IMPROVEMENTS IN INSTRUMENTS FOR DETECTING AND MEASURING ELECTRIC CURRENTS
Year: 1887

page_text: Date of Application, 23rd Mar., 1887
Complete Left, 23rd Dec., 1887
Complete Accepted, 9th Mar., 1888
PHILIP JOLIN of 35 Narrow Wine Street in the city and county of Bristol Engineer
do hereby declare the nature of this my invention for IMPROVEMENTS IN INSTRUMENTS
FOR DETECTING AND MEASURING ELECTRIC CURRENTS to be as follows:-
In instruments commonly called galvanometers as now constructed with a moving
coil on the principal of Thomsons Syphon Recorder" it is usual to attach the magnets
to a horizontal base by means of brackets and to carry the suspension by suitable pillar
or pillars, which also carry the core or centre piece of soft iron which is inside to
strengthen the field. Now in my improved arrangement I propose to attach the
magnets direct to a rigid horizontal or vertical plate or extension thereof which also
carries the centre core which I make preferably of a compound magnet, I carry the
lower suspension by a suitable spring carried by the horizontal or vertical plate; in
the vertical forme the suspension may be lengthened by drilling a hole in through the
neutral point of the magnets and allowing the suspension to pass through this hole to
the spring aforesaid, the electric connection being made from said plate through the
spring and lower suspension to the coil. I attach the top suspension when used to
another plate or to a tube with a suitable metal head capable of a rotary motion around
in a horizontal plane, to adjust the coil, and with another adjustment to raise and lower
the coil, this top plate forms the other connection through the metal head and top
suspension to the coil; the two plates or the plate and tube being attached to a suitable
piece of hard wood or other insulating material, and having each a suitable terminal
or binding screw to attach wires to in the usual way. In the vertical forms the magnet
and coil are encased in a suitable box with a glass front and a tube of metal glass or
other material is employed to protect the suspension between the head and the box
before mentioned, in the horizontal forme the case may be cylindrical or any suitable
shape. The coil I mount on a complete frame of metal, such as Iron to damp the
swing of said coil, or I may wind the coil with insulated iron wire to give it a directive
action of its own in which case 1 suspend the coil by a silk fibre unspun or on a point
in a jewelled centre in the usual way, in the later case I do away with the top head

page_text: and suspensions and reduce the size of the instrument, or I may arrange the coil to
have two or more circuits and cause a constant current to flow through one of them
to give the coil directive action and cause it to come to zero and the current to be
measured through one or more of the other circuits, in this case also doing away with
the top head and suspensions, making the connections by means of mercury cups of
peculiar construction. I make the cup of larger size than usual for the purpose and
well amalgamate the inside up to almost the top. I provide an inverted cone piece
fitting tightly into the top of the mercury cup, this cone is small at the bottom and
tapered inside and out to be about one uniform thickness. I well laquer the inside of
the cone, but the outside that goes opposite the inside wall of the cup I well
amalgamate, by this means when the instrument is tipped over the mercury follows
the amalgamated part into the top of cup instead of falling out. In using the ordinary
instrument with metal suspensions, with a current of any amount passing through the
coil there is a displacement of the coil independent of the turning, this displacement
is due to the current entering at one end of the coil and leaving at the other end in
my improved method with mercury cups this is entirely done away with, the current
entering and leaving at the bottom or top as the case may be, thus the instrument can
he worked with strong currents and if properly wound as a differential galvanometer,
with great ease-This instrument mounted on the flat board or vertical plate is
provided with an attachment for hanging it to the wall to save table space but when
necessary I provide three feet to the bottom. of the box covering the magnets and the
back vertical plate two or all having leveling screws, so that the instrument can be
used either on a table or against a wall, as may be desired. I attach to the instrument
a plumb with weighted end to tell when the instrument is in a vertical position instead
of levels as are usually used for such purpose.
Dah Tand the ML 1007

page_text: COMPLETE SPECIFICATION.
Improvements in Instruments for Detecting and Measuring Electric
Currents.
