Improvements in Electrical Measuring and Indicating Apparatus.
Year: 1887

page_text: Date of Application, 26th Mar., 1887
Complete Left, 24th Dec., 1887
Complete Accepted, 16th Mar., 1888
Improvements in Electrical Measuring and Indicating Apparatus.
[Communicated from abroad by THE FIRM OF SIEMENS AND HALSKE, of 94, Markgrafen
Strasse, Berlin, in the Empire of Germany, Electrical Engineers.]
Improvements in Electrical Measuring and Indicating Apparatus.
I, CHARLES DENTON ABEL of No. 28 Southampton Buildings, Chancery Lane in
the County of Middlesex, Consulting Engineer and Patent Agent, do hereby declare
the nature of this invention to be as follows:-
This invention relates to the measuring and indicating of quantities of any kind
such as the difference of potential between two points of an electrical circuit, the
height of a water level, the velocity of a stream &c., the object of the invention being
to render such indication and measurement easy and reliable without the employment
of sensitive measuring instruments, which would require the attendance of experts and
careful adjustments from time to time.
This object is effected by the use of two parallel electrical circuits supplied from one
and the same source of electricity.
In the one circuit (termed the "regulating circuit") apparatus are introduced that
serve to maintain the strength of current constant in the second circuit (termed the
measuring circuit). This is effected in the case of a constant difference of potential
between the points where the two circuits branch off, by causing a decrease of
resistance between two points of the measuring circuit, to result in the production
of an equal increase of resistance between two other points of this circuit, so that the
total resistance in the measuring circuit remains constant. In the case of a variable
lifference of potential on the other hand, it is effected by causing the decrease or
ncrease of the difference of potential to result in a proportionate decrease or increase
of the total resistance of the measuring circuit.
The application of the said invention to the measurement and indication of the
ifference of potential between two points of an electrical circuit may, for example be
ffected as follows.
From the two main conductors which lead from a current producer to the outer
ircuit, and whose difference of potential is to be measured, branch firstly the

page_text: regulating circuit, in which are included in series the coils of the field magnets and
those of the armature of an electrical motor and secondly the measuring circuit in
which are included in series, firstly the coils of a solenoid with core, then a number
of resistance coils of the measuring apparatus, and then a contact lever. The solenoid
has a pivotted iron frame surrounding it, with the axis of which is connected a two-
armed lever of insulating material, each end of which carries a fork of conducting
material. Under the prongs of these forks are two pairs of mercury cups so arranged
that when the lever is in a horizontal position, both pairs of mercury cups are out of
contact, but when the lever is inclined in one direction or the other, the one or the
other fork connects up its pair of mercury cups.
The four cups are respectively in connection with the four ends of the coils on the
limbs of the field magnets, so that by the inclination of the fork lever in one direction
the coil of the one limb is short-circuited and by its inclination in the other direction
the coil of the other limb is short-circuited. The action is therefore as follows.
With the normal current tension at the terminals of the electrical generator, the frame
of the solenoid is so placed that the fork lever is horizontal, and thus the coils of both
limbs of the field magnets of the electrical notor are included in series in its circuit.
The coils of the two limbs being so arranged as to magnetise these to an equal degree
but in contrary directions, no rotation of the armature of the motor can ensure while
the above mentioned normal tension exists. But as soon as this tension increases or
decreases, the action of the solenoid causes its frame to turn on its axis so as to short
circuit the coil of the one or the other limb of the field magnets, whereby a rotation
of the armature of the motor will ensue. The axis of the armature is connected by
suitable gearing with the axis of the measuring apparatus, which carries a pointer
made to travel over a graduated scale by the movement of the armature, and with it
moves the before mentioned contact lever of the resistance coils, which lever slides in
frictional contact with contact plates connecting the contiguous ends of two of these
coils arranged in series. Thus on the contact lever and pointer being turned in one
direction, more and more resistances are included in series with the solenoid until the
proportion of total resistance between the points of connection of the measuring
circuit with the main circuit to the current-tension existing between these points again
becomes the normal one. The fork-lever then resumes its horizontal position, and
the movement of the armature of the motor ceases. If on the other hand the fork
lever is inclined in the contrary direction, the resulting rotation of the arinature and
motion of the contact lever and pointer in the contrary direction will cause more and
more resistances to be cut out of the circuit of the solenoid until the normal ratio above
mentioned is re-established. The pointer will in each case indicate upon the scale the
current tension existing at the time in the main circuit.
Instead of a solenoid with pivotted frame two electro magnets may be used between
the opposite poles of which is a metal tongue connected to the one end of each of the
coils of the field magnets of the motor and making a contact which short circuits the
one or the other of these coils according as it is attracted by the one or the other
electro-magnet.
Also a step by step ratchet mechanism actuated by electro magnets may be employed
in place of the motor.
To adapt the above described invention to the indication of water lovels, the above
described apparatus may be arranged as follows. A float on the water is connected
to one end of a chain passing over a pitch wheel and guide roller and having a balance
weight connected to its other end, so that by the rise or fall of the water level and
its float, a rotary motion will be imparted in one direction or the other to the pitch
wheel and consequently also to a contact lever fixed on the axis thereof, which slides
over contact plates connecting together a number of resistance coils arranged in series,
and which will call the second set of resistance coils, this lever being connected to
the one end of the coil of one of the above described electro-magnets which act upon
the moveable tongue.
The other end of this coil is connected to the set of resistances
described in the first arrangement, forming part of the measuring circuit, which passes
from these resistance coils to the one pole of a battery, the other pole of which is

