IMPROVE- MENTS IN ELECTRICAL METERS WHICH IMPROVEMENTS ARE ALSO PARTLY APPLICABLE TO MOTORS TO BE EMPLOYED FOR OTHER PURPOSES
Year: 1883

page_text: LETTERS PATENT to Thomas John Handford of 42 Southampton Buildings
"
56
in the County of Middlesex Patent Agent for an Invention of IMPROVE-
MENTS IN ELECTRICAL METERS WHICH IMPROVEMENTS ARE ALSO PARTLY
APPLICABLE TO MOTORS TO BE EMPLOYED FOR OTHER PURPOSES communi-
cated to him from abroad by Thomas Alva Edison of Menlo Park in the
State of New Jersey United States of America
PROVISIONAL SPECIFICATION left by the said Thomas John Handford
at the Office of the Commissioners of Patents on the 30th May 1883.
THOMAS JOHN HANDFORD of 42 Southampton Buildings in the County of
Middlesex Patent Agent "IMPROVEMENTS IN ELECTRICAL METERS, WHICH
IMPROVEMENTS ARE ALSO PARTLY APPLICABLE TO MOTORS TO BE EMPLOYED FOR
OTHER PURPOSES," a communication to me from abroad by Thomas Alva Edison
of Menlo Park in the State of New Jersey, United States of America
This Invention has for its object principally to produce a cheap and reliable
meter for measuring automatically the electric current or energy consumed in a
system for the general distribution of electricity for light, heat, and power; and
incidentally to produce an electro-dynamic motor, suitable for this purpose, which
motor may however be put to other uses.
The ordinary electro-dynamic motors provided with commutators, when used as
the operative, or controlling elements of electrical meters, are subject to the
objection that the multiple contacts of the commutators cannot be made without
considerable indefinite or variable friction, which increases the liability to indicate
or register incorrectly, the wear upon the parts is great and there is difficulty
experienced in attaining sufficiently low resistance
These objections and difficulties are overcome by the present Invention, by the
use of a peculiar electro-dynamic motor, which is a non-commutator, or unipolar
machine, or " mono-electro-dynamic motor" its inductive or rotating portion being
a straight or one part conductor, through which the current passes in one direction
only. This peculiar motor is arranged to operate or control the operation of au
D

page_text: indicating or registering mechanism, and it is provided with devices for causing it
to perform a definite amount of work, in order to reduce to the minimum the
importance of the indefinite or variable friction as a factor in the work of
the motor.
By the use of the mono-electro-dynamic motor, it is feasible to convey powerful
current through the apparatus, without loss by the resistance at solid metallic or
multiple contacts; slow movements or rotations can be obtained with powerful
currents; and at the same time these results can be attained with exceedingly
small indefinite or variable friction.
In carrying out the Invention the mono-electro-dynamic motor is composed of a
cylinder, preferably of copper, which is closed at one end and open at the other,
and is mounted upon one end or pole of an electro-magnet, which rises vertically
from a suitable base. The cylinder is provided with a pivot or spindle which
passes through the closed end of the cylinder and has its pointed end resting in a
depression in the end of the magnet pole. This depression is filled with mercury
which surrounds the end of the spindle, and makes good electrical contact
between the parts, enabling the carrying of a powerful current without heating.
The spindle is constructed of a metal which will not amalgamate with the
mercury, platinum or platinum-iridium alloy being preferably used.
The other pole of the magnet made in one or more parts, surrounds the cylinder
and is supported from and connected with the base by one or more legs. The
limbs of the magnet are provided with a suitable winding.
The lower edge of the cylinder has fans or paddles of platinum or other suitable
metal or alloy projecting therefrom into a mercury trough. The paddles move in
the mercury, the resistance of which gives the motor a definite loading to overcome,
or work to perform, and the mercury also serves to maintain electrical connection
with the rotating cylinder. The mercury trough is provided with stationary wings
or blades to prevent the movement of the mercury in a body.
