Improvements in Electromotors, applicable for Use as Electric Meters
Year: 1895

page_text: PROVISIONAL SPECIFICATION
Improvements in Electromotors, applicable for Use as Electric
Meters
I HENRY AUGUSTUS ROWLAND of 915 Cathedral Street Baltimore Maryland
United States of America Professor of Physics of Johns Hopkins University do
hereby declare the nature of this invention to be as follows
-
My invention relates to electric meters, and its object is to provide a simple and
cheap apparatus for measuring the time integral of an electric curient, which
apparatus is ordinarily called "a current meter
This inventior belongs to that class of meters, known as motor meters, being in
general a motor actuated by the current to be measured and working against a
resistance proportional to the speed
One of the hereindescribed improvements in such meters consists in supporting
the coils of the meter by the same non-magnetic conductor which produces the
damping effect by its revolution in the magnetic field, moreover this combination
of a motor and conductor is not only eminently adapted for measuring an electric
current, but it also has a remarkable degree of uniformity of speed, and is suitable
for use wherever the said uniformity of speed is desirable, as for instance, in clocks
for driving astronomical telescopes, chronographs and for a great variety of other
uses which it will not be necessary to enumerate
The invention also consists in placing a shunt across the terminals of the motor,
or between the commutator segments, for the purpose of reducing sparking, of
regulating and changing the constant of the meter, and for protecting it in case the
brushes become displaced or worn
The invention also includes introducing a device for correcting the motor for
variations of the temperature
It is further proposed to immerse the commutator in oil for the purpose of washing
away the dirt, of keeping the contact good, and of lubricating the commutator to
reduce friction
While the broad idea of my invention is capable of a great variety of modifications
it will be described with reference to two generic types, which will be understood
by reference to the accompanying drawings in which the same parts are indicated
by the same letters throughout the several views
Fig 1 represents a disc-shaped plate made of non-magnetic conducting material
which disc carries the wires for conveying the current to be measured, and rotates in
a magnetic field
Fig 2 represents a section along the line 2-2 of Fig 1, and looking down
Fig 3 represents a modified form of disc in which the wires are let into the
conducting plate or disc
Fig 4 represents a section along the line 4-4 of Fig 3
Fig 5 represents a side elevation, partly in section in which the disc shown in
Figs 1 to 4 is replaced by an inverted cup-shaped vessel made of non-magnetic
conducting material, on the surface of which the coils of wire carrying the current
to be measured are mounted

page_text: Fig
Fig
6 represents a section along the line 6-6 of Fig 5, and looking down
7 represents a vertical section along, the line 7-7 of Fig 6
Fig 8 represents In side elevation, on an enlarged scale the device for
compensating for changes of temperature
Fig 9cpieschts a plan view of the device shewn in Fig 8
Fig 10 represents an end view of the resistance wires alapted to be thrown in
multiple circuit as the temperature ise, and
Fig 11 represent
invention
a detal view of a ball-bearing adapted for use
in my
A repie ents a magnet, preferably permanent one, and having enlarged pole
pieces A on one side of the revolving surface On the other side of the revolving
surface and in close proximity thereto is a soft non plate A2, as shown in Figs I
and 2, or a soft non cylinder A³, as shewn in Fig 7
Refering especially to Figs 1 and 2, the disc B, made of copper or othei
suitable non-magnetic conducting material is mounted on the shaft b and carries a
plurality of coils, preferably three in number, Bo, which are wound as shewn in
Fig 2 and are connected to the commutator C by conductors connected midway
between the said coils
In order to reduce the surface of the said coils exposed to the air and to enable
the said disc with the coils mounted thereon to fit snugly between the parts A
and A2 which excite the magnetic field, the wies are flattened as at 60 but the said
disc may be provided with chambers or pockets as shewn in Figs 3 and 4, wherein
B represents the dic and the pockets which may be of any desired form or
shape and in which the wires may be laid so as not to project above the surface of
the disc, while grooves and 16 may be provided to receive the wires connecting
the adjacent coils, and also connecting the conductors between the said coils to the
commutator A cover may also be added to enclose the coils if so desired
The lower end of the shaft b, which supports the armature may be supported
upon anti-fiction bearings of any type, but preferably upon the ball-bearing shewn
in Figs 1 and 11, in which B7 represents a case carried on the upper end of the
adjusting sciew 67, in which case are mounted pluiality of balls 68 free to roll
around in said case
On these balls the rounded end 69 of the shaft is upported
This or any other suitable ball-beating or anti-friction being may be used in
the instrument
The commutator 15 preferably immersed in oil in a cup D, as shewn in
Figs 1 and 2
E and E' repre ent the bushes which connect the commutator with the wires F
and F connected to the source of electricity
Between these wires
and Fa hxed resistance R° is inserted, which
resistance should be regulated by the instrument maker to suit the constant of
the meter
A second adjustable resistance R is also placed between the wires, which
resistance automatically regulates the meter for variations in temperature as
illustrated in Figs 8 to 10
In these figures one of the wires, and H¹, is connected to a spiral spring R
which is preferably made of zinc and iron, which spring carries at its free end ra
conducting strip r³ transversely disposed and adapted to pick up one or more of the
free ends of the wires 2, which wires project through grooves 70 in the non-
conducting support R2, which grooves are arranged in a series of steps as shewn in
Fig 10, and the said strip is adapted to make connection through one, two or
more of these wires, the other ends of which are connected to the opposite wire F
Thus when the temperature is increased the spring R' will expand, throwing the
resistance wires in multiple and directing a laiger proportion of the current
through the shunt than when the temperature is low
Since the meter will tend to go faster when the temperature is higher, due to the
lower conductivity of the conducting revolving mass, and the consequent diminished

