Improvements in Electrical Measuring Instruments.
Year: 1898

page_text: Date of Application, 22nd Mar., 1898-Accepted, 4th Feb., 1899
COMPLETE SPECIFICATION.
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
statement:-
My invention relates to electrical measuring instruments designed chiefly for
use in connection with the measurement of alternating currents of electricity and
will be fully understood by referring to the accompanying drawings, in which,
Figure 1 is a plan view thereof illustrating the apparatus as attached to a
switchboard, the operative parts thereof being shown in dotted lines.
Figure 2 is a vertical sectional view taken through the body of the instrument,
the operating coils, their means of suspension from the lid of the instrument, the
binding posts connected thereto and the index needle being shown in side
elevational view.
Figure 3 is a transverse sectional view taken through the body of the instru-
ment and its operating coils, the index needle being shown in plan view and as
adapted for use in connection with a scale, the zero point of which is located at one
side of the instrument.
Figure 4 is a vertical sectional view taken through the body of the instrument,
the operating coils and index needle being removed.
Figure is a plan view of a modified form of the instrument adapted for use
as a voltmeter, illustrating also means for controlling an additional index needle
by hand.
Figure 6 is a vertical sectional view taken through Figure 5 illustrating the
spool or spools upon which the stationary or energizing coils (not shown) are sus-
pended and illustrating also the indicating needle together with a mechanically
actuated indicating needle and its extraneous or exposed operating handle.
Figure 7 is a transverse sectional view taken through the body of the instru-
ment, Figure 6, the indicating needle being shown in plan view at its zero point.
Figure 8 is a vertical sectional view taken through the body of the instrument
illustrated in Figures 6 and 7, the hangers or posts which support the instrument,
one end of the sustained spool or spools which support the stationary energizing
coils and the means of attaching the parts securely to the underside of the remov-
able lid or cover of the enclosing casing, together with the pivot support of the
mechanically actuated indicating needle, all being shown in elevational view.
It is a well known fact that in the use of electrical measuring instruments
where there are wide fluctuations of current to be measured, the index needle
and movable parts connected thereto are often materially damaged by being
swung violently to their extreme limits of vibration.
With a view of over-
coming this objectionable feature I have so arranged my novel current measuring
instrument that the energizing coils and the movable parts immediately con-
nected thereto are suspended in a substantially non-viscous liquid in such manner

page_text: that the same is caused to exert a retarding influence as the parts are acted upon
by varying currents, and this feature constitutes one of the essential elements of
my invention hereinafter described and claimed.
I have also discovered that where the current conveying conductors are sur-
rounded or insulated by hard rubber sleeves or tubes, light will in time so affect
the surfaces of such tubes or sleeves as to often cause current leakage to a damaging
extent, and to overcome this objection I protect the binding posts thus insulated
with surrounding sleeves or caps of an opaque insulating material.
It is also desirable in the use of central station instruments that there should
be some means provided for enabling the engineer or attendant to ascertain at a
glance from a distance, merely by observing the ampere and voltmeters of the
system, whether or not the generator or generators is or are meeting the require-
ments thereof and to this end I provide with each instrument an enclosed movable
index hand, adapted to be moved over the same dial as does the movable index
needle or hand controlled by the current, and provide the same with extraneous
means in the nature of a handle or knob for placing by hand the first mentioned
index needle over some definite point of the scale.
Referring now to the drawings in detail:-
C² represents the retaining casing, preferably made of cast metal and of the
conformation shown in plan view in Figure 1 and with a downwardly extending
rear cylindrical portion C³ as shown in Figure 2; L being a detachable or remov-
able lid or cover secured to the body portion of the casing by screws, and Da
disc shaped bottom secured to the bottom of the casing by thumb screws sy s ²,
the upper portion of said disc being provided with a groove for the purpose of
securing in position a glass or equivalent liquid containing jar or vessel J. Cast
integral with the body part C2 C3 of the retaining casing are upwardly and
radially extending stiffening knees rr adapted to sustain the curvilinear front
surface of the instrument upon which is secured the indicating scale S, as clearly
shown in Figures 2 and 3, the arrangement being such that there is a sufficient
opening or space between the upper portion of this scale supporting part and the
lid or cover L to permit a free swing of the index needle to its extreme limits.