PHILIP JOLIN of 35 Narrow Wine Street in the city and county of Bristol Electrical
Engineer 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 :-
In instruments commonly called galvanometers as now constructed with a moving
coil on the principle of Thomsons Syphon recorder it is usual to attach the magnet to
a horizontal base by means of brackets and to carry the suspension by suitable pillar
or pillars which also carries the core-a contre piece of soft iron which is inside the
coil to strengthen the field. Now in my improved arrangement I propose to attach
the magnet which may have flat or curved pole or pole pieces directly to a rigid
horizontal or vertical plate or extension thereof, which also carries the centre core,
which I make preferably of a compound magnet to strengthen the field. I carry the
lower suspension by a suitable spring carried by this horizontal or vertical plate,-in
the vertical form the suspension may be lengthened by drilling a hole through the
neutral part of the magnet and allowing the suspension to pass through it to the spring
aforesaid, the electric connection being made from this said plate through the spring
and lower suspension to the coil. I attach the top suspension to another plate or to a
tube with a suitable metal head capable of a rotary motion around in a horizontal
plane to adjust the coil, or, the magnets themselves and centre core may be adjustable.
I also provide the head with another adjustment to raise and lower the coil-this top
plate forms the other connection through the metal head and top suspension to the
coil the two plates or the plate and tube being attached to a suitable piece of hard
wood or other insulating material and having terminals or binding screws to attach
wires to; or I may so arrange the magnets that they form a frame in themselves and
at the top attach a block of metal to carry the head aforesaid.
In the vertical form the magnets and coil are encased in a suitable box with a glass
front and a tube of metal, glass, or other material, is employed to protect the suspension
between the head and box aforesaid.
In the horizontal form the case may be cylindrical or any other suitable shape. The
coil I mount on a complete frame of metal such as Iron or I may wind the coil with
insulated Iron wire to give it a directive action of its own in which case I suspend the
coil by a silk fibre unspun or on a point in a centre jewelled in the usual way. In
the latter case I do away entirely with the head and top suspension and reduce size of
the instrument. I make the connection with mercury cups of peculiar kind, I construct
the cup of large size and well amalgamate the inside up to inch of the top 1 provide
an inverted cone piece fitting tightly into the top of the mercury cup this cone is small
at the bottom tapering inside and out to be about uniform thickness and having a
larger opening at the top like a funnel. I well lacquer the inside of the cone but the

page_text: outside that goes opposite the inside wall of the cup I well amalgamate by this
arrangement when the instrument is tipped over the mercury follows the amalgamated
part into top of cup instead of falling out, this general forme is in ordinary use for
ink pots at the present time.
In using the ordinary instrument with a current of any amount passing throngh
the coils there is a displacement of the coil independant of the turning. This
displacement is due to the current entereng at one end of the coil and leaving at the
other in my improved method with mercury cups this is entirely done away with,
the current entering and leaving at the bottom; the instrument can be then worked,
if wound properly, as a differential galvanometer. This instrument mounted on the
flat vertical plate is provided with an attachment for hanging it to the wall to save
table space but when necessary I provide a stout metal plate having three binding
screws or I provide three feet to the bottom of the box covering the magnets and the
hack vertical plate, two having adjusting leveling screws so that the instrument can
be used either on a table or against the wall as may be desired. I attach to the
instrument a plumb with weighted end to tell when the instrument is in a vertical
position in preference to levels as usually used.
To further facilitate the changing of the coils and improve the connections 1
construct the top head with a clip, through which passes the suspension wire or another
wire to which the suspension is soldered and I also hold in the same clip the wire
going direct to one of the terminals; for neatness I cover this clip with a cap. [ also
provide a similar clip to the bottom spring for the same purpose.
