Year: 1887

page_text: I, SYDNEY PITT of Sutton in the County of Surrey, Gentleman, do hereby declare
the nature of this invention, and in what manner the same is to be performed, to bo
particularly described and ascertained in and by the following statement :-
The present invention has for its object the construction of an apparatus capable of
measuring the electric energy of any current.
Up to the present to obtain the energy it has been necessary by calculation to find
the product of the electro-motive force of the current to be measured into its quantity,
say, by multiplying the number of volts by the number of amperes per second, this
gives the number of watts, the watt being the unit of energy.
My new meter indicates directly the number of watts of the electric current passing
through the instrument without having recourse to calculation.
It is composed-1. Of an electro-dynamometer of special construction. 2. Of a
clock movement measuring time. 3. Of a toothed cylinder making one turn in
a minute, constructed in conformity with my previous patents viz: No. 175683,
No. 75158, No. 137048, No. 636980. 4. Of a counter and dials.
The recording of the watts is performed in the same way as the current in
my former patents, by means of an oscillating needle placed under the influence of the
electro-dynamometer, and the larger or smaller deviation of the needle, in front
of the toothed cylinder which is kept in regular and continuous revolution, representing
the time unit determines a variable number of contacts which cause motion to
the ratchet wheel by which the registering train is controlled.
The drawings annexed give an exact and complete representation of the apparatus.
Figure 1 is a front elevation of the meter. Figure 2 is a side elevation. Figure 3 is
a back view. Figure 4 is a plan view of the apparatus. Figures 5, 6, and 7
shew details of the electro-dynamometer. Figure 5 shews in section the fixed exterior
bobbin A and a side view of the moving bobbin B.

page_text: Figure 6 shews a side view of the fixed bobbin, and the bobbin B is represented in
section. Figure 7 is a plan view of the two bobbins.
Figure 8 is a diagram representing the passage of the current through the apparatus.
These figures are of the actual size of the instrument and the arrows indicate the
direction of the current.
The different parts of the apparatus are mounted in a fixed frame represented in the
figures by the letter Y; this frame is attached to a base X.
It is
It is
The electro-dynamometer is composed of two annular bobbins A and B. The
exterior bobbin A is held by the four grooved wooden blocks a screwed to the frame.
It is formed of two parallel and perfectly similar rings a and a¹, figures 5 and 7,
connected together; in them the passage of the current is parallel. Each of these
rings is composed of a flat ribbon conductor of section duly proportioned to the
maximum intensity of the currents to be measured. The conductor of suitable length
is rolled upon itself;
it is seen in section in Figure 5. The different convolutions are
insulated the one from the other by means of bands of woven fabric a² or in any other
suitable manner. The upper end of each of these conductors by which the main
current enters is attached to the piece of copper W³ fixed upon but insulated from the
frame Y and connected to the terminal 3. Their lower ends, by which the current
issues pass out at W to the terminal a¹. The inner bobbin B is movable.
placed within the bobbin A in such a way that their centres of figure coincide.
composed of a single wooden ring on which is wound a very long and fine wire with
an electrical resistance of about one thousand Ohms, it forms a shunt on the main
circuit in which the current to be measured passes. This bobbin pivots at 6b on
vertical trunnions at band suitable adjustment is provided. In order to obtain
sufficient freedom and sensibility it is supported at its centre by a silk thread carried
by a flexible arm, as is shewn in figures 5 and 6. At the top of the upper
trunnion of the bobbin B an indicating needle C is fixed which in consequence of the
influence of the current upon the bobbin B oscillates around the axis of this bobbin,
pointing by means of the index with which it is provided, to the divisions of the
scale D, corresponding to the oscillations of the bobbin B. This needle C, the
function of which has already been fully described in my former patents hereinbefore
. mentioned carries at its extremity underneath the scale D a wedge of bronze c
figure 2, which coming against the teeth of the cylinder E, raises the movable frame F
on which the scale D is fixed, on each encounter with a tooth of the cylinder. The
further cross-piece f, of the movable frame F being held between the branches of a
fork y causes by its movement the rod to rock pivotting upon an arm g² fixed to the
frame of the apparatus. It carries upon the other side of its pivot a piece g³,
to the lower end of which the tooth G is attached which gives motion to the ratchet
wheel H which controls the registering train of wheels of which the function
is well known.
As in my former patents already quoted the clock movement is driven by electricity; it
is composed of four fixed bobbins which, under the influence of the current, cause the
armature which is of a piece with the axis I, to oscillate. This carries with it the fly
wheel producing in this way the movement which is transmitted to the tooth
cylinder E, and this is regulated to move at the rate of one turn per minute. The
mechanical construction of this cylinder is in all respects as described in my
former patent.
The needle C is kept at zero of the scale so long as the apparatus is at rest by the
influence of an adjustable spring K which acts upon the lower trunnion of the
movable bobbin B. c is the adjustable counterpoise of the needle C, and fare
the adjustable counterpoises of the movable scale carrying frame F which turns about
the axis f'.
The wooden base X carries the four terminals xxx the use of which I
shall presently state.
The diagram figure 8 represents the progress of the current in the different parts of
the apparatus. The current enters by the terminal and passes by the thick
conductor W to the two ribbon conductors a a¹ forming the bobbin A. The current

