Improvements in Apparatus for Automatically Cutting Out Electrical Currents from Dynamos when Rising Above or Falling Below a Determined Maximum or Minimum, and for Gradually Turning On such Currents.
Year: 1897

page_text: Date of Application, 24th Feb., 1897-Accepted, 27th Mar.,
1897
COMPLETE SPECIFICATION.
Improvements in Apparatus for Automatically Cutting Out
Electrical Currents from Dynamos when Rising Above or
Falling Below a Determined Maximum or Minimum, and for
Gradually Turning On such Currents.
I, EDWARD LIONEL JOSEPH, of 92, Queen Victoria Street, in the City of
London, Electrical Engineer, do hereby declare the nature of this invention, and
in what manner the same is to be performed, to be particularly described in
and by the following statement, and accompanying drawings, that is to say :-
My invention relates to apparatus to be used in the main conducting circuit.
from electrical dynamos, and it has for its object a novel method of constructing
such apparatus, so that if the current exceeds a certain predetermined maximum it
is automatically cut off, and if it falls below a certain minimum it is also
automatically cut off, both operations being effected by means of the same
instrument. Also, of means whereby the current when turned on is supplied
gradually instead of suddenly, the apparatus for effecting this being also contained
if desired in the same instrument.
It is important in many cases where a "dynamo" is used for supplying electric
current for accumulator cells or for other purposes, that if the current so supplied
exceeds a certain defined maximum, the circuit should be automatically broken by
means of what is known as a "cut-out," so that the current is no longer supplied.
Similarly, when for example accumulators are being charged by the dynamo, if
the current falls below a certain minimum, the circuit is also automatically broken,
instrument has
" cut-out
A separate
by a "cut-out of a similar kind.
ordinarily heretofore been used for each purpose; and two kinds of such instruments
have been used, in one of which the cutting-out is effected by the withdrawal of
conducting terminals from mercury cups into which they dip and through which
the current passes, whilst in the other the cutting-out is effected by breaking the
metallic contact of contact-pieces through which the current
"
passes.
"
are
By my present invention hoth the maximum and the minimum "cut-out
contained in the same instrument, and advantage is gained in simplicity, convenience,
and efficacy, whilst by the method of construction which I use a larger carrying
capacity for current than usual through the conducting bridge is readily
attainable.
The accompanying drawings are in illustration of my invention, Figure 1 being
a front view of the apparatus when the current is cut off, and Figure 2 being a
similar view when the full current is passing through the conductor.
Figure 3 is a side view of Figure 1 from below, and Figure 4 is a view of
Figure 1 from above.
a is a foundation plate, preferably of enamelled slate, or other suitable non-
conducting material which is screwed upon wooden or other convenient supports b.
A handle c is attached to a central pivot turning in or on a bearing at d in the
plate a, and having attached to it a metallic bridge e forming an electrical conductor

page_text: and preferably made of separate plates (as shown in Figures 3 and 4) so as to
give it considerable elasticity, its ends being turned inward, as shown at, so that
they press with sufficient elastic force upon the surface of the contact piece g at
one end, and upon one or other of the contact pieces h, h', h2, and 3 at the other
end, (when the handle is turned into the position shown in Figure 2). A coiled
or other spring i tends always to bring the handle c and conducting bridge e into
the position shewn in Figure 1 (where the current is cut off), and k, k', are fixed
stops against which the bridge e is brought by the spring, preferably with the
intervention of springs by which sudden shocks are prevented. A metallic
coil m is carried by the insulated supports n, n', fixed to the plate a, one end of
the coil m being connected by a conducting plate o (under the plate a) with the
contact piece g, and the other end of the coil communicating with the attachment p
to which the main conducting wire is attached, the other end of the conducting
wire being attached to a similar attachment p¹ communicating with the contact
piece. A soft iron. insulated core is contained in the coil m, being carried by
the support m', and its ends project slightly through the supports m', n.
.c is a
An armature s turns freely upon a pivot t in a support u, which also carries a
regulating screw by which the movement of the armature is limited, and w is an
adjustable weight upon the outer part of the armature, by which the effective
attractive force of the soft iron core r upon it can be regulated as desired.
bracket or support fixed to the plate a and having at its outer end guides in which
slides freely up and down a spindle y which is constantly pressed down by a
spring. This spindle passes freely down between the arms of a fork at the end
of the lever s, and carries at its lower end a freely revolving disc or roller 2.
When the armature is attracted by the soft iron core r, its other end lifts
the spindle y and roller 2, by means of a collar or pin 3 upon the spindle. The
conducting bridge e carries a plate 4 the outer end of which is formed at 5 as the
segment of a circle struck from the centre d, and in the outer edge of this segment
are formed curved notches A, A', A2, A3, (any desired number of which may be
used) into which the disc or roller 2 drops in succession, as the segment passes
under it when the handle c is turned.
The notch A is entered by the roller 2 when the conducting bridge is in
contact with the contact piece h, the notches A1, A2, A3, when it is in contact with
the contact pieces 1, 2, 3 respectively, and the spring 2 is sufficiently strong to
cause the roller 2 to retain the conducting bridge in either position until the roller
is raised.
A resistance or resistances of the usual well-known kind, (not shown in the.
drawings) is arranged in connection with the contact pieces h, h¹, h² and h³, in such
manner that when the conducting bridge e is in contact with h only a small part
of the current passes through it, the amount of current increasing progressively
through the contact pieces h¹, h2, until the entire current passes when the bridge e
has reached, and the current can therefore be gradually, instead of suddenly,
switched on when the handle c is gradually turned from the position shown in
.Figure to that shown in Figure 2.
If now the apparatus is in the position shown in Figure 2, the full current being
passing through p, m, o, g, e, h³, p¹, then if the current exceeds a certain maximum
(determined by the position of the weight w) the armature s is attracted sufficiently
to raise the weight w and the roller 2, against the pressure of the spring, and the
segment 5 is released, the spring bringing the conducting bridge e and the
handle c into the position shown in Figure 1, the current being thus automatically
cut off.
In order that the current may likewise be automatically cut off in the same way
if it falls below a certain minimum, I use a vertical spindle 6 working freely up
and down in guides 8, parallel to the coil m.
The upper end of this spindle 6 passes freely through a fork at the end of the
armature s, and is provided with a knob 7 of sufficient weight, which when the
spindle is at its lowest position presses down the armature.

