Improvements in Electrical Measuring Instruments.
Year: 1893

page_text: Date of Application, 28th Dec., 1893
Complete Specification Left, 28th Sept., 1894-Accepted, 15th Dec., 1994
PROVISIONAL SPECIFICATION.
Improvements in Electrical Measuring Instruments.
We, FRANCIS HENRY NALDER, HERBERT NALDER, CHARLES WILLIAM
SCOTT CRAWLEY, and ALFRED SOAMES, all of 16 Red Lion Street, Clerkenwell
in the County of Middlesex, Electrical Engineers, do hereby declare the nature of
this invention to be as follows:-
Our instrument consists of a pivoted coil or loop conveying a current moving in
a field of force.
We convey the current to the moving coil either by means of springs pressing
on to the ends of the pivots, which work in collar or other bearings, or we may
attach the bearing on to the springs themselves, or we may pivot the coil in
ordinary jewel or other bearings, and rigidly attach springs to the coil; the other
ends of which springs press on contacts, preferably in the axis of rotation of the
coil.
In all these cases we, instead of using two springs connections, may use one such
spring connection, pressing the other connection of the coil against a contact.
The parts between which a moving contact is made may be of any suitable
metal, but we prefer to use platinum iridium or similar incorrodible metal.
We usually control the movement of the coil by rigidly attaching to it a piece,
or pieces, of soft iron or other paramagnetic material, magnetised by the field of
force, and preferably saturated by it, so as to avoid or minimise any error due to
change of the field of force, or we may use gravity, or spring control, or other well
known form of control, or any continuation of two or more of the above methods.
We sometimes shunt the coil and connections to minimise sparking.
Dated this 28th day of December 1893.
FRAS. H. NALDER.
HERBERT NALDER.
C. W. S. CRAWLEY..
ALFRED SOAMES.
COMPLETE SPECIFICATION.
Improvements in Electrical Measuring Instruments.
We, FRANCIS HENRY NALDER, HERBERT NALDER, now of "Coniston,"
Beckenham Kent, CHARLES WILLIAM SCOTT CRAWLEY, and ALFRED SOAMES,
all of 16 Red Lion Street, Clerkenwell, in the County of Middlesex, Electrical
Engineers, 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 instrument consists of a pivoted coil or loop conveying a current moving in
a field of force.
We convey the current to the moving coil either by means of springs pressing
ou to the ends of the pivots, which work in collar, or other bearings, or we may
ID011

page_text: attach the bearings on to the springs themselves, or we may pivot the coil in
ordinary jewel or other bearings, and rigidly attach springs to the coil; the other
ends of which springs press on contacts, preferably in the axis of rotation of the
coil.
In all these cases, we, instead of using two springs connections, may use one
such spring connection, pressing the other connection of the coil against a contact.
The parts between which a moving contact is made, may be of any suitable
metal, but we prefer to use platinum-iridium, or similar incorrodible metal.
We usually control the movement of the coil by rigidly attaching to it a piece
or pieces, of soft iron or other para-magnetic material, magnetised by the field of
force, and preferably saturated by it, so as to avoid or minimise any error due to
change of the field or force, or we may use gravity, or spring control, or other
well known form of control, or any combination of two or more of the above
methods. We sometimes shunt the coil & connections to minimise sparking.
Fig. I shows a sectional front-elevation. Fig. Il a sectional side elevation,
Fig. III a front elevation. Fig. IV the needle system of a construction of an
instrument for carrying out the above invention.
Like letters apply to like parts in all figures.
A is a permanent magnet fixed to the base B, and covered by a cover C.
Between the poles of A is a coil D. working on pivots E E. in bearings R. R.
carried by the brackets S S and preferably balanced about its axis. The ends
of D are joined to the springs F F which press on the contact-points G G which are
attached in the axis of rotation to the insulated cores H H which are electrically
connected to the terminals L L either directly or through resistance coils M. M.
N is a magnet attached to the coil D. O is a pointer also attached to D working
over a scale P.
From the above description it will be seen that the coil being balanced & freely
pivoted takes up a position across the poles of A A. When a current passes
through D it tends to set it at right angles to the field of A A against the control
of the inagnet N, thus deflecting the pointer over the scale l' an amount
depending on the amount of current passing through D.
We sometimes use an electro-magnet or coil or other well known means of
producing a field of force. We sometimes attach the spring to convey the current
to the coil to the bracket and have the points on which they make contacts on the
coils, as in diagram Fig. V, or we sometimes attach the bearings in which the coil
rotates to the springs themselves, and make contact through metallic endstones or
collars thereof, or both, as in Fig. VI.
Having now particularly ascertained and described the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is
1. In an electrical measuring instrument consisting of a coil or loop conveying
a current moving in a field of force, a spring or springs attached to the coil
pressing on fixed contact points, in the axis of rotation to convey the current, to
the coil.
2. In an electrical measuring instrument consisting of a coil or loop conveying
a current moving in a field of force, a fixed spring or springs pressing on a point
or points attached to the coil in its axis of rotation to convey the current to the
coil.
3. In an electrical measuring instrument consisting of a coil or loop conveying
a current moving in a field of force, a spring or springs carrying the bearings of
the coil, and conveying the current to it through metallic endstones or collars,
or both.
4. The combination of any of the above claims with either spring gravity or
magnetic control or any two or more of them.
5. The combination of any of the above claims with the use of platinum-iridium
or other incorrodible metal for the contacts.

page_text: 6. The combination of any of the above claims with a shunt across the coil and
connections to minimise sparking.
7. The instrument, substantially as described.
FRAS. H. NALDER
C. W. S. CRAWLEY.
ALFRED SOAMES.
HERBERT NALDER.