Improvements in Electrical Measuring Instruments.
Year: 1894

page_text: Date of Application, 26th Nov., 1894
Complete Specification Left, 26th Aug., 1895-Accepted, 2nd Nov., 1895
PROVISIONAL SPECIFICATION.
Improvements in Electrical Measuring Instruments.
GUSTAV BINSWANGER, Electrical Engineer, and EDWARD STANLEY Electrician,
both of 71 Queen Victoria Street, in the City and County of London, do hereby
declare the nature of this invention to be as follows:-
Our invention relates to improvements in electrical measuring instruments, and
has for its objects the elumination of errors in indication due to residual magnetism,
without reducing the mass of iron or magnetic substance used in operating the
index, and also the arrangement of the instrument in such a manner that the scale
for reading indications may be extended in any required part and the length of
said scale may be adjustable, and also its position relatively to the dial plate, such
adjustment being rapidly effected when desirable.
In carrying our invention into effect, for the purpose of constructing a voltmeter
or an ampère meter, the movement of the index pointer is produced by the
magnetic action of the electric current passing around the coils of a suitably wound
solenoid, upon an iron disc sector, fixed upon a pivotted spindle placed parallel to,
or upon the axial line of said solenoid, so that it may revolve in a plane approxi-
mately parallel to its diameter, and normal to the axis of the solenoid. Inside the
solenoid we rigidly fix two blocks of iron or other magnetic substance, the faces
whereof are parallel one to another and between which the disc sector aforesaid is
free to revolve. The disc sector actually corrects the errors due to residual
magnetism, because the area is at the minimum in the direction of the lines of
force, and correspondingly greater in the direction which is normal to the magnetic
field.
When the index is at zero, the sector is just within the space between the
two blocks aforesaid, and when the solenoid is energised by the electric current,
the effect is to cause said sector to enter said space, thus tending to complete
the magnetic circuit.
We may control the movement by gravity, or by means of a spring, either in
tension or torsion; in the latter case the maximum effective range of the instrument
may be extended to 180°, while in the former case the range is necessarily limited
to about 120°. By this method of construction we are enabled to produce an
instrument in which the errors of indication due to residual magnetism are
rendered negligible, without reducing the magnetic mass to such a degree as to
weaken the action, hence in such instruments according to our invention extremely
delicate pivotting and posing is not necessary.
We may control or adjust the scale as aforesaid either by varying the thickness
of the iron disc sector, (the shape being determined by experiment, in order to
fulfil the conditions of various cases of adaptation) or by altering the initial position
of said sector relatively to the space between the fixed blocks.
It is not absolutely necessary that the moving parts actuating the index should
be placed inside the solenoid, as herein before described, since in the case of
instruments having large dials and correspondingly long indices, the force acting
upon the index may be amplified by increasing the mass of iron or other magnetic
substance in the direction of the magnetic lines of force so as to afford a complete
or approximately complete circuit, except in the space which the disc sector
swings, and it is then more convenient to suspend said sector in a gap outside the
solenoid.

page_text: We may apply our said invention to recording ampère and voltmetres, and also
may adapt them for use with alternating electrical currents by suitably laminating
the iron or other magnetic masses, and arranging the bobbin of the solenoid to
conform therewith.
تيمم
1
FREDK. WALKER,
73 St. Stephen's Road, Upton Park, E.,
Agent for the Applicants.
Improvements in Electrical Measuring Instruments.
We, GUSTAV BINSWANGER Electrical Engineer, and EDWARD STANLEY
Electrician both of 71 Queen Victoria Street in the City and County of London
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:―
Our invention relates to improvements in electrical measuring instruments, and
has for its objects the elimination of errors in indication due to residual magnetism,
without reducing the mass of iron or magnetic substance used in operating the
index, and also the arrangement of the instrument in such a manner that the scale
for reading indications may be extended in any required part.
In order that our invention may be the better understood we have appended the
accompanying sheet of drawings in which
Figure 1 is a sectional elevation of the solenoid and movement of either an
ampère meter or a voltmeter, and
Figure 2 is an end elevation of the bracket and iron blocks.
Figure 3 is a plan showing the position of the disc sector and irons when the
index is at zero.
Figures 5, 6 and 7 show how variations in the disposition of the scales are
obtained by varying the taper and relative position of the disc sector.
Figure 9 is a sectional elevation of a modification of the arrangement of the
solenoid and movement.
Similar letters of reference are used to indicate corresponding parts throughout
the several views.
In carrying our invention into effect for the purpose of constructing an ampère
meter or a voltmeter we employ a solenoid S suitably wound, inside which is fixed a
frame F supporting a pivotted spindle A carrying an index P and an iron disc
sector D. The frame has rigidly fixed to it two blocks of iron II' with a gap g
between them, the faces of said iron blocks upon either side of the gap being
parallel to each other as shown on the drawing. The iron sector D is placed upon
the spindle A in such a manner that it may freely move within the gap g.
It is a special feature of the instruments made according to our invention that
all the parts are balanced separately and independently of each other, the control
being wholly maintained either by an adjustable weight W, or a suitably arranged
spring. We fix to the spindle a weight B which exactly balances the disc
sector D, and also balance the index P by means of a piece of metal fixed to it.
Thus, said index P with its counterpoise can be moved round the spindle without
affecting the relative positions of the other parts; viz. the disc sector D and the
irons 11', also we may by moving the controlling weight W round the spindle A
alter at will the relative initial position of the disc sector D with the irons I I'
without causing said weight W to hang out of the perpendicular. This arrange-
nient enables us to obtain the desired disposition of the scale, and also get said