That this invention may be more clearly understood I append a sheet of drawings
Figs. 1 & 2 represents respectively the elevation and plan of a vertical instrument
constructed according to my improved method wherein the magnet is made into the
frame to carry the coil and centre compound magnet X. M, M, M, M. is a three leaf
compound magnet of ordinary horseshoe type arranged so that one leaf is at the
bottom and two leaves are outside and at the top thus leaving a space between them
into which at the centre of the top is fitted a block of metal N, which carries the
movable head H, through which head passes the adjusting screw S. this screw has at
its top a clip piece D made of stout metal held to the extension of, the screw by
suitable screws the lower part of the screw S is drilled and the top suspension A
passes up through the hole in centre of screw S and is clipped by tightning the
Screws of D. the wire W is also clipped at the same time and is the extension of
the wire soldered to one of the terminals T (see plan) the top clip is covered by a
suitable cap K the block is held in position between the magnets by the screws C¹, C³,
the magnets are held to the base B, B, by four cocks of metal L, L, L, L, two on each
side of the compound magnet M, M. Studs ce pass through the magnets and nuts n, n
hold the magnets iogether, said nuts being sunk into said cocks L, L, L, L, the cocks
are then placed on the studs, and other nuts P, P, are used to hold the cocks to the
magnets. At the back there is a flat bar of metal e passing also over the ends of the
studs from side to side which carries the centre core a compound magnet X the cocks
being held to base by suitable screws mm mm the lower suspension A' is carried by
the spring which is soldered to the wire of the other terminal T¹ (see plan) this
spring has a clip of metal 1' similar to D in every respect the lower suspension A¹ is
firmly held by this clip in the same way as the top suspension A. The coil E is
wound on a rectangular frame of metal exceedingly thin: this frame acts as a support
to the coil and at the same time assists in damping the oscilations of the coil itself; if
made of a magnetic substance it helps to give a controlling action to the coil's position
in the field the same effect is also produced if the coil is wound with insulated iron
wire. The top of the coil has a metal T piece y to carry the mirror and to attach
ine suspension to, a shorter T piece y' is also provided at the bottom to attach the
lower suspension to; the base has usually three levelling screws R, R, R, attached as
shown; the instrument being covered by a suitable glass shade having a hole drilled
in the top and another in the side in which a piece of plate glass A is inserted to
allow the beam of light from the mirror to pass uninterrupted to the scale.
The vertical wall pattern is shown in elevation in Fig. 3 and in plan in Fig. 4.

page_text: Similar letters refer to similar parts, the base B is vertical and to it is attached the
plate of metal Q carrying the head block N with head H and screw S and clip D as
Fig. 1 but in this case covered by the cap K this is attached in the same way to
terminal T by a wire W the compound magnet in this case a "Jarmins" is fixed to
the plate by a clip plate U with screws, , in the usual way-the centre X is also
screwed to the plate Q by the screw X the neutral point of M is drilled to allow the
suspension A¹ to pass through to the spring F also attached to plate Q the spring being
in immediate connection with terminal T through plate Qitself. The coil is the same
as Fig. 1 and the top suspension is protected by a glass tube Z. A plate Y is provided
at the top to hang this instrument to the wall and levelling screws R, R, R, screwed
into a stout metal plate R' are provided when the instrument is for table use; the
lower part of the instrument is enclosed in a case of suitable shape L2 L2 L2 L2 having
a glass sliding front w. A plumb V with weighted end is fixed at the side to tell when
the instrument is in a vertical position.
I
The horizontal instrument is constructed on a suitable base B as shown in elevation
and plan Figs. 5 and 6 respectively. B. B is the base and B₁ the, extension to which
is screwed the horizontal magnets M the top of the extension B₁ also carries a
cock B to which is screwed the center piece X the lower suspension is exactly the
same as in Figs. 1, 2. 3 and 4 except that it is found most convenient to insulate the
spring from the case the top dial D is carried by a suitable frame C³ ³ ³ attached
to the base B and the tube Z of metal is attached to the dial or an independant pillar
from the base B, this tube carries the top head H and screw S with clip D as
Figs. 1 & 2 I also provide an adjustment of the magnets and core around the centre
of the said core in a horizontal plane when the coil has a directive action given to it:
this adjustment is for the same purpose as the adjustment of the head H to bring the
pointer Por spot of light to zero. The coil will of course take up a certain definite
position in the field, due to the directing action of the coil and by moving the field
around its centre the coil can be brought so that the pointer will stand at zero.
