Year: 1887

page_text: We, WILLIAM HARDING SCOTT, and EDWARD ALEXANDRE PARIS, both of Gothic
Works, King Street, City of Norwich, in the County of Norfolk, 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 relates to a simple construction of magnetic cut-out, designed upon
any increase of current over the normal to break the circuit.
In order that our invention may be the better understood, we now proceed to describe
the same in relation to the drawings hereunto annexed, in which like letters refer to
like parts throughout the figures.
Figure 1 represents our device in front elevation with circuit broken.
Figure 2 represents the same in side elevation with circuit complete.
Figure 3 shows a detail.
The current is led from a contact A round the core B, which forms a magnet, thence
to the contact C, which leads the current through a mercury cup across the pivotted
bridge piece D into a second mercury cup, and thence throughout the circuit. The
bridge between the mercury cups is pivotted at E, and an armature F, pivotted at G,
is provided with a detent H, which normally holds the bridge in position and keeps
the circuit complete, as in Figure 2.
Now, upon any increase of current through the coil of the electro magnet, the
armature is attracted thereto, the detent releases the pivotted bridge piece, and it falls,
withdrawing the contact fingers from the mercury cups and thus breaking the circuit,
as in Fig. 1. Figure 3 shows a detail of the two mercury cups insulated one from
another. The distance of the armature from the pole piece of the magnet, and
thereby of the force requisite to move same, is adjustable by means of the screw K.
A small extra terminal L may be provided, connected to the main conductor. In
incandescent lamp circuits a lead from one or more lamps might be connected to this
terminal L, the other lead being connected to the terminal M. This lamp would be
short circuited when the main circuit was complete, but when the main circuit
is broken, the lamp or lamps would be in circuit and the current would pass
therethrough in place of through the pivotted bridge in the mercury cups, and

page_text: would indicate by the comparative brightness or dulness of the lamps the nature of the
cause which had brought the cut-out into action.
Further, by means of this extra terminal and auxiliary circuit any resistance
might be automatically brought into action, such resistance being short circuited
when the pivotted bridge is held up and brought into action when it falls.
Further a small fuse N might be inserted between the cut-out conductor and the
small extra terminal.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what we
claim is :-
1st. In a magnetic cut-out, the combination of an electro magnet with a pivotted
adjustable armature normally holding a bridge piece completing the circuit, but
which on excess current causing the magnetic force to attract the armature, thereby
allows the bridge to drop and the current to be broken, substantially as and for the
purposes specified.
2nd. The combination with such a device of an auxiliary circuit containing a lamp
or lamps or resistance, substantially as and for the purposes described.
3rd. The combination with our device of an auxiliary circuit and a safety fuse,
substantially as and for the purposes described.
Dated
Imay 2001.
FELL & WILDING,
1, Queen Victoria Street, London, E.C.,
Agents for the Applicants.
FELL & WILDING,
1, Queen Victoria Street, London, E.C.,
Agents for the Applicants.