Meter or Apparatus for Measuring Continuous or Alternating Electric Currents.
Year: 1888

page_text: COMPLETE SPECIFICATION.
A Meter or Apparatus for Measuring Continuous or Alternating
Electric Currents.
I, GEORGE FREDERICK REDFERN, of the firm of G. F. Redfern & Co., the General
Patent Office, No. 4, South Street, Finsbury, in the County of Middlesex, Patent
Agents do hereby declare the nature of this invention (a communication from abroad
by Lucien Brillie, of Paris, in the Republic of France) and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
This new apparatus belongs to the class of Waits-hour-meters; it is based on the
employment of the torsion electro-dynamometer and serves to measure periodically
the angle of torsion of the spring of the electro-dynamometer.
The apparatus I am about to describe is designed for measuring continuous currents,
but an arrangement which will be further described towards the end of the Specifi-
cation allows of also measuring alternating currents.
The apparatus represented in the drawings registers the sum of the products E × [
effected at equal intervals of time, 100 times per hour for example, I being the
intensity of the current which passes through the conductor in which the electric
force is expended, E the difference of potential at the ends of the conductor.
In order to enable the invention to be fully understood
reference to the accompanying drawings, in which,
"
will describe the same by
Figure 1 shews the arrangement of the apparatus as a whole and the direction of
the current of derivation which works it.
Figure 2 is a plan of the apparatus. To render this Figure more clear the wires
which are represented in Figure 1 are not shewn.
Figure 3 is a sectional elevation taken on the line X, X of Figure 2.
Figure 4 is a sectional elevation on the line X, Y of Figure 2.
Figure 5 is a sectional elevation on the line Z, Z, of Figure 2.
Figure 6 is a sectional elevation on the line y, y of Figure 2. The parts for
moderating the speed are not shewn in this figure.
Figure 7 is an end view of the clock movement taken on the line 2 of
Figure 2.

page_text: '
Figure 8 is a vertical section taken on the line m', m' of Figure 2.
Figure 9 is an elevation of the speed regulator taken on the line n', n' of
Figure 2.
Figure 10 is a diagram shewing the angles of the turning movement of the
shaft 11.
Figure 11, I, II, III, IV and V are diagrams shewing the positions consecutively
taken by the contact pieces 6, 61.
The apparatus is constructed of five principal parts as shewn in Figures 1
and 2.
1. A torsion electro-dynamometer A which values the product E × I.
2. An electro-motor B which at each measuring operation winds up the clock-
work D slowly distends the spring of the electro-dynamometer until its movable
bobbin becomes displaced under its action and finally returns it to its original
position.
3. A governor or regulator which regulates the various movements.
4. A clock movement D determining the interval of 36 seconds between each
measuring operation.
5. A register (Num. Figures 1 and 2) of the sum of the products E × I by
advancing at each measuring operation a proportionate degree to the angle of torsion
of the spring of the electro-dynamometer.
I will describe in detail each one of these parts in order that the working of the
apparatus may be fully understood.
Electro-dynamometer. The electro-dynamometer A, Figures 2, 3 and 4 is con-
structed (similarly to other known apparatus of this class) of two fixed coils 1, 1' of
thick conductors or of strips of copper traversed one after another by the current (the
intensity of which is of I) and of a moveable hobbin 3 wound with fine wire
traversed at the moment of each measuring operation by a proportional current at E.
The axis of the bobbin 3 rests on a knife edge 4 and a point 5 which allows of
the bobbin being balanced on the horizontal axis the displacement is sufficient to
break contact at 6, 61, it is limited by two stops 2, 21, placed at each side so as to
ensure the same position at each measuring operation.
To the end of the bobbin axis is fixed one end of a torsion spring 7 the other
end of which is fixed to a horizontal shaft 8 which is driven by the electro
motor B.
Electro motor. The electro-motor B (figures 2, 3, 5 and 6) is constructed of an
electro-magnet. 9, 9, acting simultaneously on three armatures.
1. The principal armature 10 (figures 2 and 5) fixed on the shaft 11 and placed
between the curved pole pieces 12 and 12, which causes it to turn through a
sufficiently large angle.
2. The oscillating bar 13 (figures 2, 3, and 6) moveable on the shaft 11 and the
inovement of which, limited by the pin 14 fixed in the frame of the motor, is
utilised for periodically winding up the clock movement and putting it in operation.
3. An iron tappet 13 (figures 2, 3, and 5) placed under the pole piece 211 and
fixed on the shaft 16 moves the part 6 of the contact 6, 6¹ of the electro-dynamo-
meter A (see figures 2 and 4).
The shaft 11 of the principal armature 10 transmits its movement (which it receives
from this latter) by means of a toothed sector 17 and a pinion 18 to the shaft S
which actuates the governor (which regulates the speed of torsion of the spring 7
above mentioned.
The shaft 11 is brought back to its position of rest by the spring 19 (figure 5).
The stop 20 (figure 6) which is keyed on the shaft then comes under the screw 21
which is placed on the arm 22 fixed to the oscillating bar 13 which can only be
lowered slowly by causing the shafts 11 to turn while it can rise again quickly
under the action of the spring 23 (figure 6).
Governor. The governor C (figures 2, 8, and 9) is intended to render as constant
as possible the speed of torsion of the spring 7.
The axis of the winch 24 is a continuation of the axis 8 (figures 2 and 9)