page_text: The lower end of the spindle 6 bas fixed upon it.a transverse soft iron armature B
the outer end of which guided upon guides 9.
A knob or handle 10 is fixed upon the spindle 6 below the other end of the.
armature, and can be used to raise by hand the armature 8, spindle 6, and
knob 7, until the armature B is close to the lower projecting end of the core r,.
its exact distance from which however can be adjusted and regulated by a brass
screw 11.
When the full current is passing through the coil m, the armature B and
spindle 6 are raised (as shown in Figure 2), the screw 11 being so adjusted that
the armature is kept raised by the attraction of the core r. If however the
current falls below the determined minimum, the attraction is no longer sufficient
and the weight 7 brings down the armature B and spindle (as shown in Figure 1),
and strikes the armature s raising the roller 2 and releasing the conducting
bridge e and handle c, which fly back into the position shown in Figure 1, in the
manner already described when the current is too great. 12 is a spring which.
prevents too great shock when the weight 7 falls.
Where shunt wound field magnets are used in the dynamo, it is advisable that a
current should be passed through them slightly before the current is passed through.
the first of the contact pieces h. In such case I prefer to use a separate contact
piece 9', against which a supplementary arm e¹ of the conducting bridge e is
brought in contact (as shown in Figure 2) a little before the main conducting
bridge e comes in contact with h, the conducting wire to the shunt coil being
connected with g'.
Figure 5 shows in front view an apparatus for the same purpose as that already
described but smaller and of a simpler kind, the resistances and device for enabling
the current to be supplied gradually instead of instantly being omitted. The same
letters of reference indicate the same parts. In this form of apparatus the plate
carried by the conducting bridge e has only one notch or recess A to receive the-
roller 2, which comes into operation when the conducting bridge is in contact with
the single contact piece h. The springs upon the conducting bridge e are
omitted, and the connecting piece is shown above the plate a, instead of
below, the remainder of the apparatus being substantially the same as that first.
shown.
0
In both forms studs or stops may be used where necessary, to limit the movement
of the moving parts of the apparatus.
I do not confine myself to the precise details of construction and arrangement,.
which may be varied more or less to suit the varying circumstances and conditions
in which the apparatus is to be used, but
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
1. The combination in a single instrument of a cut-out automatically breaking
an electric current circuit when a predetermined maximum of current is exceeded,.
and automatically breaking the said current circuit when the current falls below a
predetermined minimum, substantially as described.
2. For the purpose of carrying out the first claim the combination in the instru-
ment of the handle c turning on the centre d, the conducting bridge e, contact
pieces 9, 9, spring i, insulated coil m, core r, pivotted armature 8, adjustable
weight w, spindle y, spring z, roller 2, collar or pin 3, segment plate 4, 5, notch A,.
spindle 6 weight 7, armature B, adjusting screw 11, and connections o, p, p, all
arranged and operating substantially as described and illustrated in Figure 5 of
the accompanying drawings.
3. In combination with the apparatus described and claimed in Claims 1 and 2,
the devices for turning on the electrical current gradually instead of instantly,
consisting of the segment plate 5 carried by the conducting bridge e, notches A, A',.
A³, A³, to receive the roller 2, the separate contact pieces h, h¹, h³, 1³, and an.

page_text: electrical resistance or resistances, connected with the contact pieces h, h¹, h², h³, in
such manner that the current passing through the conducting bridge e is increased
by degrees, all substantially as and for the purpose described and illustrated in
Figures 1, 2, 3, and 4 of the accompanying drawings.
Dated this 22nd day of February 1897.
EDWARDS & Co.,
65 and 66, Chancery Lane, London, Agents for the Applicant.