G is a curved glass plate extending entirely across the front of the instrument and
secured to the casing by a supporting frame and screws, as clearly shown in
Figures 2 and 3. Cast integral with the lid L are four downwardly extending
lugs 17 adapted to receive screws tft which pass through a supporting block A
of hard rubber, ebonite, vulcanized fibre or other insulating material.
P Pare
downwardly extending hanger posts properly secured to the block A and sup-
porting bridge pieces bb, which bridge pieces are properly insulated and have
adjustable parts for sustaining the lower and upper ends of a vertically arranged
shaft a which passes through the transverse axis of a movable coil (having a
relatively large number of turns and normally resting in the plane of the axis of
a stationary coil (of relatively few turns and therefore of large current carrying
capacity. The opposite ends of this stationary coil (are secured by screws, as
shown, to conducting plates M³ M³ attached to the underside of the insulating
block and are in turn connected to binding posts B2 B3, the convolutions being 4
sufficiently separated at the middle part, as clearly shown in Figures 2 and 3,
to admit of the free passage of the shaft a so that the movable coil or part C¹
may vibrate or move in opposite directions. It is also apparent on inspection
of Figures 2 and 3 of the drawings that the cross section of each individual turn
or winding of the coil C is of such area that the coil will sustain itself and the 5
individual turns be separated from each other by air spaces sufficient to elec-
trically insulate them.
To the opposite ends of the shaft a are secured oppositely disposed conducting
retractile springs ss (the upper one not being shown) said springs being in turn
connected to the bridges bb, circuit connections being provided therefrom to 5
inding posts B B. To the upper end of the shaft a is attached the index

page_text: needle I, said needle being partially shown in Figure 3 in plan view as located
at the zero point of the scale and in side elevational view in Figure 2.
The outer or index end of the needle I is turned downward at right angles so
as to move laterally in front of the scale S, as is obvious upon inspection of
Figure 2.
w are counterweights for properly counterbalancing the needle.
ee are buffer springs located at opposite sides of the instrument and secured to the
casing by screws extending inward therethrough into lugs h h, as clearly illus-
trated in Figure 3, the function of these springs being to prevent any damaging
influence to the light indicating needle I should it be thrown violently to its
extreme limit in either direction.
O is a liquid, preferably a non-viscous oil, placed within the jar or vessel J
and having preferably such a depth as to cover all of the movable parts of the
instrument except the upper end of the shaft a, the object of this liquid being
as hereinbefore described to act as a damper and also to make the instrument of
a dead-heat nature.
I prefer to use a substantially non-viscous liquid, such as light petroleum oil
which will not evaporate or assume a solid form at the temperatures where such
instruments are generally used, and also for the reason that liquids of this nature
are of highly insulating qualities, it being obvious that a properly selected oil
would effectually insulate the successive turns of the coil C from each other,
but I do not limit myself to my special kind of liquid so long as the same be of a sub-
stantially non-viscous nature, the especial novelty of this feature of my invention
lying in the use of a dampening liquid.
It will be apparent that the instrument may be readily removed from the
switchboard SB by unscrewing the nuts n n from the bolts gg extending through
the eves E E¹ of the retaining casing C² and that the oil retaining jar may be
quickly and easily removed by withdrawing the thumb screws from the
bottom D and an inspection of the parts had from the underside or that the
entire instrument itself may be removed by withdrawing the screws from the lid L
and lifting the parts bodily out of the retaining jar or vessel J.
Referring now to Figure 4 of the drawings for a description of my novel
manner of preventing the evil effects of the oxidizing influence of light upon
hard rubber or equivalent oxidizable sleeves which surround the binding posts,
B and B represent the binding posts designed to convey large quantity currents
to the coil C.
