coinmissioners of Patents on the 13th July 1882.
JOHN MACINTOSH MACKAY MUNRO, of Glasgow, in the County of Lanark, North
Britain, Electrician "IMPROVEMENTS IN APPARATUS FOR PRODUCING, MEASURING,
AND DISTRIBUTING ELECTRIC CURRENTS
"
This Invention has for its object to improve and render more efficient and
satisfactory apparatus employed for producing, measuring, and distributing electric
currents.
In constructing dynamo machines for producing electric currents it is sought
by this Invention to arrange the active surfaces of the field magnets so as to
surround to a greater extent than in ordinary machines the coils of the rotating
armature or armatures; and in carrying out this part of the Invention the iron
cores of the armatures may rotate or be stationary, or they may in some cases
be dispensed with.
When continuous currents of moderate quantity are required the machine is
made, according to one modification, with several armature rings mounted on
metal spokes with open spaces between to favor the escape of heat. Each iron
core or ring is composed of several cylindrical bands or hoops of soft iron which
are insulated from each other; and coils of insulated wire are wound round each
core as in the Gramme machine, but U-shaped copper pieces are placed between
the coils, the legs of such pieces being wedge-shaped to fill up the interstices, and
the pieces being connected to the coils so as to be included in the circuit or circuits.
No part of, nor piece of iron attached to, the core projects through the coils as in
some machines. The field magnets are made with curved middle parts and straight
ends, and exciting coils are wound round both ends of a number of the bars placed
TD 1071
"

page_text: close or near together. The coils are arranged so as to make the middle curved
parts the active or polar parts and the magnets are arranged in two opposite sets
with the armatures rotating between them within the curved parts. The several
armature rings are placed somewhat apart, and some of the magnet bars have their
middle curved parts of a smaller curvature so as to enter in between the rings and
act on their sides whilst the other bars have their middle parts of a larger curvature
so as to act on the circumferential parts of the rings.
In another modification increased extent of action is obtained by arranging field
or stationary magnets to act inside of the rotating armature in a peculiar manner.
The armature is carried on a tubular shaft or on two tubular bosses and is in the
general form of a cylinder, the essential part of which consists of insulated copper
rods or wires of extra thickness. At the circumference the rods run in longitudinal
planes but are bended inwards and outwards alternately so as to combine to form a
kind of circularly grooved surface, and the external field magnets are arranged so
that some of the bars project into the grooves and others act on the parts between
the grooves. Field or stationary magnets are arranged inside of the cylinder in a
similar way, and are carried upon a central stationary shaft passing through the
tubular shaft or bosses carrying the armature. The ends of the copper rods are
themselves extended across the cylinder ends, or are connected to each other in
diametrically opposite pairs by wires; being also of course connected to commutator
details as in other machines. The internal field magnet bars have their middle
parts aro-shaped to the extent of nearly a semicircle, and their ends are bended
inwards and wound with exciting coils, keepers being placed between the ends to
prevent their acting undesirably on the outer middle parts. The external field
magnets may be like those of the first modification, or they may have their ends
bended back over their middle parts in a manner analogous to the arrangement of
the internal field magnets.
Each dynamo machine is by this Invention fitted with a device for automatically
throwing it out of circuit when it ceases to be driven and which may also be
arranged to act when the resistance is above or below certain strengths, or to vary
the resistance in proportion to the speed at which the machine is driven. In one
simple modification the device consists of a small centrifugal governor fitted on the
main shaft or on a shaft geared thereto, the sleeve or part of this governor which
moves according to the speed being connected to a switch, with which there may
in some cases be combined an electro magnet or a solenoid and core.
In cases in which it is wished to change the direction of the electric currents
either frequently or at long intervals there are fitted in connection with the main
shaft or a shaft suitably geared thereto, two pairs of arc-shaped commutator bars
or strips one of each pair being connected to what is ordinarily the positive wire
and the other of each pair to the negative wire. On the shaft are two arms which
are in electric connection respectively with the positive and negative terminals of
the machine and which as the shaft rotates move in contact with the bars or strips.