page_text: flows in the same direction in each of these annular conductors and passes out by the
conductors WW, connected to the thick conductor W leading to the terminal ¹
from whence the current is taken to the lamps or is otherwise utilised. The return to
the apparatus is by the terminal and thence by the terminal 2 back to the electric
source. The interior movable bobbin B receives the current by the conductor W³
carrying the spiral spring to which is connected one of the ends of the fine wire of
the movable bobbin. The conductor Wa is connected to the thick conductor W. The
current traverses the bobbin B and passes out by the lower spiral ¹ which is carried
by the conducting arm W connected to the thick return conductor W³.
Under the influence of the current the bobbin B oscillates in virtue of the
well known law of direct attraction and repulsion exercised the one on the other
by electric currents.
22
The two springs and have for their object to carry away the current without
interfering with the liberty of movement of the bobbin B. This arrangement however
has been fully described and represented in one of my previous patents, No. 636986.
This electro-dynamometer which I have invented is constructed on the principle of
that of Weber.
The clock movement is operated by a derived current. The conductor We
branching out from the thick conductor W2 leads the current to the upper bobbin L;
it passes through this and then the bobbin L' placed beneath the first and leaves
by the conductor W which leads it to the automatic circuit breaker N or regulating
organ of the balance already described in my previous patents already quoted; from
thence the current passes by the conductor W to the two bobbins M M² to reach the
thick return conductor W by the conductor W.
It should be remarked that in my former meters the regulating organ of the
balance is composed of a single flat spring with contact spring and small arm
engaging in a recess in the axis of the armature. In the present apparatus I employ
the same arrangement repeated to insure a better working of the meter.
I do not desire to limit myself exactly to all the details above mentioned nor
to combine in all cases the two parts of the apparatus, as my electro-dynamometer can
be used alone or adapted to registering apparats of a different model.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed I declare that what I claim is :-
1. The combination in an electro-dynamometer of two annular bobbins A, B, of
which one A which is fixed and is composed of two parallel and similar rings
each consisting of a ribbon conductor of section proportioned to the maximum
intensity of the current to be measured, represents intensity; and the other B,
moving in a vertical plane and suspended by its centre within the bobbin A and
covered with a very long fine wire, represents the electro motive force, the two
bobbins reacting the one on the other as has been described.
2. The combination of this electro-dynamometer with the mechanical time
measuring organs by means of the cylinder E rotating under the control of the clock
movement, of the driver G and of the ratchet wheel H actuating the registering
apparatus so as to effect the automatic registration of the total energy delivered by a
current in a given time.
3. The apparatus substantially as described and represented in the annexed
drawings.
CARPMAEL & Co.,
Agents for the Applicant.