page_text: damping effect, the effect of lessening the resistance in the shunt will be to slow
down the meter, and thus an exceedingly nice adjustment or regulation may be
obtained
The number of revolutions of the meter are indicated by the registering
apparatus H, which may be of any well-known type
In the form of device shewn in Fig. 5 tỷ 7, the Hat disc B is replaced by an
inverted cup B' of copper or like conducting non-magnetic material, on the surface
of which the coils B° are wound which coils are connected to each other and to the
commutator as has already been described with reference to Figs 1 and 2
Inside of this inverted cup is oft iron cylinder A³ which combines with the
pole pieces A' to form a magnetic field, in which the cup is revolved
The connections of the various parts and the operation of the meter is precisely
the same in either case
The various puts of the fi imework u ed in supporting or journalling the fixed
or evoluble part, are indicated by the letter q, and are made of bras, or any other
suitable non-magnetic material
but
Three coils of we are preferably used, as this is the least number that will, with
proper shaped pole peces, cause a uniform torque with no dead point, any
number greater than three may be used if desired
Also the number of magnetic poles might be increased at will
Moreover other modes of winding the we might be adopted the idea always
being to use the metal conducting body as a support for the coils as well as to
produce the resistance to the motion by the movement of the said conducting body
in the magnetic held
While the commutator should preferably be immersed in oil, glycerine, or other
non-conducting liquids, the commutator may be run diy, if desired, or any suitable
mechanical device for supplying oil may be used
While I have shewn a rotating disc, and an inverted cup, any surface of
revolution may be provided with an arrangement of co ls, and the wires may be led
therefrom to the commutator in any way that may be desired A long as the
amature coils will not remain in position when the damping conducting body is
removed, so far the spirit of my invention extends By thus giving to the damping
conductor the additional function of supporting the armature coils, the construction
1 very much simplified
There is also another advantage gained by making the conducting body and the
coils revolve in the same magnetic field, and that is that the variations of the speed
due to change of magnetism are orly half as great as if the motor was outside that
field
By making the armature without iron, a meter and also a motor are obtained,
In fact,
having many desirable properties not possessed by those containing iron
a meter with non in the armature is so affected by hysteresi that it is not reliable,
and, indeed, is not a practical instrument
The revolving surface her eindescribed, taken in combination with the permanent
magnets, constitutes a motor having a most remarkably uniform speed, and hence
the said motor is eminently adapted for all purposes where a constant speed is
desired, such as in astronomical clocks or other like apparatus, as well as in electric
meters
Dated the 6th den of M. 1905
PHILIP M JUSTICE,
London, Chartered Patent Agent,
For the Applicant