Sparking is avoided by arranging the parts so that each fresh contact is completely
made before the previous contact is broken.
For measuring or indicating the strength of an electric current a lever mounted
on knife edges carries coils at its ends through which is passed the current to be
measured (and which may be a shunt current from a stronger circuit). Each of
these lever coils is between a pair of stationary coils with or without iron cores,
such stationary coils having the saine current passing through them. The effort of
the lever to move by the action of the currents is balanced by an adjustable weight
and the strength of the current can be calculated from the position of the weight.
The lever may be arranged with parallel-motion links to keep the coils parallel, or
they may be suspended by cords from the opposite sides of a pulley centered on
anti-friction wheels or knife edges. In another modification the lever has one or
more weights connected to it, and placed in such position or positions relatively to
the fulcrum as to produce equilibrium for different strengths of current by assuming
different positions, Instead of the lever being arranged to turn on knife edges

page_text: about a horizontal axis it may be arranged as a torsional balance with bifilar
suspension. The improved indicating or measuring apparatus may also be used
for setting in action a variety of apparatus of well known kinds when a
predetermined strength of current is exceeded, the lever in such case moving into
contact with a stop and thereby completing an electric circuit so as to work an.
alarm bell, or set clockwork in motion, or actuate an electro-magnet or solenoid
and core so as to move switches of safety shunts or of resistance apparatus.
A recording measuring device is by this Invention made with a two-chambered
vessel somewhat like an hour glass and containing mercury which flows through a
small port between the two chambers, such port being controlled by a valve which
is adjusted according to the strength of the electric current to be measured, by
apparatus of the kind last hereinbefore described. Electro-magnets or clockwork
details are arranged to invert the vessel whenever the mercury flowing into the
chamber which is lowermost reaches a certain level therein, the mercury then
making contact with the end of an electric conductor provided for the purpose and
completing a circuit which sets the electro-magnet or clockwork in action. The
inversions are recorded by counting mechanism and the combined apparatus.
constitutes an electric meter.
In improved apparatus comprised in this Invention for distributing the electrio
currents, the details of switches are arranged so as to be less liable than those
hitherto used to be left partly open. The movable parts or handles of the improved
switches are arranged either to drop by their own weight or to turn over or down
by weight when arranged as levers; and in some modifications contact is made by
the entering of a movable part in between a pair of tongues of spring metal, these
tongues clipping and holding the movable part sufficiently to prevent separation
by the gravitation of the movable part. In some cases the clip tongues are
insulated from each other and connected to the separate conductors of the main or
branch circuit, and the circuit is completed by the insertion of a movable piece of
metal between the tongues. In other cases both of the clip tongues are connected
to one conductor and the other conductor is connected to the movable part of the
switch so that when this is turned or raised to engage with the clip tongues the
current passes through the clip tongues and onward through the movable part of
the switch. Instead of the clip tongues being the stationary part they may be on
the movable piece being moved up or turned into a position to embrace or clip a
stationary piece when making contact.
When a main conductor has connected to it several branches such for example
as those for a number of electric lights, each branch having a separate switch for
putting on or turning off the current, it is often desirable to turn off all the
branches by means of a single switch fitted to the main conductor and to be able
to turn on the main conductor again without turning on all the branches, so that
each of the lights or separate sets of the lights may be turned on separately and
only as required although all have been extinguished by shifting the main switch
only. To meet this requirement each branch switch is fitted with a weight or
spring which tends to open it, and an electro-magnet actuated by the current is
arranged to hold it when moved into the closed position. When the current is
turned off at the main conductor the several electro-magnets of the branch switches
lose their hold and the switches are opened by their springs or weights; but when
the main conductor is turned on again the branch switches remain open, each until
it is moved by hand into the closed position prior to which the electro-magnet has
no action on it.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Macintosh Mackay Munro in the Great Seal Patent Office
on the 12th January 1883.