Current being passed through the winding of the magnet, and through the
cylinder, such cylinder will revolve, the speed being directly proportionate to the
current, and this motion may be used to advantage to operate or control suitable
indicating or registering mechanism for measuring the electrical current or energy
consumed in a circuit. The indicating or registering mechanism may be connected
mechanically with the rotating cylinder, preferably by a worm and worm wheel,
and be operated directly by such cylinder, or it may be operated by an electro-
magnet in a local circuit closed or opened at intervals by the movement of the
cylinder. In this latter case a spring may be used which is normally prevented
from striking the spindle of the rotating cylinder by means of an insulating pin,
but once in every revolution is struck by a metal pin on the spindle, thus closing
circuit through the magnet and giving one impulse to the indicating or registering
apparatus.
For use in a multiple arc system of electrical distribution, the house circuit,
between the street mains and the translating devices, is opened, and connection
made with the base of the motor and the mercury trough bringing the cylinder
directly into the house or translation circuit, although it is evident that it may be
arranged in a shunt around a definite resistance in such circuit
The lamps, motors, or other translating devices being in multiple arc, variations
in the number of such devices produce direct variations in the current or energy
consumed in the circuit, and in the speed of the motor. The field or magnet
winding of the motor is preferably arranged in a multiple aro circuit from the
house or translation circuit in which field circuit may be an additional resistance
or not as desired. This makes the field a constant one, while all the variations are
produced in the revolving one-part or straight inductive portion of the machine.
A permanent steel magnet can be used to produce the constant field, but it is
preferred to employ the electro-magnet as already described.
In order to prevent loss of energy by a flow of current through the field circuit
of the motor when there is no translating device in circuit, means are provided

page_text: for opening the field circuit at such times and for closing such circuit when the
first translating device is placed in circuit. This is accomplished by using an
electro magnet located in the house circuit, or in a shunt therefrom between the
translating devices, and the mains which magnet controls a lever, by the movement
of which the field circuit of the motor is opened and closed.
In order that the rotating shell may so perform its work that the speed of
rotation will be directly proportionate to the current, the paddles upon the cylinder
must be correctly proportioned, and arranged in a proper manner.
Since the meter may be made of quite large size, and when so made will have a
large initial friction, it is preferred for large size meters, to make the cylinder
paddles loose, and provide means for varying their dip in the mercury in proportion
to the speed, in order to make the speed of rotation of the cylinder directly
proportionate to the current For this purpose the paddles may be arranged to be
raised and lowered or to be otherwise moved to vary their dip or bearing in the
mercury of the trough by means of a centrifugal governor.
It is not essential that the shell forming the inductive portion of the motor
should revolve, since it may be held stationary and the magnetic core (whether a
permanent or electro magnet) be arranged for revolution
It is also not essential to have a magnetic field for the motor, since the cylinder
will rotate if a helix alone is used forming an electric field, but the use of a
magnetic field is preferred, since less current is required to perform the work.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas John Handford in the Great Seal Patent Office on the
30th November 1883.
THOMAS JOHN HANDFORD of 42 Southampton Buildings in the County of
Middlesex Patent Agent
"IMPROVEMENTS IN ELECTRICAL METERS WHICH
IMPROVEMENTS ARE ALSO PARTLY APPLICABLE TO MOTORS TO BE EMPLOYED FOR
OTHER PURPOSES a communication to me from abroad by Thomas Alva Edison
of Menlo Park in the State of New Jersey, United States of America
”
The said Invention relating to improvements in electrical meters has reference
to the use in combination with indicating or registering apparatus of what is herein
designated a mono-electro-dynamic motor for operating or controlling the operation
of such indicating or registering apparatus, which motor is a non-commutator or
uni-polar machine, its inductive portion being a straight or one part conductor,
through which the current passes in one direction only. This one part or straight
inductive portion is in the translation circuit, or in a shunt therefrom around a
definite resistance in the translation circuit, the electrical energy consumed in which
circuit is to be measured, whilst the field coils or helices of the machine are in a
multiple are circuit. Means located in the translation circuit are employed for
opening the circuit of such field coils or helices when the last translating device is
removed from circuit and for closing the circuit of such field coils or helices when
the first translating device is placed in circuit. The motor is provided with
devices for imparting to it a definite loading in combination with which may
be used means for varying such load to compensate for variations in proportionate
friction, this part of the invention being also applicable to motors to be employed
for other purposes.