page_text: Improvements in Electromotors, applicable for Use as Electric
Meters
I, HENRY AUGUSTUS ROWLAND, of 915 Cathedral Street, Baltimore, Maryland,
United States of America, Professor of Physics of Johns Hopkins University, do
hereby declare the nature of this invention and in what manner the same is to bu
perforined, to be particularly described and ascertained in and by the following
statement
-
My invention relates to electric meters, and its object is to provide a simple and
cheap apparatus for measuring the time integral of an electric current, which
apparatus is ordinarily called "a current-meter
being
This invention belongs to that class of meters known as
<< motor-meters
in general a motor actuated by the current to be measured and working against a
resistance proportional to the speed
One of the hereindescribed improvements in such meteis consists in supporting
the coils of the meter by the same non magnetic conductor which produces the
damping effect by its revolution in the magnetic field Moreover, this combination
of a motor and conductor is not only eminently adapted for measuring an electric
current, but it also has a remarkable degree of uniformity of speed, and is suitable
for use wherever the sud uniformity of speed is desiable-as, for instance, in
clocks for diving astronomical telescopes, chronographs, and for a great variety of
other uses which it will not be necessary to enumerate
The invention also consi ts in placing a shunt across the terminals of the motor
or between the commutator segments for the purpose of reducing sparking, of
regulating and changing the constant of the meter, and for protecting it in case
the brushes become displaced or worn
The invention also includes introducing a device for correcting the motor for
variations of the temperature
It is further propo ed to immerse the commutator in oil for the purpose of
wa hing away the dirt, of keeping the contact good, and of lubricating the
commutator to reduce friction
While my invention is capable of a great variety of modifications it will be
described with reference to two special types, which will be understood by reference
to the drawings filed with my Provisional Specification, in which the same parts
are indicated by the same letters throughout the several views
DESCRIPTION OF THE DRAWINGS
Figuerepie ents an apparatus having a disk-shaped plate made of non
magnetic conducting material, which disk carries the wires for conveying the
curient to be measured and rotates in a magnetic field
Fig 2 represents a section along the line 2-2 of Fig 1 and looking down
Fig 3 represents a modified form of dish in which the wires are let into the
conducting plate or disk
Fig 4 represents a section along the line 4-4 of Fig 3
Fig 5 represents a side elevation. partly in section, in which the disk shown in

page_text: Fig
Fig 10 represents an end view of the resistance-wires adapted to be thrown in
multiple cucut as the temperature lises, and
represents a plan view of the device shown in Fig 8
Fig 11 represents a detail view of a ball-bearing adapted for use in my
invention
A represents a magnet, preferably a permanent one, and having enlarged pole-
pieces A' on one side of the revolving surface On the other side of the revolving
surface and in close proximity thereto is a soft-11 on plate A2, as shown in Fig. 1
and 2, or a soft-iron cylinder A³, as shown in Fig 7
Referring especially to Figs 1 and 2, the disk B, made of copper or other
suitable non-magnetic conducting material, is mounted on the shaft b and carries
plurality of coils, preferably three in number, Bº, which are wound as shown in
Fig 2 and are connected to the commutator C by conductors b', connected midway
between the said coils In order to reduce the surface of the said coils exposed to
the air and to enable the said disk, with the coils mounted thereon, to fit snugly
between the parts A¹ and A³, which excite the magnetic field, the wires are
flattened, as at 6º, but the said disk may be provided with chambers or pockets,
as shown in Figs 3 and 4, wherein B 1epresents the disk and b the pockets, which
may be of any desired form oi shape and in which the wires may be laid so as not
to project above the surface of the disk, while grooves and may be provided
receive the wires connecting the conductors between the said coils to the
commutator A cover may also be added to inclose the coils if so desired
to
The lower end of the shaft b, which supports the armature, may be supported
upon antifriction-bearings of any type, but preferably upon the ball bearing
shown in Fig 11 in which B' represents a case carried on the upper end of the
adjusting-screw, in which case are mounted a plurality of bilis 68, free to
roll around in said case On these balls the rounded end 6 of the shaft b is
supported This or any other suitable ball-bearing or antifriction-bearing may be
used in the instrument
The commutator C is preferably immersed in oil in a cup D, as shown in Figs 1
and 2
E and E represent the brushes which connect the commutator with the wires
and F', connected to the source of electricity Between these wires F and F' a
fixed resistance R is inserted, which resistance should be regulated by the instru-
ment-maker to suit the constant of the meter A second adjustable resistance R°
is also placed between the wires, which resistance automatically regulates the
meter for variations in temperature, as illustrated in Figs 8 to 10 In these figures
one of the wires F and is connected to a spiral spring R', which is preferably
made of zinc and non, which spring carries at its free end a conducting-strip,
transversely disposed and adapted to pick up one or more of the free ends of the
wires, which wires project through grooves 70 in the non-conducting support R³,
which grooves are arranged in a series of steps, as shown in Fig 10, and the said
strip is adapted to make connection through one, two, or more of these wires,
the other ends of which are connected to the opposite wire Fi Thus when the
temperature is increased the spring R' will expand, throwing the resistance-wires r²
in multiple and diecting a larger proportion of the current through the shunt than
when the temperature is low
Since the meter will tend to go faster when the temperature is higher, due to
the lower conductivity of the conducting revolving mass and the consequent
diminished damping effect, the effect of lessening the resistance in the shunt will
be to slow down the meter, and thus an exceedingly nice adjustment or regulation
may be obtained
The number of revolutions of the meter is indicated by the registering
apparatus H, which may be of any well-known type
In the form of device shown in Figs to 7 the flat disk B is replaced by an
inverted cup B, of copper or like conducting non-magnetic material, on the surface
of which the coils B° are wound, which coils are connected to each other and to