N2 and N³ represent metallic nuts and w² 3 metallic washers, ww being
conducting set nuts so arranged that the terminals of the conductors may be
inserted between the washers 23 and nuts w$ 205.
S2 and S represent hard rubber sleeves designed to insulate the binding posts
B 13 from the lid L, and R2 and R3, are protecting caps of any opaque insulating
material, preferably of such a nature as will not readily oxidize, said caps being
adapted to fit snugly over the outer or exposed ends of the hard rubber sleeves S2 S3
and being held firmly in position by the set nuts 1 25. It will be apparent
therefore that by providing protecting caps of opaque material I am enabled to
prevent the evil effects of light upon the hard rubber sleeves, and I find that with
this arrangement there is absolutely no danger of short circuiting currents
through the surfaces of the insulating sleeves, as was possible before such pro-
tecting caps of opaque material were used.
Referring now to Figures 5, 6, 7 and 8 of the drawings in which like letters
of reference represent corresponding parts to those similarly illustrated in
Figures 1, 2, 3, and 4, h h h h are rectangular hangers, four in number, secured
by screws tttt to the downwardly extending lugs 1117 on the underside of the
removable cover or lid L. said hangers supporting in turn a frame which carries
two spools SS on which is wound in the spaces CC the stationary energizing

page_text: coil or coils not shown, P2 P3 being cross-bars or rods which secure the opposite
sides of the frame and the spool-heads together.
bare bridges electrically insulated from but attached at their opposite ends
to downwardly extending posts P P secured also to the hangers h h acting as
abutting supports for the inner ends of the spools S¹ S³, said bridges supporting in
turn the vertical shaft a of the movable coil C" the shaft being provided with
electrically insulated pivotal supports and oppositely disposed conducting retrac-
tile springs, the circuit connections being through the retractile springs ss,
the movable coil, C' the stationary energizing coil or coils, the pivot bearings, to
the binding posts B B¹.
I is the indicating needle connected to the upper end of the shaft a and in such
manner that when the coil (vibrates back and forth under the influence of the
stationary energizing coil it will vibrate with said vibratory coil.
11
I is a second indicating needle, the free end of which is bent downward at
right angles and in such manner as to extend beyond the downwardly extending
portion of the indicating needle I, said needle I being pivotally supported in
alignment with the shaft a by a pivot pin extending upward through the lid L
and connected in turn to an operating handle H located in the same vertical
plan, said operating handle extending preferably to an accessible point beyond
the scale face of the instrument as clearly shown in Figure 6.
d is a spring located between the needle 11 and the lower face of the lid, said
spring being adapted to give sufficient frictional bearing to the parts to cause
the needle to remain in any position where it may be moved by hand, by or
through the agency of the handle H.
Although I have herein before described my invention as being applicable to
electrical measuring instruments designed chiefly for use in measuring alternating
currents of electricity I wish it understood that many of the details of the entire
structure may be applied to electrical measuring instruments generally.
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. An electrical measuring instrument having the movable coil thereof either
partially or wholly immersed in a dampening liquid, substantially as described.
2. An electrical measuring instrument having its movable coil immersed in
a substantially non-viscous liquid, substantially as described
3. An electrically measuring instrument having its movable coil immersed in
a non-viscous, oil, substantially as described.
4. An electrical measuring instrument having the operative parts thereof sus-
pended from the lid of the instrument in a substantially non-viscous liquid, sub-
stantially as described.
5. An electrical measuring instrument having the operative parts thereof sus-
pended from the lid of the instrument in a substantially non-viscous liquid con-
tained in a jar or vessel located within the casing of the instrument, substantially
as described.
6. An electrical measuring instrument having its operative parts suspended
from the lid of the instrument within a liquid contained in a jar or vessel, said
jar or vessel being in turn supported by a bottom detachably secured to the lower
side of the casing, substantially as described.
7. An electrical measuring instrument provided with a dust-tight casing hav-
ing a detachable lid and bottom, the operative parts of the instrument being
suspended from the lid, in combination with a liquid retaining jar or vessel
filled with a non-viseous liquid, said vessel being sustained by the detachable
bottom so that the operative parts of the instrument are immersed in the liquid,
substantially as described.