JOHN MACINTOSH MACKAY MUNRO, of Glasgow, in the County of Lanark, North
Britain, Electrician. "IMPROVEMENTS IN APPARATUS FOR PRODUCING, MEASURING,
AND DISTRIBUTING ELECTRIC CURRENTS"
My said Invention has for its object to improve and render more efficient and
satisfactory apparatus employed for producing, measuring, and distributing electric
currents. In describing my improvements I shall when it appears necessary refer
to explanatory diagrams on three sheets of drawings which are hereunto
appended.
In constructing dynamo-machines for producing electric currents I seek to
arrange the active surfaces of the field magnets so as to surround to a greater
extent than in ordinary machines the coils of the rotating armature or armatures;
and in carrying out this part of my Invention the iron cores of the armatures
may rotate or be stationary, or they may in some cases be dispensed with.
When continuous currents of moderate quantity are required the machine is
made, according to one modification, with several armature rings mounted on metal
spokes with open spaces between to favor the escape of heat. Each iron core or
ring is composed of several cylindrical bands or hoops of soft iron which are insu-
lated from each other; and coils of insulated wire are wound round each core as
in the Gramme machine, but U-shaped copper pieces are placed between the coils,
the legs of such pieces being wedge-shaped to fill up the interstices, and the pieces
being connected to the coils so as to be included in the circuit or circuits. No
parts of, nor piece of iron attached to, the core projects through the coils as in some
machines. Figure, 1, is a plan; figure, 2, a horizontal section and figure, 3, a sido
elevation of one modification of my improved dynamo machine. Figures, 4, and 5,
are face views of copper pieces which I use to form the coils on the armature rings
such pieces being either combined with coils of ordinary copper wire or being
used exclusively in constructing the coils. Figure, 6, is a plan or edge view and
figure, 7, is a side view of a portion of an armature so formed. The iron core, C,
which is by preference formed with deep grooves as indicated in figure, 7, has a
number of the pieces, 5, put upon it with insulating material (not shown) between
them, and to admit of the pieces, 5, being got in, their outer cut parts are bended
sufficiently apart to get them on. The pieces, 4, are then inserted between the
outer parts of the pieces, 5, and are soldered thereto in a manner to form a con-
tinuous annular helix as will be understood from figure, 6. The field magnets, F,
are made with curved middle parts and straight ends as shown in figure, 8, and
exciting coils E, figure, 3, are wound round both ends each pair of the bars placed
close or near together. The coils are arranged so as to make the middle curved
parts the active or polar parts and the magnets are arranged in two opposite sets
with the armatures rotating between them within the curved parts. The several
armature rings are placed somewhat apart, and in one modification some of the
magnet bars have their middle curved parts of a smaller curvature. so as to enter.
in between the rings and act on their sides whilst the other bars have their middle
parts of a larger curvature as indicated by dotted lines in figures, 2, and 8, so as
to act on the circumferential parts of the rings. I however prefer to dispenso
with the outer bars indicated by dotted lines in figures, 2, and 8, and I apply
collector or commutator brushes, B, figure, 3, so as to bear directly on the circum-
ferential parts of the armatures these circumferential parts of the convolutions of
the coils being left bare or externally uninsulated for the purpose.

page_text: In another modification shown in figures 9, and 10, increased extent of action is
obtained by arranging field or stationary magnets to act inside of the rotating
armature in a peculiar manner. The armature is carried on a tubular shaft or on
two tubular bosses and is in the general form of a cylinder the essential part of
which consists of insulated copper rods or wires of extra thickness. At the circum
ference the rods run in longitudinal planes but are bended or cut inwards and
outwards alternately so as to combine to form a kind of circularly grooved surface,
and the external field magnets, F are arranged so as to project into the grooves
(and others might be arranged to act on the outer parts between the grooves).