page_text: on which is fixed the toothed wheel 25, which turns the winch 24 by means of
a pinion 26 and toothed wheel 27 which. an
are mounted in a frame 28 moveable on
the shaft 8.
This frame is kept in its normal position by means of a spring 29 acting by means
of the lever 30 on pins 31 and 31 fixed to the frame. The tension of the said
spring 29 corresponds with the part which should act on the winch 24 to give it its
normal speed.
The frame 28 in inclining during rotation, by means of the brake blocks 32 and 32¹,
acts as a brake on the disc 33 driven by means of the pinion 34 through the wheel 25
and the excess of force of the shaft 8 is absorbed by this friction.
This governor regulates effectively the speed of torsion of the spring 7.
Clockwork. The clockwork. D (figures 2, 3 and 7) operates by means of satellite
wheels; normally the wheel 35 is held fixed by the ratchet wheel 36 (fig. 2, 3 and 6)
and the fixed pawl 37. The frame 38, which supports the satellite wheels 39 and 40
(figures 3 and 7) under the action of the spring 41 rises in proportion as the escape
wheel 42 turns under its action.
By the expression satellite wheels I mean toothed wheels which, like the wheels 39
and 40, and also like the wheels 26 and 27 of the governor above described, are
mounted in movable frames so as to be able to engage with corresponding toothed
wheels placed on another shaft in such a manner as to roll, so to speak, on the
periphery of these latter wheels.
The solid contact 43 of the frame 38 at a certain moment makes contact with 43¹
(figure 7).
The oscillating bar 13 (figures 6 and 3) attracted by the electro-magnet 9, 9, as
will be hereinafter described immediately causes the ratchet wheel 36 to advance one
tooth by means of a pawl 44 which is fixed on the said oscillating bar; the frame 38
then falls in so doing immediately breaking the contact 43, 431.
I would here remark that while the oscillating bar is turning, the screw 21 hears on
the stop 20 and causes the shaft 11 to turn through a small angle which I hereafter
designate by y.
From the preceding description it will be seen that the intermittent movement of
the wheel 35 transmits a continuous movement to the escape wheel 42 whilst giving
to the frame 38 an alternating movement.
The interval of time between two contacts is constant and easy to regulate by means
of a pendulum 45 (figure 3).
An arrangement for automatically starting the clockwork movement will be herein-
after desscribed.
Register or Counter. As will be seen further on the total angle through which the
shaft 11 turns is composed of two angles y and a which are added to each other and the
sum of which is the measure of the total movement which the shaft makes ; the angle y
is a constant angle whilst the angle a is proportional to the power exerted by the
electro-dynamometer and consequently to the product Ex I. It is therefore only the
latter angle a which. should be registered by the counter (Num. Figure 1) at the
moment of each measuring operation.
The counter, properly so called, is of any suitable known construction; in the
drawings (Figure 2) I have shown a counter having 5 numeral wheels.
The shaft 47 is driven by means of brake or clutch mechanism which is very sensitive
and which transmits all the movements with exactitude. On the shaft 47 is fixed a
cylinder 48 (see Figures 2 and 5) provided with two grooves in which are placed
triangular pieces of metal wire 49 and 491 each bent at an angle 50 and 50¹ the
angular parts being rendered flexible by a file stroke. The lower end 51 of the
piece 49¹ is fixed whilst the end 52 of the piece 49 enters a small slot 54 formed in the
end of an arm 53 hinged to the arm 56 fixed on the shaft 11.
From this construction it will be seen that any pressure exerted from right to left
on the end 52 of the piece 49 tends to close the angle 50 so as to grip the cylinder 48
and cause it to turn and with it the shaft 47 of the counter with its numeral
wheels.