8. An electrical measuring instrument having a stationary coil of large cur-

page_text: rent carrying capacity, the individual turns of which are separated from each
other by air spaces, said coil being suspended or supported by points of attach-
ment at its opposite ends and immersed in an insulating liquid, substantially as
described.
9. An electrical measuring instrument having an enclosing casing and a remov-
able lid therefor, a stationary coil of large current carrying capacity having its
individual turns insulated from each other by air spaces and its ends sustained
or supported from an insulating block secured to the underside of said lid, in
combination with a movable coil pivotally sustained within the magnetic field of
said stationary coil and having an indicating needle secured to its rotary sup-
porting shaft, and circuit connections running to binding posts, substantially as
described.
10. An electrical measuring instrument, provided with one or more binding
posts having surrounding insulating sleeves of oxidizable material, such as hard
rubber, in combination with opaque protecting caps for shielding the same from
the action of light, substantially as described.
11. An electrical measuring instrument having its movable parts suspended in
a substantially non-viscous liquid, in combination with an indicating needle and
one or more buffer springs located at the opposite ends of its throw or movement,
substantially as described.
12. An electrical measuring instrument having a dust-tight casing which
surrounds all of the operative parts thereof, said parts being suspended from the
lid, the casing being provided with a detachable bottom for affording access
thereto from beneath, substantially as described.
13. An electrical measuring instrument having all of its operative parts en-
closed in a dust-tight casing detachably secured to a switchboard, said operative
parts being secured to a removable lid, in combination with a detachable bottom
for affording access to the operative parts of the instrument from beneath, sub-
stantially as described.
14. An electrical measuring instrument having its stationary energizing coil
wound upon a spool supported by hangers beneath the detachable lid of the en-
closing casing, in combination with a movable coil pivotally sustained within the
magnetic field of said stationary coil and an index needle or hand carried by the
axis of said movable coil, substantially as described.
15. An electrical measuring instrument having its stationary energizing coil
wound upon two spools, in combination with a movable coil pivotally supported
within the magnetic field between the adjacent ends of said spools and an index
hand carried by the shaft of said movable coil, all of said parts being supported
or suspended beneath the lid of the enclosing casing, substantially as described.
16. An electrical measuring instrument having its fixed or energizing coil wound
upon two spools, in combination with a movable coil pivotally supported in the
magnetic field between the adjacent ends of said spools and supporting an index
needle, together with conductors connecting said coils with binding posts, all of
said parts being secured to the detachable lid of the enclosing casing, substantially
as described.
17. An electrical measuring instrument provided with two index or indicating
needles and a scale wholly enclosed within the casing of the instrument, one of
said needles being operatively connected with the movable part of the instrument
and the other with extraneous means for mechanically moving it to various
positions, substantially as described.
18. An electrical measuring instrument provided with two index or indicating
needles wholly enclosed within the casing of the instrument, one of
said needles being operatively connected with 24 rotary coil located
within the magnetic field of a stationary coil supported by the lid of
the instrument, the other needle being pivotally supported above the
first named needle and provided with extraneous means as a lever for moving it,

page_text: in combination with an indicating scale common to both needles, substantially as
described.
19. An electrical measuring instrument provided with two coils, one of which
is stationary and the other movable, the latter operatively connected with an index
or indicating needle or hand, in combination with a second indicating needle and
a scale common to both needles, all of said parts being sustained by the lid of
the enclosing casing and the second needle pivotally supported and provided with
an operating lever on the outside of the casing, substantially as described.
20. An electrical measuring instrument wholly enclosed within a casing pro-
vided with means for attaching it to a switchboard, the operative parts of said
instrument consisting of a stationary and a movable energizing coil
and a movable index hand carried by the movable coil, in combina-
tion with a second movable index hand and a scale common to both
hands together with extraneous means as a lever operatively con-
nected with the second hand and extending forward through the switchboard to c
point accessible to the attendant, substantially as described and shown.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.
Agents for the Applicant.