Field or stationary magnets, S, are arranged inside of the cylinder in a similar way,
and are carried upon a central stationary bar or plate, P, formed with end journals
which pass through the tubular shaft or bosses carrying the armature and have
their ends fixed to the framing. The ends of the copper rods are themselves
extended across the cylinder ends or are connected to each other in diametrically
opposite pairs by wires; being also of course connected to commutator details as
in other machines or the brushes may bear on the circumferential parts as in
figure, 3. The internal field magnet bars have their acting parts are shaped to
the extent of nearly a semicircle, and their ends are bended inwards and wound
with exciting coils, the plate, P, acting as a keeper between the ends to prevent
their acting undesirably on the outer parts. The external field magnets, F, may
be like those of the first modification, or they may have their ends bended back
over their middle parts in a manner analogous to the arrangement of the internal
field magnets, S. The longitudinal copper bars of the armature may be made as
shown in figure, 9, or as shown in figure, 11, the acting faces of the field and
internal stationary magnets, F, S, being shaped to correspond. Or the internal
stationary magnets may consist of rings of the kind shown in figure, 14, having
diametrically opposite acting parts with exciting coils on the intermediate parts.
In another arrangement an alternate-current machine is obtained by suitably
connecting the ends of the longitudinal copper bars of the armature shown in
figure, 9, and by substituting for the field and internal magnets described and.
shown, the well known arrangement consisting of a series of numerous small
magnets presenting alternate poles. Figure, 12, shows the mode of connecting the
copper bars at one end of the multiple armature, the connections at the other end
being similar but joining those bars which are not joined at the end shown in
figure, 12 Figure, 13, is an edge view showing the multiple armature reduced
to what may be termed a single armature; and in this case the zig-zag copper
conductor has an iron ring between its. radial parts, which may be stationary or
rotate as part of the armature the alternating field magnets being placed facing
each disk face of the armature, but with the same poles on opposite sides of each
part. If in this arrangement a suitable commutator or other ineans is used to
render the current which excites the field magnets alternate, the current produced
by the machine will be continuous.
Each dynamo-machine is by this Invention, fitted with a device for automatically
throwing it out of circuit when it ceases to be driven and which may also be
arranged to act when the resistance is above or below certain strengths, or to vary
the resistance in proportion to the speed at which the machine is driven. In one
simple modification, the device consists of a small centrifugal governor fitted on
the main shaft or on a shaft geared thereto, the sleeve or part of this governor
which moves according to the speed being connected to a switch, with which there
may in some cases be combined an electro magnet or a solenoid and core. Instead
of the centrifugal governor a directly acting arrangement may be used. The
current meter shown. in figure, 15, and hereinafter described, wound with thick
.and fine wire, has the fine wire of the balanced coils connected between the positive
and negative terminals of the machine. The fixed coils have their fine wire and
their thick bands both parallel in the main circuit. The thin wire is always
unbroken; but if the machine should stop sending a current or the current be
overpowered by other machines the balanced coils will move until they break the

page_text: main circuit through the thick bands by withdrawing copper rods from mercury
cups. At the same time a contact is made which rings a bell. If the machine
recovers itself the current passing out through the fine wire of the fixed coils will
by its attraction on the current through the balanced coils remake the broken
contact.
For measuring or indicating the strength of an electric current I use the
apparatus shown in figure, 15, in which a lever, L, mounted on knife edges, K, carries
coils, A, at its ends through which is passed the current to be measured (and which
may be a shunt current from a stronger circuit). Each of these lever coils, A, is
between a pair of stationary coils, D, with or without iron cores, such stationary
coils being adjustable upon standards, G, and having the same current passing
through them. The effort of the lever to move by the action of the currents is
balanced by an adjustable weight, W, and the strength of the current can be
calculated from the position of the weight. The lever may be arranged with
parallel-motion links to keep the coils parallel, or they may be suspended by cords
from the opposite sides of a pulley centered on anti-friction wheels or knife edges.