may use a pointer P' of any light material instead of a mirror if desireable, suitable
arrangements of case and scale being made. I arrange the head shown enlarged in
Fig. 11 which has a rotary motion and is held in its place by means of pins ss
passing through the metal block N and across a groove g in the lower part of the said
head which groove allows head to turn but not to be pulled out, owing to the pins
The Figs. 9 & 10 show plan and section of the screw S with its extension S and clip
piece D held together by the screws 79; said screw S having hole H drilled as before
mentioned for suspension A. To raise and lower the coil I insert a tommy into the
hole n' of screw S and turn the head H until the coil is in the desired position, the
turning of the head screwing the screw S in or out as the case may be, or the screw S
may be held in the fingers. I provide in the horizontal form a short circuiting
key J, J attached to the base B and connected by wires jj¹ to the terminals by which
I can on pressing down the spring J short circuit the coil and bring it to rest
immediately if necessary; this is most useful when large deflections are taken. To
wind the instrument differentially I use a double wire composed of two wires twisted
together before winding on the coil. Figs. 7 & 8 show side and front views of the
centre metal frame on which I wind the coils E the bottom of the grove of the frame
is shown by e and the sides or flanges by hh. Fig. 12 shows plan of a Resistance box
or Wheatstone Bridge for testing purposes with one of my improved galvanometers /
preferably of the type Figs. 5 & 6 mounted in the centre of the metal ring-bar r, r
which carries the plugs for the resistance coils in the usual well known way: p is the
pointer, the suspensions are kept of suitable length by deepening the case aa aa a
which is a travelling case with hinged or other suitable lid a space may also be
provided at the side to carry a battery. A considerable advantage is obtained by means
of my clipping device in the head as not only do I get a good and reliable contact but
I am also able to readily remove one coil and to replace it by another with great ease
and certainty which was not possible in the old method of soldering the suspension
wire to the screw S.

page_text: 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
1st. In Electric measuring instruments with a moving coil and permenent magnetic
field the use of a permenent magnetic centre core substantially as described and shown
in Figs. 1, 2, 3, 4, 5, & 6.
2nd. In Electric measuring instruments with moving coil the use of an adjusting
head with screw and clip plate substantially as described and shown in Figs. 9, 10,
& 11.
3rd. In Electric measuring instruments with moving coil the construction of the
coil on a framing of any metal substantially and for the purpose described.
4th. In Electric measuring instruments the use of the permenent magnets therein
contained for supporting the top suspension and centre core substantially as described
and shown in Figs. 1 & 2.
5th. In Electric measuring instruments with permenent magnetic field and moving
coil, the arrangement of the field magnets centre core and head on suitable plate or
plates substantially as described and shown in Figs. 3 & 4.
6th. In Electric measuring instruments as described the mode of suspending
against a wall substantially as described and shown in Figs. 3 & 4 or modification
thereof.
7th. In Electric measuring instruments the arrangement of the outside magnets
and centre core with coil and suspension substantially as described and shown with
relation to Figs. 5 & 6 or any modification thereof.
8th. In Electric measuring instruments the use of a short circuiting key
substantially and for the purpose described.
9th. In Electric measuring instruments with moving coil and permenent magnetic
field the method of moving the field around its centre substantially and for the purpose
described.
10th. The combination of an Electric measuring instrument such as shown in
Figs. 5 & 6 or any modification there of with a suitable resistance box as shown in
Fig. 12 substantially and for the purpose described.
11th. In Electric instruments the use of mercury cups with inverted cone centres
to prevent spilling of mercury substantially as set forth and described.
12th. In Electric measuring instruments with moving coil the method of taking in
the electric current and allowing it to pass out at the bottom of said coil substantially
and for the purpose set forth.
Dated this 21st day of December 1877.