page_text: the commutator, as has already been describel with reference to Figs 1 and 2
Inside of this inverted cup is a soft iron cylinder A³, which combines with the
pole-pieces A to form a magnetic field, in which the cup is revolved
connections of the various parts and the optation of the meter are precisely
the same in either case
The
The various parts of the framework used in supporting or journaling the fixed
or revoluble parts are indicated by the letter y, and are made of biass of any other
suitable non-magnetic material
Three coils of wire are preferably used, as this i the least nu nber that will
with proper shaped pole-pieces, cause a uniform torque with no dead points but
any number greater than three may be used, if desired also, the number of
magnetic pole might be increased at will Moreover, other modes of winding
the wire might be adopted, the iden always being to use the metal conducting boly
as a support for the coils as well as to produce the resistance to the motion by the
movement of the said conducting body in the magnetic field
While the commut to should piefe ably be immersed in oil, glycerine or other
non-conducting liquids the commutator may be run dry, if desired, or any suitable
mechanical device for supplying oil may be used
While I have shown a rotating disk and an inverted cup, any surface of revolution
may be provided with an air ingement of coils, and the wires may be led therefion
to the commutator in any way that may be desired By thus giving to the damping-
conductor the additional function of supporting the arm iture- oils the construction
is very much simplified I here is also another advantage gained by making the
conducting body and the coils revolve in the same magnetic held, and that is that
the vanations of the speed due to change of magnetism we only half as great as
if the amature were outside that held
By making the amature without iron a meter and also a motor are obtained
having many desirable properties not posse sed by those cont uning iron In fact,
a meter with iron in the armature is so affected by hysteresis that it is not reliable,
and indeed, is not a practical instrument
The evolving surface hereindescribed, taken in combination with the permanent
magnets, constitutes a motor having a most remarkably uniform specd, and hence
the said motor is eminently adapted for all purposes where a constant speed is
desned, such as in astronomical clocks or other like apparatus, as well as in electric
meters These and the various other advantages of the het eindescribed construction
will readily suggest themselves to any one skilled in the art
Having now particularly described and ascertained the nature of my said inven
tion, and in what mannei the same is to be performed I declare that what I
claim is
-
1 In an electic meter, the combination with an armature consisting of a mass
of conducting non magnetic metal, formed into a surface of revolution, and
supporting a plurality of coils for carrying an electric current, the said mass
serving not only as a support to the coils, but as a retarding influence due to the
currents induced therein of a cominutator connected to said coils, conducting
wires and brushes for connecting the source of electricity to said commutator,
and a shunt interposed between said conducting wires, substantially as described
2 In an electric meter, the combinatio with an armature consisting of a mass
of conducting non-magnetic metal, formed into a surface of revolution, and
supporting a plurality of coils of wire for carrying an electric curient, the said
mass serving not only as a support to the coils, but as a retarding influence due to
the curients induced therein, of a source of electricity, and conductors for
carrying the same into and out of said armature, and a shunt with means for
regulating the same inserted between said conductor, substantially as described
3 In an electric motor, the combination of a source of electricity, an armature
consisting of a disk with chambers in the face thereof, with coils of wire mounted
En said chambers, which disk is adapted to furnish a support for the sail coils and

page_text: Lo to effect the retardation of its own motion, due to the currents induced thereio,
and conductors connecting said armature with said source of electricity, substantially
19 described
4 In an electric motor, the combination of a source of electricity, an armature
consisting of a non-magnetic conducting disk with chambers in the face thereof,
with coils of wire mounted in said chambers, which disk is adapted to furnish a
support for the said coils, and to effect the retardation of its own motion, due to
the currents induced therein, conductors connecting said armature with said source
of electricity, and shunt interposed between said conductors, substantially as
described
5 In an electric meter, the combination with an armature consisting of a mass
of conducting non-magnetic metal, supporting a plurality of coils for carrying an
electric curent, the aid mass serving not only as a support to the coils, but as
retaiding influence due to the currents induced therein, of a commutator connected
to said coils, conducting wires and brushe for connecting the source of clectricity
to said commutator, and an automatically regulated shunt interposed between said
conducting wires, substantially as described
6 In an electic meter, the combinat on with an armature consisting of a mass
of conducting non-magnetic metal, supporting a plurality of coils of wire for
carrying an electric current, the said mass serving not only as a support to the
coils, but as a retarding influence due to the currents induced therein, of a source
of electricity, and conductors for carrying the same into and out of said armatures,
and a fixed shunt and an automatically adjustable shunt inserted between said
conductors, substantially as described
7 The arrangement and combination of parts herein before described and
illustrated in the accompanying diawings for winding and supporting the coils
of the armature
8 An electric meter constructed substantially as herem described and shown in
the drawings
Dated this 1et der of Fahru 1806
PHILIP M JUSTICE,
55 & 56 Chancery Lane, London, Chartered Patent Agent,
For the Applicant