page_text: connected to the first coil of the second set of resistance coils through earth plates.
The regulating circuit consists in this case of two parallel branch circuits, one of which
is formed by the coil of the second of the before described pair of electro-magnets,
while the second is formed by the coils of the field magnets and armature of the motor
arranged in series. The two series may however be combined in one if the resistance
of the field magnet coils is taken so small, that the short circuiting of the coil of the
one limb does not materially diminish the total resistance of the circuit. Also, instead
of arranging the coil of the field magnets and armature of the motor in series, a shunt
arrangement may be adopted.
The action of the apparatus is as follows:
By the rising or falling of the float, a greater or less number of resistance coils of
the second set are included in the measuring circuit, thereby decreasing or increasing
the force of the electro magnet included in that circuit, and thereby causing the
tongue to be moved to the one side or other.
These movements effect the short circuiting of the coil of the one or other limb of
the field magnets of the motor and thus produce the rotation of the armature and
the movement of the pointer and contact lever of the first set of resistance coils until,
as explained with the first arrangement, the normal ratio is again established, when
the pointer will indicate either the actual water level or its deviation from the normal
level on the graduated scale.
Dated this 26th day of a 1007

page_text: COMPLETE SPECIFICATION.
Improvements in Electrical Measuring and Indicating Apparatus.
I, CHARLES DENTON ABEL of 28 Southampton Buildings Chancery Lane in the
County of Middlesex Consulting Engineer and Patent Agent do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:-
This invention relates to the measuring and indicating of quantities of any kind
such as the difference of potential between two points of an electrical circuit, the
height of a water level, the velocity of a stream &c. the object of the invention being
to render such indication and measurement easy and reliable without the employment
of sensitive measuring instruments, which would require the attendance of experts and
careful adjustments from time to time.
This object is effected by the use of two parallel electrical circuits supplied from one
and the same source of electricity.
In the one circuit (termed the "regulating circuit ") apparatus are introduced that
serve to maintain the strength of current constant in the second circuit (termed the
"measuring circuit"). This is effected in the case of a constant differential of
potential between the points where the two circuits branch off by causing a decrease
of resistance between two points of the measuring circuit, to result in the production
of an equal increase of resistance between two other points of this circuit so that the
total resistance in the measuring circuit remains constant. In the case of a variable
difference of potential on the other hand, it is effected by causing the decrease or
increase of the difference of potential to result in a proportionate decrease or increase
of the total resistance of the measuring circuit, so that the ratio between difference of
potential and total resistance remains constant in the measuring circuit.
The application of the said invention to the measurement and indication of the
difference of potential between two points of an electrical circuit may for example be
effected as follows.
Referring to the diagram Figure 1 of the accompanying drawings from the two
main conductors A' A³ which lead from a current producer D to the outer circuit,
and whose difference of potential is to be measured, branch firstly the regulating
circuit in which are included in series by means of the conductors and m² starting
from the points L and M' the coils S¹ S² of the field magnets and those A of the
armature of the electrical motor M and secondly the measuring circuit starting
from the point M² of A² and passing through m² firstly to the coils of a solenoid E
with iron core, thence through m³ to a number of resistance coils w of the measuring
apparatus, and thence through the contact lever hand conductor to the circuit A³
at L².
The solenoid E has a pivotted iron frame B surrounding it with the axis of which
is connected a two-armed lever H H of insulating material each end of which carries