page_text: scale evenly situated upon the dial. Figure 3 shows diagrammatically the positions
of the disc sector D and irons II' when the index P is standing at zero, the
weight W (shown by the dotted outline) standing at zero.
When the electric current passes round the coils forming the solenoid S the disc
sector D moves round its axis in the direction of the arrow, Figure 3 and bridges the
gap g between the faces of the irons II', and so diminishes the path of the magnetic
lines. The variations in the disposition of the scales are obtained by varying the
taper of the thickness of the disc sector D, as shown by Figures 4, 5 6 and 7, and
also by varying the relative positions of D and I in the zero position as shown by
Figures 5 and 64. Figure 5 shows such an arrangement of parts that will enable
a scale to be used, short in the range of reading, but open in its indications and is
suitable for instruments in which the reading is required to commence at about of
the total indication, such as from 80 to 120 and the like. Referring to Figure 5,
it will be seen that the thinnest edge of the disc sector D is foremost entering the
gap g first and said sector D is also arranged so as to be at an appreciable distance
from the irons I when the index is at zero, Figure 5A which prevents it indicating
until about of the total electrical current has passed round the coils of the
solenoid S. Referring now to Figures 6 and 6^ the disc sector D is shown to have
parallel faces and is placed upon the spindle A in such a manner as to be just
entering the gap g between the faces of the irons I I¹ when the index is in the zero
position. This arrangement admits of obtaining a longer range of scale on which
the divisions or degrees of measurement may be evenly spaced. Figure 7 shows
the arrangement of parts necessary to obtain a scale open in its earlier readings
but contracted in the higher readings. In this case the disc sector D is taper, but
is placed relatively to the irons I 1' that the thickest edge is just entering the gap
when the index is at zero.
We may modify the construction of instruments according to our invention by
dispensing with the short iron blocks II' herein before described, and may substitute
therefor a complete or nearly complete magnetic circuit as shown by Figure 8.
This is due to the fact that by the use of a thin flat disc sector we are enabled to
minimise the error caused by hysterisis to such a degree as to allow of a
considerable increase in the mass of the iron in the magnetic circuit.
In this case
the irons II' encircle the solenoid, the frame F carrying the spindle A with the iron
disc sector D moving within the gap 9 outside the solenoid S. This method of
arranging the parts affords a powerful action such as is required for recording
ampère meters and volt meters without increasing the hysterisis error to an
appreciable extent. Any part of the magnetic circuit may be replaced by non-
magnetic material except the faces of the gap in which the disc sector D
works. This arrangement is applicable to instruments having large dials and
correspondingly long indices as well as to recording instruments as aforesaid.
We may adapt instruments made according to our said invention for use with
alternating electric currents by suitably laminating the disc sector and the iron
masses forming the field, and winding the solenoid to conform therewith.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is ;
First. In electrical measuring instruments the construction and employment of a
disc sector, mounted upon a spindle and working in a gap in the iron portion of a
magnetic circuit, in combination with a solenoid, substantially as and for the
purposes herein-described with reference to the accompanying sheet of drawings.
Second. In electrical measuring instruments the methods of, and means for,
obtaining scales having a disposition suited for application to various purposes of
indication substantially as herein described with reference to the accompanying
sheet of drawings.
Third. In electrical measuring instruments the employment of a disc sector
moving in a gap in the magnetic circuit outside a solenoid, for recording the

page_text: variations of current strength or electro-motive force substantially as herein
described with reference to Figure 8 of the appended sheet of drawings.
Fourth. In electrical measuring instruments for measuring or recording the
variations of current strength or electro-motive force in continuous or alternating
electrical circuits the combination of parts substantially as herein described with
reference to the accompanying sheet of drawings.
FREDK. WALKER,
75 St. Stephen's Road, Upton Park, London, E.,
Agent for the Applicants.