In another modification the lever has one or more weights connected to it, and
placed in such position or positions relatively to the fulcrum as to produce
equilibrium for different strengths of current by assuming different positions.
Instead of the lever being arranged to turn on knife edges about a horizontal axis
it may be arranged as a torsional balance with bifilar suspension.
With the apparatus shown in figure, 15, or with similar apparatus I combine the
arrangement shown in figure, 16, in which a compound coil, H, is formed like
which the fixed coils, D, figure, 15, may be made and which may also be used for
an ordinary galvanometer. In this coil, H, portions of the coiled wire are kept
distinct and their ends are connected to contact plugs, J, arranged to be inserted
between a series of brass plates, M. Each plug, J, is made with diametrically
opposite contact springs for the two ends of its wire, and the current will pass in
one direction or the opposite through each coil according to the position in which
the plug is inserted between the plates, M. Thus when a weak current is to be
measured it may be made to pass in the same direction through all portions of the
coil, H, but when the current is strong the direction may be reversed in one or
more portions of the coil so as to reduce the action. The improved indicating or
measuring apparatus may also be used for setting in action a variety of apparatus
of well known kinds when a predetermined strength of current is exceeded, the
lever in such case moving into contact with a stop and thereby completing an
electric circuit so as to work an alarm bell, or set clockwork in motion, or actuate
an electro-magnet or solenoid and core so as to move switches of safety shunts or
of resistance apparatus.
A recording measuring device is by my Invention made as shown in figures, 17,
and 18, with a two-chambered vessel, V, somewhat like an hour glass and containing
mercury which flows through a small port between the two chambers, which port
may be controlled by a valve which is adjusted according to the strength of the
electric current to be measured, by apparatus of the kind last hereinafter described.
Electro-magnets, X, or clockwork details are arranged to invert the vessel
whenever the mercury flowing into the chamber which is lowermost reaches a
certain level therein, the mercury then making contact with the ends of electric
conductors, Y, provided for the purpose and completing a circuit which sets the
electro-magnets, X, or clockwork in action. The armature, Z, acts on the vessel, V,
through a wheel and pinion so that sufficient tilting movement may be obtained
from the small movement of the armature. The inversions are recorded by counting
mechanism and the combined apparatus constitutes an electrical meter.
I prefer to use the apparatus shown in figures, 17, and 18, simply as a time-
keeping appliance for effecting a certain movement at regular intervals in which
case the port between the two compartments of the vessel, V, does not require to be
variable; and I combine this apparatus with other apparatus as shown in figure, 19,
the tilting vessel, V, and its accessories being supposed to be inside of a casing, V.

page_text: In the combined apparatus the amount or strength of current passing at the instant
when each alternate tilting of the vessel, V, takes place is registered by means of
ordinary meter counting wheels, 30. The main current to be measured and
recorded enters at, 31, and passes off at, 32. A shunt, 33, leads a part of the
current to a polarised relay, 34, and thence to the casing, V, Another part of the
current passes by a wire, 35, to a system of resistances, 36, on the top of which
rests one of a connected pair of wheels, 37, the other of these wheels resting on a
straight bar, 38, through which and the wire, 39, that part of the current proceeds.
The current flowing through the relay, 34, and parts connected therewith may be
kept.constant however much the main current may vary above a certain minimum.
When the current through the relay, 34, is right its armature is repelled against a
tongue, 40, and admits through the resistance coil, 41, just sufficient current to
enable the solenoid, 42, acting on the electro-magnet, 43, to balance the weight, 44.