page_text: a fork G¹ G² of conducting material. Under the prongs of these forks are two pairs
of mercury cups u² n², n³n so arranged that when the lever H H is in a horizontal
position, both pairs of mercury cups are out of contact, but when the lever is inclined
in one direction or the other, the one or the other fork connects up its pair of
mercury cups.
The two cups n n are respectively in connection through leads p¹² with the two
ends of the coil S¹ of the field magnets of the motor M, and the cups n³n are in
connection with coil S through leads p³ p so that by inclination of the forked
lever HH in one direction the coil S¹ of the one limb is short-circuited and by its
inclination in the other direction the coil S2 of the other limb is short circuited. The
action is therefore as follows. With the normal current-tension at the terminals of
the electrical generator D the frame B of the solenoid is so placed that the forked
lever is horizontal and thus the coils of both limbs of the field magnets of the electrical
motor are included in series in its circuit. The coils S1 S2 of the two limbs being so
arranged as to magnetise these to an equal degree but in erary directions, no
rotation of the armature of the motor can ensue while the abo mentioned normal
tension exists. But so soon as this tension increases or decreases, the action of the
solenoid causes its frame to turn on its axis so as to short circuit the coil of the onc
or the other limb of the field magnets whereby a rotation of the armature of the motor
will ensue. The axis of the armature is connected by suitable gearing with the axis y
of the measuring apparatus which carries a pointer made to travel over a graduated
scale by the movement of the armature and with it moves the contact lever of the
resistance coils w which lever slides in frictional contact with contact plates c con-
necting the contiguous ends of two of these coils arranged in series. Thus on the
contact lever and pointer being turned in one direction, more and more resistances
are included in series with the solenoid until the proportion of total resistance
between the points of connection of the measuring circuit with the main circuit to the
current tension existing between these points again becomes the normal one. The
forked lever H H then resumes its horizontal position coil S is included in the circuit
and the movement of the armature of the motor ceases. If on the other hand the
forked lever is inclined in the contrary direction owing to a decrease of tension
between Land M² the resulting rotation of the armature and motion of the contact
lever and pointer in the contrary direction will cause more and moro resistances to be
cut out of the circuit of the solenoid until the normal ratio above mentioned is
reestablished. The pointer will in each case indicate upon the scale T the current
tension existing at the time between the leads A¹ and A².
Instead of a solenoid E with pivotted frame B two electro magnets E' E Figure 2
may be used between the opposite poles e e² of which is a metal tongue Z connected by
lead a to the one end of each of the coils SS of the field magnet of the motor and
making a contact at or which short circuits the one or the other of these coils
through leads a' or a² accordingly as it is attracted by the one or the other electro
magnet.
Also a step by step ratchet mechanism actuated by electro magnets may be employed
in place of tho motor.
To adapt the above described invention to the indication of water levels the above
described apparatus may be arranged as shewn by way of example at Figure 2. A
float Q on the water is connected to one end of a chain K passing over a pitch wheel R
and guide roller 7 and having a balance weight P connected to its other end, so that
by the rise or fall of the water level and its float, a rotary motion will be imparted
in one direction or the other to the pitch wheel R and consequently also to a contact
lever C fixed on the axis thereof which slides over contact plates C connecting
together a number of resistance coils to w arranged in series and which I will call the
second set of resistance coils this lever being connected through and m' to the one
end of the coil of the above described electro magnet E. The falling or rising of
the water level consequently produces an increase or a decrease in the resistance
between the points q' and q². The leads situated between y and belong to the
measuring circuit which passes from through electro maguet E' and resistance w of the