page_text: I on the contrary the end 52 is drawn to the right the angle 50 opens whilst the
angle 50¹ closes and grips the cylinder 48 which remains fixed."
Having now described the various parts of my apparatus I will describe the manner
in which it operates.
WORKING OF THE APPARATUS WHEN ELECTRIC FORCE IS BEING UTILIZED.
The principal current from the source of electricity enters the apparatus at M
passes through the coils 1.1' reaches the terminal P traverses the lamps 1 or other
installation where the power is utilized and returns by the terminal N to the source of
electricity S (Figure 1). The wires of the current of derivation necessary for the
working of the apparatus are attached to the terminals M. and N ; they are arranged
as shewn at Figure 1. The current of derivation coming from M is broken from
one side on the contact of the clockwork 43, 43¹ and from the other side on the
contact of the electro-dynamometer 6, 61; the contact pieces 43 and 6 both com-
municate with the terminal M. The parts 431 and 6 communicate with each other
by a wire attached at the points a and b.
At the point a is also attached one end of the wire of the electro-magnet 9 at the
point is attached one end of the wire of the bobbin 3. The other ends of the said
wires of the electro-magnet 9 and of the bobbin 3 are attached at the point c which is
connected to the terminal N.
I will describe the action of the apparatus at the moment contact is established
at 43, 43 in consequence of the clock movement being put in operation. The derived
current starting from the terminal M follows the direction indicated by the
arrows o traverses the contact 43, 43' and reaches the point a; thence a part
passes through the bobbins 9, 9 of the electro-motor and returns by the point e to the
terminal N another part passes by into the bobbin 3, and also leaves at N.
The electro-magnet at the moment that the bobbins 9, 9 are traversed by the current
becomes active and produces the following results :-
1. The tappet 15 is attracted by the pole piece 12' and closes the contact 6, 6¹, the
current then traverses the electro-magnet 9, 9 and the bobbin 3 through the route
indicated by the arrows. The parts 6, 61 of the contact pass from the position I
to the position II (see Figure 11).
2. The oscillating bar 13 and the armature 10 are both attracted and together cause
the shaft 11 to turn and with it by means of the sector 17 and the pinion 18, the
spring 7 during a certain movement the latitude of which is through an angle y
during this movement the oscillating bar 13 has wound up the clockwork by means of
the ratchet 36 and the pawl 44 (whilst lowering the frame 38) as above described, and
the contact 43, 43' has been immediately broken.
3. When once the angle y has been traversed the oscillating bar 13 remains fixed
supported on the core of the electro-magnet 9 which attracts it and holds it, whilst the
armature 10, continuing its turning moveinent between the pole pieces 12 and 12¹
continues to progressively distend the spring 7 of the electro-dynamometer by means
of the sector 17 and pinion 18. When it has thus traversed (in continuation of the
angley already described) a certain angle a the moment arrives when the force of
torsion of the spring 7 counterbalances the power exercised by the currents which are
acting in the electro-dynamometer A; at this moment the bobbin 3 is drawn along
by the spring and the contact 6, 6¹ takes the position III (figure 11) and is broken.
It is now easy to ascertain the manner in which the counter registers the angle
at the moment when the shaft 11 reaches its maximum distance of separation or
turning movement. During the first part of this movement corresponding to the
angle and necessary as will be hereafter explained for the constant winding up of
the clockwork, the counter should not register; this is effected by the slot 54 in
which slides the end 52 of the piece 49 of the frictional brake or clutch arrangement
and owing to this slot the arm 53 will only exert pressure on the piece 49 when the
said end 52 comes against the end 55 of the slot; it is thus easy to regulate by
means of a screw 57 the length of the slot in such a manner that 52 meets 55 when
"

page_text: It still remains to describe an arrangement for automatically putting in operation
the clockwork immediately the apparatus is put in communication with the source of
electricity.
The contact 43 (figures 3 and 7) is fixed to a piece of chonite 60, terminated by a
steel point and capable of oscillating slightly on the axis 61. A small spring 62 keeps
it slightly inclined in the position indicated in figure 7.
The axis 61 is carried by a piece 63 pivotting on 64 and so counterweighted as to
keep the lever 60 in a raised position.
A screw 64¹ having a hollow point placed on the arm 22 of the oscillating bar 13
is in the plane of oscillation of the piece of ebonite 60.
In ordinary working the contact 43, 431 is broken immediately the screw 64¹ passes
at the side of the steel point and none of the levers move.
But if the circuit is broken in any point, the lever 60 is drawn along by 43 under
the action of the spring 41 of the clockwork, the steel point comes into position
under the screw 64 where its further movement is arrested by a stop 69.
At the moment when the circuit is re-established, the oscillating bar 13 winds up.
the clockwork in the ordinary way at the same time that the screw 64' lowers the
steel point and causes the rod 65 to push the rod 66 having a fork 67 which raises or
puts in an inclined position the suspension rod GS of the pendulum 45.
At the moment when the contact ceases at 6, 61 at the end of the first measuring
operation, the screw 64' rises suddenly, releasing the levers which immediately retake
their position. The pendulum thus freed commences to oscillate..