Should the current through the relay, 34, increase, the armature is further repelled
so as to make contact with the point, 45, and thereby cut out or short-circuit the
resistance, 41. Sufficient current then passes to the solenoid, 42, and electro-
magnet, 43, to pull up the weight, 44, and move the wheels, 37, until these have
sufficiently lessened the resistance through the part, 36, to render the current
through the relay, 34, what it was before The electro-magnet, 43, has fine
insulated wire coiled upon it in disk-like layers separated by thin disks of suitable
material, and the insulating material is removed from parts of the external convo-
lutions so that contacts may be formed with small rollers, 46, 47, fitted to branches
from a conductor, 48, through which a shunt current passes from the conductor, 39,
either through the resistance, 41, or through the contact point, 45, as herein before
explained. The divided currents entering the coils of the electro-magnet, 43, by
the rollers, 46, 47, pass from those coils by similar rollers, 49, into the coils of the
solenoid, 42, and from these the reunited current passes by a conductor, 50, into
the main return or negative conductor, 51. The tilting apparatus in the casing, V,
periodically moves a lever, 52, so as to form a contact between two points, 53, one
connected to the conductor, 48, which leads a current to the electro-magnet, 43, and
the other to a conductor, 54, which is a short shunt through a suitable resistance, 55,
to the main return or negative conductor, 51. Whenever a contact is thus made at
the points, 53, the solenoid, 42, ceases to sustain the weight, 44, which accordingly
runs down and at the same tinie turns a pulley, 56, having a toothed wheel fast to
it, which is then by the lever, 52, raised into gear with the first of the train of
counting wheels, 30. In this way the counting wheels are at every upward
movement of the wheel, 56, made to register a quantity corresponding to the
strength of the main current; and the total quantity registered in a given time
will when divided by the number of registering actions be the nearer to a true
average of the strength of current the greater the number is of the registrations in
that time.
•
In improved apparatus comprised in my Invention for distributing the electric
currents, the details of switches are arranged so as to be less liable than those
hitherto used to be left partly open. The movable parts or handles of my
improved switches of which examples are shown on sheet, 3, of the accompanying
drawings, are arranged either to drop by their own weight or to turn over or
down by weight when arranged as levers; and in some modifications of which an
example is shown in figure, 20, contact is made by the entering of a movable
part, 60, in between a pair of tongues, 61, of spring metal, these tongues clipping
and holding the movable part, 60, sufficiently to prevent separation by the
gravitation of the movable part, the movable part, 60, however dropping clear
away from the tongues, 61, when drawn down a little by means of its handle, 62.,
In some casse the clip tongues, 61, are insulated from each other and connected to
the separate conductors of the main or branch circuit, and the circuit is completed
by the insertion, of the movable piece of metal, 60, between the tongues. In other
cases both of the clip tongues are connected to one conductor and the other
conductor is connected to the "movable part of the switch so that when this is

page_text: turned or raised to engage with the clip tongues the current passes through the
clip tongues and onward through the movable part of the switch. Instead of the
clip tongues being the stationary part they may be on a movable piece, 63, as
shown in figure, 21, being moved up or turned into a position to embrace or clip a
stationary piece when making contact. In this example one conductor is an
insulated wire, 64, passing through a metal pipe, 65, which forms the other
conductor; but at one part the pipe, 65, is connected by a piece, 66, of ivory or
other nonconductor to a lower part, and the movable clip piece, 63, 61, forms a
conducting connection when raised but breaks the circuit when it is lowered In
the example shown in figure, 22, a tumbling lever, 67, of metal forms a conducting
connection between a pair of spring clips, 61, when in one position, but leaves the
circuit open when it is in its other position indicated by dotted lines. In the
example shown in figure, 23, a similar tumbling lever, 67, is used for making a
conducting connection between spring clips, 61. This example also comprises a
convenient arrangement for inserting a safety link of easily fusible metal in a
circuit, a short space being as it were cut out of the main copper conductor and
the ends shaped as clips to hold the fusible link, whilst a small glass tube is
arranged to cover the link and can be moved up when the link requires renewal.