And in order that the said Invention may be perfectly understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the accompanying sheets of drawings the same letters of
reference indicating corresponding parts in all the figures.
Figure 1 (Sheet 1) of the accompanying drawings is a sectional elevation of the
mono-electro-dynamic motor used as a meter with an elevation of an indicating or
registering mechanism and a diagram of connections.
Figure 2 is a plan of the revolving cylinder showing means for completing the
circuit of the registering mechanism.
Figure 3 a sectional elevation of a modification shewing the registering mechanism
operated directly by the revolving cylinder.
Figure 4 an elevation of the cylinder showing means for varying the loading of
the motor to compensate for variations in proportionate friction.
Figure 5 (sheet 2) a vertical section of a modification wherein the magnetic core
revolves and the non-magnetic cylinder remains stationary and,
Figure 6 a vertical section of a modified form of the motor wherein no magnetic
parts are used.
The mono-electro-dynamic motor is composed of an iron base A which forms the
back of the field electro-magnet of the machine, one pole of which is the upper
end S of the central core B, while the other pole is formed by the ring, or a number
of separate pole pieces N, supported on cores C rising from A and surrounding the
pole S.
The cores B, C, are provided with wire bobbins B³, C³,

page_text: In the magnetic field between S and N is located the revolving one part or
straight inductive portion of the machine. This is preferably a cylinder D which
may be of copper, and which is supported upon S by a central pivoting spindle a
resting in a depression b in the top of S. This spindle passes through a guiding
yoke a' and through the centre of the closed upper end of the cylinder and is
secured rigidly thereto. It is pointed and is constructed of platinum or platinum
iridium alloy, so as not to amalgamate with the mercury c with which the
depression b is partly filled The revolving pivot or spindle is located in the
translation circuit as will be presently explained, and the mercury is used to make
good and sufficient contact, in order to carry a powerful current without heating.
The lower end of the cylinder D is provided with means for maintaining contact
with the mercury d in a circular trough E. This means is preferably in the form
of fans or paddles e, which dip into the mercury, and while maintaining the circuit
complete, act to retard the movement of the motor giving it a definite loading,
or a definite amount of work to perform. The mercury trough E may be provided
with stationary blades f to prevent the rotation of the mercury in a body.
Current being passed through the bobbins B, C, and through the cylinder D,
such cylinder will revolve the speed being directly proportionate to the current
and this motion is used to operate or control suitable indicating or registering
mechanism F, for measuring, the electrical current or energy consumed in a circuit.
In Figure 1 the connections are shown for the use of the peculiar motor as a
meter in a multiple arc system of electrical distribution.
1, 2 are the street mains, and 3, 4 a house circuit therefrom having connected
therewith in multiple arc, lamps or other translating devices L.
In the house circuit, between the street mains, and the translating devices the
line 3 is broken and is carried to the mercury trough E whence the current passes
through the mercury d to paddles e and up the one-part or straight inductive
portion of the machine formed by cylinder D, to spinde a, and then through this
spindle and the mercury c to core B; the current passes down core B to base A,
with which the other side of line 3 is connected. The motor is thus brought
directly into the translation circuit and all the current supplied to the translating
devices passes through it, but it is evident that the same result would be produced
if the motor were located in a shunt around a definite resistance in line 3.
The translating devices being in multiple arc, variations in the number of such
devices produce direct variations in the current or energy consumed in the circuit
and in the speed of the motor.
The field of the motor is in a multiple arc circuit 5, 6 from 3, 4, all the
bobbins B¹ C¹, being located in such circuit and an additional resistance R being
also preferably employed. The location of the field magnet in a separate multiple
are circuit makes the field a constant one, while all the variations are produced in
the revolving one part or straight inductive portion of the machine.
In order to prevent loss of energy by a flow of current through the field
circuit 5, 6, when there is no translating device in circuit, means is provided for
opening the circuit 5, 6 when there is no translating device in circuit and for
closing such circuit when a single translating device is placed in circuit.
