Improvements in Electrical Measuring Instruments.
Year: 1898

page_text: Date of Application, 22nd Mar., 1898-Accepted, 20th May, 1898
Improvements in Electrical Measuring Instruments.
I, EDWARD WESTON, of No. 114 William Street, Newark, in the County of
Essex and State of New Jersey, United States of America, Electrician, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following state-
ment;-
There are many places in the use of electrical measuring instruments where
it is desirable to utilize two instruments at one and the same time, either for the
purpose of measuring in one case the quantity of current and in the other the
potential or voltage, or for measuring independent quantities of current and
independent voltages or potentials. It is also often desirable to combine two
instruments of the character indicated upon a common support in a single
enclosing case for the purpose of transportation or usage and with a view of
making the entire structure as light and compact as possible, as for instance in
connection with motor vehicles and in such places where either continuous or
successive transportation is often necessitated. I have also found it desirable
to make comparative readings upon independent instruments, either
potential or quantity, and in such an event it is important to have the indicating
needles so located with relation to each other that instantaneous comparative
readings may be made. It was with these several objects in view that the present
invention was devised.
as to
My invention will be fully understood by referring to the accompanying draw-
ings, in which,
Figure 1 is a plan view of my novel compound instrument with the covering
or casing removed so as to disclose the interior structure;
Figure 2 being a sectional view thereof on the line x-x, some of the parts
being shown in elevational view.
Referring to the drawings in detail:-
B represents the base of the instrument provided with pairs of lugs or ears L L,
L L for securing it permanently in place. E E are standards secured to the
base B by screws ss, $77. M and M' represent permanent magnets with their
poles oppositely located, as shown at N S N S, said magnets being supported by
cross-bars to which in turn is secured, by screws tt, a dial plate D.
PP, P P are curved soft iron pole pieces secured thereto by screws S¹ S1, S¹ S¹.
HH represent soft iron cylinders secured to brass or other diamagnetic bars C C¹,
by screws ss, s5 55, said bars being in turn secured to the outer ends of the pole
pieces P P, P¹ P', there being a sufficient space between the cylinders H H and
curvilinear pole pieces P P, P P for the movement of movable coils c c.
bb, bare pairs of bridges of diamagnetic material electrically insulated
from but connected at their opposite ends by screws to the pole pieces P P, P¹ P¹,
their function being to act as supports for the pivots of the movable coils c c.
I and I are indicating needles connected to the pivots which support the movable
coils and provided with counterweights w³ ³; s $2 and $1 53 being oppositely dis-
posed pairs of retractile springs connected also to the pivot supports and the

page_text: bridges bb, b1 61 of the respective instruments and so adjusted that when there
is no current passing through the movable coils the index needles I and I'
point, as shown, to the zero points of independent scales upon the common dial
plate D.
The movable coils c c and the circuit connections through the pairs of retractile
springs and s³ to the conductors wow, w w¹ and the manner of sustaining
the soft iron or other magnetic cylinders H H by means of screws 54 54, 55 55 upon
diamagnetic bars CC, together with the curved pole pieces P P, PP, all being
clearly shown in Figure 1.
B¹ B³, B³ B* are pairs of binding posts connected respectively to the conduc-
tors ww, w¹ w running to the movable coils and movable parts of the two
independent instruments, said binding posts being secured to the underside of
the base or support B by pairs of screws r r, r r .
In the present instance I have illustrated the indicating needles I and I'
as being oppositely disposed with relation to a common scale calibrated alike on
opposite sides, thus indicating that the instruments are both voltmeters
or ammeters as the case may be. It is obvious that one of the instruments, for
instance the one having the needle I might have its scale calibrated to measure
the quantity of current, while the instrument having the indicating needle I'
might have its scale calibrated to indicate the voltage or potential. It is apparent
that the disposition of the indicating needles I I' in the manner shown in con-
nection with a common scale renders it an easy matter to make comparative read-
ings where two instruments are attached to a single base or enclosed in one casing,
and this by reason of the fact that the calibrations are extended laterally in
parallel lines to points approaching the arcs of the swinging index needles or
hands, as clearly shown in Figure 1 of the drawings.
I believe that it is broadly new with me to thus rigidly combine two electrical
measuring instruments having a common scale in such manner that the readings
thereof may be observed at one and the same instant, and my claims are generic
as to this feature.
I believe it is also broadly new with me to combine the movable parts of two
current measuring instruments with a single pair of magnets so as to afford or
offer substantially constant magnetic fields to such movable parts, and my claims
are to be construed also as generic in this particular.
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. Two current measuring instruments attached to a single or common base
and having their indicating needles so located that independent readings may be
taken at the same instant, substantially as described.
2. Two current measuring instruments attached to a single or common base
and having their indicating needles so located with relation to a
common scale
that independent readings may be taken at the same instant, substantially as
described.
3. Two current measuring instruments attached to a single or common base,
in combination with a single dial plate provided with a scale common to the
index of both instruments, substantially as described.
4. Two current measuring instruments each provided with an index needle or
hand operatively connected with the rotary or movable part of its own instrument,
said rotary or movable parts being located in the magnetic fields between the
opposite ends of a pair of energizing magnets, substantially as described.
5. Two current measuring instruments attached to a common base with their
movable parts located in the magnetic fields between the opposite ends of two
magnets, in combination with index needles or hands and a single dial plate pro-
vided with one or more scales towards which both of said indexes point during
their entire range of movement, substantially as described.

page_text: 6. A combined instrument for measuring electrical currents, consisting of two
instruments enclosed in a single casing and a single dial plate having a scale
common to the movable parts of said instruments, substantially as described.
7. A pair of electrical measuring instruments having movable index needles or
hands normally pointing towards each other, in combination with an intermediate
dial plate and a scale calibrated alike for both instruments, the calibrations of
said scale extending in lines parallel with the normal position of the index needles
and to points substantially equally distant from said needles for all ranges of
movement, substantially as shown and described.
8. A pair of electrical measuring instruments having each a movable index
needle or hand, in combination with a single scale located between said needles or
hands, the calibrations of said scale extending to points substantially equally
distant from the ends of the needles for all ranges of movement thereof, substan-
tially as described.
9. Two electrical measuring instruments having movable index needles or
hands I and I attached to movable coils cc located in the magnetic fields between
pole pieces P P, P¹ P₁ secured to the ends of permanent magnets M and M', in
combination with a dial plate D having an intermediate scale common to both
index needles or hands, and independent binding posts B1 B2, B3, B4 having
circuit connections with the movable coils, all of said parts being rigidly attached
to a common base or support, substantially as described.
Dated this 22nd day of Manab 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.