page_text: I would here remark that in figure 7 in order to render the drawing more clear
I have cut short the suspension rod 68 of the pendulum; for further clearness the
various toothed wheels, satellites and others are shown by circles in full lines
surrounded by circles in dotted lines indicating the teeth.
MODIFIED ARRANGEMENTS.
1. In order to measure, with the counter above described, alternating currents,
or currents in which the difference of potential varies a great deal I could employ a
source of electricity having a continuous current for working the electro-motor.
A special circuit can lead this current to a series of counters, depending from a
central station for example. The arrangement of the wires in this case is represented
by the Figure412, the points m and n being placed in derivation over this special
circuit.
2. It results from the working of the apparatus that it is sufficient to establish for
a moment the contact 6, 61 in order that the apparatus may measure.
This contact could be established by the aid of a small electro-magnet actuating
the part 6 and traversed by a periodical current of short duration by means of a
second special circuit. I can thus have a single clockwork for a series of counters.
The arrangement I am about to describe allows, by means of a single special
circuit:
(a) of employing a special source of electricity to operate the electro-motors of a
series of counters.
(b) of dispensing with the special clockwork for each apparatus.
The contact 43, 43' is then dispensed with and the arrangement of the contact 6, 6¹
is represented in Figure 13. A spring 58 acting on the arbor 16 to which is fixed
the part 6' of the contact keeps the circuit of the electro-motor closed. The contact 6¹
is governed on the one hand by the electro-motor B itself which tends to keep it in
the closed position and on the other hand, by a weak electro-magnet with wire of
great resistance 59 continuously put in derivation on mand n which tends to with-
draw it from 6. (See Figure 13b which is, a section on the line p, p of Figure 13).
Assuming the points m and are placed in connection with the source of electricity
the current then passes into B from one part through 6, 61 and into 59. from the
other and the contact is kept in place by the action of B and of the spring 58.
The electro-motor works in the ordinary way until contact is broken at 6, 6¹ by the
displacement of the bobbin 3 of the electro-dynamometer A. At this moment the
electro-magnet 59 acting only on 6' this latter withdraws itself from 6 and the apparatus
returns to its position of rest and remains there during the action of 59.. When the
current ceases the piece 6' falls on 6 under the action of the spring 58.
By these means, the apparatus effects a measuring operation at each time that the
points m and n are put in connection with the source of electricity. It is thus
sufficient for a single clockwork movement breaking momentarily at regular intervals
of time the communication between the points m and n and the source of electricity
to operate a series of counters under the conditions above described.
"
Having now particularly described and ascertained the nature of the said inven
tion and in what manner the same is to be performed, I declare that what I
claim is
'
(1) A meter or apparatus for measuring the strength of continuous or alternating
electric currents formed by the combination of the following parts which together
constitute the apparatus, that is to say-
(a) A torsion electro-dynamometer A constructed of fixed coils 1-1 of thick
wire or of copper strips and of a movable bobbin 3 wound with fine wire in
combination with a torsion spring 7 acting on the axis of the movable bobbin
and of a contact piece 6 governed by the bobbin.
(6) An electro-motor B formed by the bobbins of the electro-magnets 9, 9,
provided with pole pieces 12, 12 acting on the armature 10 which transmits
its rotary movement to the spring 7 of the torsion electro-dynamometer; the

page_text: said electro-magnet 9-9 also winding up the clock movement D by. means
of the oscillating bar 13, of the pawl 44 and of the ratchet 36, and actuating
the contact piece 6¹ by means of the tappet 15.
(c) A frictional brake. or clutch arrangement constructed of the pieces 48-49-
491 for registering exactly the sum of the proportional angles y or product
Ex I. In combination with this frictional brake or clutch arrangement à rod 53
formed at its end with a slot 54, the length of which can be regulated by means
of a screw 57, this rod 53 having for object to transmit to the piece 49 of the
frictional brake or clutch arrangement a rotary movement equal to the angle y.
(d) A clock movement D wound up by means of satellite wheels 39 and 40 for
establishing at 43-43' at regular intervals an electrical contact of very short
duration for the working of the electro-motor B, this clock movement being
adapted to be started automatically by means of levers 60, 63, 65, and of the
screw 64 placed on the arm 22 of the oscillating bar 13.
(e) A speed regulator or governor C working by means of satellite wheels 26
and 27, the frame 28 of which in assuming an inclined position acts as a brake
on the wheel 33 driven by the toothed wheel 25 which is fixed on the shaft S.
In electrical counters or meters the use of the frictional brake or clutch
gement described in claim 1 (c) for the purpose of registering on a counter the
of variable angles.
Dated the 13th day of October 1888.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London,
Agents for the Applicant.