page_text: measuring apparatus to the one pole of the battery V, while the other pole of the
battery is connected to q through earth plates.The regulating circuit consists
in this case of two parallel branch circuits one of which is formed by the coil of the
second electro magnet E while the second is formed by the coils of the field magnets
and armature of the motor arranged in series. The two series may however be com-
bined in one (the coils of ES Sand of the armature being all arranged in series)
if the resistance of the field magnet coils is taken so small, that the short circuiting
of the coil of the one or other limb does not materially diminish the total resistance of
the circuit. Also instead of arranging the coil of the field magnets and armature
of the motor in series a shunt arrangement may be adopted. In this case also only
one circuit is required for the regulation.
The action of the apparatus is as follows:-
When by the rising and falling of the water level the resistance between q³ and q²
is decreased or increased, as above explained the tongue Z makes contact with
cither or whereby in the first case the coil Sand in the second case the coil S*
will be short circuited and the motor will consequently he actuated so as to rotate the
contact lever and pointer Z of the measuring apparatus in one direction or the
other until the lever he has included or excluded sufficient resistances to bring back
the total resistance in the measuring circuit to its normal value whereupon the motor
will be put out of action again and the position then assumed by the pointer Z will
show how many resistances we have been included or excluded between and q or in
other words what angle the contact lever and chain wheel I have been moved
through and consequently the extent to which the water lever has risen or fallen.
For practical use the chain wheel R the distance between two contact plates C. C.
and as also the division of the scale may be so proportioned to one
another that the alteration of the water level from the normal to the extent of a
unit of measurement shall cause the pointer Z to move either a whole division or a
certain fraction thereof on the scale so that the water level can be read off directly
therefrom. Or the scale may be so marked as to enable the actual height of the water
level to be read off.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. Electrical apparatus for automatically measuring or indicating quantities wherein
two electrical circuits supplied with currents from the same source are so arranged
in combination with each other and with variable resistances that when the current
in the one circuit is subject to variations due to variations in the quantity to be
measured or indicated it causes the current in the second circuit to actuate an electro
motor whose movement indicates the desired measurement and varies the resistances
in the first circuit so as to restore the current therein to its normal strength
substantially as described.
2. The use for automatically maintaining constant the strength of current in the
circuit of electrical measuring apparatus such as is referred to in the preceding claim
of an electro motor the circuit of which is branched from an electrical generator
parallel to the measuring circuit and the coils of whose field magnets are so wound
and connected to the regulating circuit and controlled by the measuring circuit that
on an increase or decrease of current taking place in the measuring circuit the motor
is actuated and is thereby made to include or exclude resistances in or from the
circuit so as to restore its current to the normal strength, substantially as and for the
purpose described.
3. In electrical measuring apparatus such as is referred to in the preceding claims,
the use of regulating apparatus consisting of a solenoid with iron core in combination
with a pivotted iron frame carrying a double ended lever having a contact fork at
each end, which according as the frame and lever are tilted to the one side or the
other by variations in the current passing through the solenoid are made to dip into
one or other of two pairs of mercury cups that are respectively in contact with the

page_text: ends of the two oppositely wound coils of the electro motor substantially as and for
the purposes described.
4. In electrical measuring apparatus such as is referred to in the first claim the
use of measuring and indicating mechanism consisting of a series of insulated contact
plates arranged in a circle and so connected to a series of resistances that a contact
lever mounted on a central axis in being moved in one direction or the other in
contact with the said plates by the motion of the electro motor in the regulating circuit
is made to include or exclude one or more of the resistances in or from the measuring
circuit the motion of the lever being indicated by a pointer on a circular graduated
scale or dial substantially as and for the purposes herein described.
Dated this th of Deambon 1007