In the example shown in figure, 24, the current when unbroken has to pass through
a lever, 69, and a metal spring-bladed piece, 70, the elasticity of the blades
retaining the lever when turned up. The arrangement shown in figure, 25, is
suitable where the switch is placed in an elevated position, and can be adjusted by
a cord, 71. The connection is formed by a tumbling metal lever, 67, when turned
down between a pair of spring clips, 61, in which position, indicated by dotted
lines, the lever, 67, balances a weighted handle, 72, fixed to the bottom of the
cord, 71. When the cord, 71, is drawn down it turns up the heavy end of the
lever, 67, against a stop into a position in which the weighted handle, 72, balances
it, but when this handle is lifted up the lever 67, turns down into its connecting
position.
When a main conductor has connected to it several branches such for, example
as those for a number of electric lights, each branch having a separate switch for
putting on or turning off the current, it is often desirable to turn off all the
branches by means of a single switch fitted to the main conductor and to be able
to turn on the main conductor again without turning on all the branches, so that
each of the lights or separate sets of the lights may be turned on separately and
only as required although all have been extinguished by shifting the main switch
only. To meet this requirement each branch switch is fitted with a weight or
spring which tends to open it, and an electro-magnet actuated by the current is
arranged to hold it when moved into the closed position. When the current is
turned off at the main conductor the several electro-magnets of the branch switches
loose their hold and the switches are opened by their springs or weights; but when
the main conductor is turned on again the branch switches remain open, each
until it is moved by hand into the closed position prior to which the electro-magnet
has no action on it.
Having thus particulary described my said Invention and the manner of
performing the same I have to state that what I believe to be novel and original
and claim as my Invention is :—
1. The constructing of dynamo-electric machines substantially as hereinbefore
described with reference to figures 1 to 8 of the accompanying drawings,
2. The application of copper pieces such as are shown in figure, 5, of the
accompanying drawings in the construction of rotating armatures of dynamo-
electric machines.
3. The constructing of dynamo-electric machines substantially as hereinbefore
described with reference to figures 9 to 12 of the accompanying drawings.
4. The constructing of rotating armatures for dynamo-electric machines sub- E
stantially as herein before described with reference to figure, 9, or as described with
El C

page_text: reference to figure, 11, or as described with reference to figures 12 and 13, of the
accompanying drawings.
5. The constructing of stationary electro magnets to act inside of rotating
armatures substantially as hereinbefore described with reference to figures, 9,
and 10, or as described with reference to figure, 14, of the accompanying drawings.
6. The method of causing alternate-current dynamo-electric machines to yield
continuous currents by employing alternate currents to excite the field magnets as
herein before described.
7. The application to a dynamo-electric machine of a device operated by a speed
governor or otherwise for automatically throwing it out of circuit when it ceases
to be driven or when the resistance gets above or below certain strengths as
hereinbefore described.
8. The measuring or indicating of the strength of an electric current by means
of apparatus substantially such as is herein before described with reference to
figure, 15, of the accompanying drawings.
9. The arrangement of parts for adapting current measuring or indicating
apparatus for different strengths hereinbefore described with reference to figure, 16,
of the accompanying drawings.
10. The combination of parts hereinbefore described with reference to figures, 17
and 18, of the accompanying drawings the said parts being arranged and operating
substantially as and for the purposes set forth.
11. The combination of parts constituting an electric-current meter or recorder
hereinbefore described with reference to figure, 19, of the accompanying drawings
the said parts being arranged and operating substantially as set forth.
12. The improved arrangements of switches for controlling the distribution of
electric currents, the movable parts of such switches being arranged so as when
disengaged to be kept so by their own weight substantially as hereinbefore
described with reference to figures 20 to 25 of the accompanying drawings.
13. The arrangement of the switch details of a main conductor with connected
branches, wherein the branch switches are held engaged by electro-magnets excited
by the currents and become disengaged when the main switch is disengaged and
remain so when the main switch is again engaged until each is engaged by hand
as required-as herein before described.
In Witness whereof, I, the said John Macintosh Mackay Munro, have hereunto
set my hand and seal this eleventh day of January in the year of our Lord
One thousand eight hundred and eighty-three.