For this purpose an electro-magnet G is located in line 3 or in a shunt therefrom,
between the translating devices and the street mains, and controls a lever g situate
in circuit 5, 6, and closing circuit 5, 6, at its front contact as shewn when a single
translating device is in circuit and opening such circuit at its back contact when
the last translating device is removed from circuit.
The indicating or registering mechanism F may be operated by an electro
magnet H which is placed in circuit 7, 8, between the wire 5 on one side of
resistance R to a spring h mounted on an insulating block on N, and springing
towards the spindle a of the revolving cylinder. This spring is prevented from
striking the spindle by an insulated pin on yoke a', but once in every
revolution of the cylinder it is struck by a metal pin k on the spindle a closing,

page_text: circuit through the magnet H and giving one impulse to the indicating or
registering apparatus.
In this way the indicating or registering apparatus will indicate or register the
revolutions of the cylinder.
The indicating or registering apparatus may however be operated directly by the
cylinder, through suitable gearing as shown in Figure 3 the spindle a being
provided with a worm 7 meshing with a worm wheel m forming part of the
indicator or register.
In order that the rotating shell may so perform its work that the speed of
rotation will be directly proportionate to the current, the paddles upon the cylinder
must be correctly proportioned and arranged in a proper manner.
Since the meter may be made of quite large size and when so made will have a
large initial friction it is preferred for large size meters to make the cylinder
paddles loose and provide means for varying their dip in the mercury in pro-
portion to the speed, in order to make the speed of rotation of the cylinder directly
proportionate to the current. Such a construction is shown in figure 4 wherein
the paddles e are mounted on a ring n connected with a centrifugal governor I
mounted on the spindle a.
It is not essential that the shell D should revolve, since it may be held
stationary and the magnetic core be arranged for revolution as shown in Figure 5
(sheet 2).
In that Figure the shell D is held stationary in a suitable frame (not shown)
while the core B revolves. This core is made of iron magnetized by bobbins B¹
which may be stationary or be carried by the core.
The mercury trough E is carried by and revolves with the core, although it can
be stationary and the core be provided with paddles dipping into the mercury.
The core B is mounted on a spindle p turning in mercury and may operate the
indicator or register directly as shown, or by closing at intervals a local circuit.
The cylinder D and core B are located in the line 3 of the translation circuit,
while the bobbin B¹ is in a multiple arc circuit from the translation circuit.
,
It is also not essential to have a magnetic field since the cylinder will rotate if a
helix M alone is used as shown in Figure 6, but by the use of iron less current is
required to perform the work.
In Figure 6 the cylinder D revolves upon a non-magnetic support O, such
support and the cylinder being located directly in the translation circuit 3 while
the helix M is in a multiple are circuit 5, 6, therefrom.
It is to be understood that in the arrangements shewn in Figures 5 and 6 means
are to be employed as herein before described with reference to Figure 1 for
opening the circuit of the field coils or helices when the last translating device is
removed from circuit and for closing the circuit of such field coils or helices when
the first translating device is placed in circuit.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the invention secured to me by the hereinbefore in part
recited Letters Patent is :-
First In an electrical meter the combination with indicating or registering
apparatus, of a mono-electro-dynamic motor, operating or controlling the operation
of such indicating or registering apparatus; and having its inductive portion in the
translation circuit or in a shunt therefrom around a definite resistance in the
translation circuit, the electrical energy consumed in which circuit is to be
measured, a multiple arc circuit including the field coils or helices of such motor,
and means located in the translation circuit for respectively opening and closing
the circuit of such field coils or helices when the last translating device is removed
from circuit and the first one placed in circuit, substantially as hereinbefore
described.

page_text: Second: A mono-electro-dynamic motor, in combination with means for giving
such motor a definite loading, and means for varying such load to compensate for
variations in proportionate friction, substantially as, and for the purposes, herein-
before described.
In witness whereof I the said Thomas John Handford have hereunto set my
hand and seal this twenty ninth day of November in the year of Our Lord one
thousand eight hundred and eighty three.
TH J HANDFORD (L.S.)