Automatic Electric Switch.
Year: 1893

page_text: Date of Application, 16th Dec., 1893
Complete Specification Left, 13th Sept., 1894-Accepted, 1st Dec., 1894
Automatic Electric Switch.
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 invention is an automatic switch for the purpose of joining together two
circuits A & B when the electro-motive force of A is a predetermined amount in
excess of and opposed to that of B, and disconnecting them when the electro-
motive force of A is in the same direction as that of B; or opposed to and equal
to it, or less than it by any predetermined amount.
We join the (say) + end of the A circuit to the + end of the B circuit direct,
and the minus ends of the two circuits through the coils of an electro-magnet
(say C).
We also excite an electro magnet (say D) of sufficiently high resistance direct
from the whole or a part of B circuit and place it with its north pole against
the pole of the first magnet, which is made north when the current flows from A
to B and vice versa (or for north read south in both cases).
When the electro-motive force of A is greater than that of B, the poles of the
two magnets therefore tend to repel one another and vice versa.
By suitably pivotting one of the magnets we cause it when repelled, to elose a
mercury or other switch or to actuate any convenient mechanism and thereby
connect A on to B direct.
This generally causes the electro-magnet D to lose it's exciting current, and
we therefore carry the main current which then flows from A to B through an
auxiliary coil round the core of C, magnetising it and causing it to act in the same
way as before.
Should the current stop or a reverse current flow, the two poles attract one
another and the connection between A & B is broken.
We generally arrange the instrument so that when no current is acting, the
automatic switch is broken by gravity or otherwise.
Instead of pivotting the whole electro-magnet we sometimes pivot the core only
and make the internal bore of the exciting coils so large that the core is free to
move inside them.
We do not confine ourselves to pivotting, but may make the electro-magnet or
core moveable in any other way, such as hanging it from an arm or beam, or we
may make both magnets or their cores moveable.
We may use the instrument for joining up cells to a dynamo to be charged.
or for connecting dynamos to supply-leads when they reach their proper electro-
motive force, or any similar purpose.
Dated this 16th day of December 1893.
Per pro F. H. NALDER,
Herbert Nalder.
HERBERT NALDER.
C. W. S. CRAWLEY.
ALFRED SOAMES.

page_text: Automatic Electric Switch.
F
We FRANCIS HENRY NALDER of 16 Red Lion Street, Clerkenwell, in the
County of Middlesex, Electrical Engineer, HERBERT NALDER of "Coniston
Foxgrove Road Beckenham in the County of Kent, Electrical Engineer, CHARLES
WILLIAM SCOTT CRAWLEY and ALFRED SOAMES 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 invention is an automatic switch for the purpose of joining together two
circuits A & B when the electro-motive force of A is a predetermined amount in
excess of and opposed to that of B, and disconnecting them when the electro-motive
force of A is in the same direction as that of B; or opposed to and equal to it, or
less than it by any predetermined amount.
-
We join (say) the end of the A circuit to the end of the B circuit direct,
and the plus ends of the two circuits through the coils of an electro-magnet
(say) C..
We also excite an electro magnet (say D) of sufficiently high resistance, direct
from the whole or a part of B circuit, and place it with its north pole against the
pole of the first magnet C which is made north when the current flows from A to B
and vice versa (or for north read south in both cases).
When the electro-motive force of A is greater than that of B, the poles of the
two magnets therefore tend to repel one another, and vice versa.
By suitably pivotting one of the magnets we cause it when repelled to close a
mercury or other switch or to actuate any convenient mechanism and thereby
connect A on to B direct.
This generally causes the electro-magnet D to lose it's exciting current, and we
therefore carry the main current which, then flows from A to B through an
auxiliary coil round the core of C magnetising it and causing it to act in the same
way as before.
Should the current stop or a reverse current flow, the two poles attract one
another and the main connection between A & B is broken.
We generally arrange the instrument so that when no current is acting, the
automatic switch is broken by gravity or otherwise.
Instead of pivotting the whole electro-magnet, we sometimes pivot the core only,
and make the internal bore of the exciting coil so large that the core is free to
move inside it.
We do not confine ourselves to pivotting, but may make the electro-magnet or
core moveable in any other way, such as hanging it from an arm or beam, or we
may make both magnets or their cores moveable.
We may use the instrument for joining up cells to a dynamo to be charged, or
for connecting dynamos to supply leads when they reach their proper electro-motive
force, or any similar purpose.
Fig. 1 of accompanying drawing is an elevation, and Fig. 2. a plan of con-
struction of an instrument to carry out the above invention,-like letters apply to
like parts in all figures.
F is the core of an electro-magnet energised by two coils C & E.
D is another coil which energises a core G which is pivotted at H and carries
rigidly attached to it an arm J having a fork K K which can dip into and short
circuit the two mercury cups L L.
M is a weight for adjusting the balance of the moving part, and M 1 a weight for
lowering it's centre of gravity.
NNIN are terminale

page_text: The weight M requires to be adjusted so that when neither of the magnets are
energised & hangs over towards F and the fork K lifts out of L L.
From the above description it will be seen that G is magnetised by the current
from B the upper end being made say north.
When the electro-motive force of A is less than that of B a current flows from A+
round C to B+; the coil C being wound so that this current makes the lower end
of F south, (or opposite to that of the upper end of G as above).
F & G therefore tend to attract one another.
When however the electro-motive force of A is greater than that of B the current
flows round C in the opposite direction, making F north, and thus tending to
repel G.
M is now adjusted so as to counteract this repulsion and prevent G moving until
the electro-motive force of A exceeds that of B by a predetermined amount (it will
be seen that this setting of M fulfils the previous requirement).
G is now repelled from F thus joining L L by K, thus completing the charging
circuit through the auxiliary coil E.
The coil E is wound so that the charging current keeps the lower end of F
south.
When the current in E becomes small the weight M breaks the charging circuit,
through the coil E. If K is accidentally depressed by hand or otherwise, when the
electro-motive force of A is less than that of B a reverse current will flow through E,
and G will be attracted to F and the charging circuit through the coil E will be
at once broken.
It will be seen that if any coil breaks down, it's core being no longer magnetised
by it, there is at once attraction between it and the other core, instead of repulsion,
and the main circuit through the coil E thereby broken.
We do not confine ourselves to the precise form here shown, but may use any
suitable modifications thereof. For example: We sometimes, instead of the
mercury contacts, use a switch of any convenient form, actuated either directly or
through a relay, in any well known way. We sometimes use solenoids instead of
electro-magnets especially when working with alternating currents.
Instead of the straight magnet F we may use any convenient shape, such as
that shewn diagramatically in Fig. 3.
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 automatic switch for the purpose mentioned the combination of two
electro-magnets or solenoids repelling each other to join the circuits, and attracting
each other to break the same.
2. The instrument substantially as described.
1
T
1004
C. W. S. CRAWLEY.
ALFRED SOAMES.
F. H. NALDER.
HERBERT NALDER.