Improvements in Electrical Testing Apparatus.
Year: 1890

page_text: Date of Application, 24th Nov., 1890
Complete Specification Left, 23rd Sept., 1891-Accepted, 31st Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in Electrical Testing Apparatus.
REGINALD JOHN JONES of 88 Queen Victoria Street London E.C. Electrical
Engineer, and WOODHOUSE & RAWSON UNITED LIMITED of 83 Queen Victoria
Street London E.C. Electrical Engineers and Contractors, do hereby declare the
nature of this invention to be as follows
-
The invention is intended to produce a testing apparatus which shall auto-
matically come into action at predetermined periods and which shall render evident
the insulation resistance of one or more electrical circuits and if necessary, give
We combine with
notice of such insulation being in an abnormally low condition.
a suitable clockwork electrical devices which shall at predetermined intervals,
connect to earth the middle of two lamps of equal and suitable voltage placed in
series on a circuit whose insulation we wish to test. If the insulation of the circuit
is perfect both lamps glow with equal brilliancy when electrical connection is made
to earth.
We may
We also by suitable arrangement connect each of these lamps separately to
earth by which we may show distinctly on which pole there is a deficient insula-
tion. In the same way we may employ a static voltmeter or electrometer to be
used in connection with the automatic method of making connection.
also combine with this a suitable arrangement by bell or otherwise for giving
notice that the insulation has fallen below a definite amount, or we may combine
with the automatic apparatus a sensitive galvanometer, differentially or otherwise,
We mount the whole
so as to give warning whenever the leakage occurs.
apparatus on a suitable base and provide it with suitable switches and safety
junctions.
البيت
31
1
1000
REGINALD JOHN JONES.
WOODHOUSE & RAWSON UNITED, LIMITED.
George Worrall, Secretary pro tem.
COMPLETE SPECIFICATION.
Improvements in Electrical Testing Apparatus.
REGINALD JOHN JONES, of 88 Queen Victoria Street, London, E.C. Electrical
Engineer, and WOODHOUSE AND RAWSON UNITED LIMITED, of 88 Queen
Victoria Street, London, E.C. Electrical Engineers and Contractors, 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:―
This apparatus is intended to produce a testing apparatus which shall auto-
matically come into action at predetermined intervals of time, and shall render
evident the insulation resistance of one or more electrical circuits, and if necessary
give notice of such insulation being in an abnormally low condition.
To this end we combine with a suitable clockwork, electrical devices, which
shall at predetermined intervals connect to earth the middle of two lamps of equal
and suitable voltage and resistance placed in series on a circuit whose insulation we
wish to test. If the insulation of the circuit is perfect, both lamps glow with
equal brilliancy when electrical connection is made to earth,. between the two
lamps.

page_text: Referring to the accompanying, drawing, which is a plan showing connections,
A is a clockwork arrangement which rotates the drum B, through the spindle Cat
any predetermined speed. The drum Biwhich is permanently connected to earth
by the rubbing contact S, carries three studs which come into contact with the
contact springs consecutively, one stud D makes contact with both of the said
contact springs G and H at the same time, thus connecting them together; the
stand E comes in contact with the contact spring G only; and in the same way F
only comes into contact with the contact spring H. G is connected through an
electro magnet J and an incandescent lamp K and through a fuse N to the positive
of an electric light circuit, and in the saine way H is connected through another
electro magnet L. and an incandescent lamp M, which burns equally bright in
series with the lamp K, and through a fuse Y to the negative pole of the electric
light lead. The electro magnets J and L actuate a tongue O which completes a
local bell circuit R, when touching either of the contacts P or Q
Now to more particularly describe the working of this invention, having
reference to the foregoing, it will be seen that as the drumm B rotates the stud D
makes electrical contact with the contact springs G and H, thus putting the
lamps K and M in circuit in series and at the same time putting the middle of the
lead between the lamps to earth through the contact S. Now if the insulation is
perfect, both lamps will burn with equal brilliancy, but supposing the insulation on
either lead is defective, part of the current through the lamp attached to that lead
will be shunted through the earth and consequently the lamp on that lead will burn
with less brilliancy than the other, also there being more current through one of
the electro magnets or L the tongue O will be attracted to one of the stops P
or Q completing the local bell circuit R and giving warning of the defective
insulation. Then as the drum B continues to rotate, the stud D passes the contact
springs G and H and the leads are tested separately to show distinctly in which.
lead there is a deficiency of insulation the stud E coming into contact with the
contact spring G thus carthing the negative lead through the stop S; provided
there is no leak, there will be no current through the lamp, and it will not be
incandesced, but if there is a leak the lamp lights up and the bell is rung by
attraction of the armature 0; in the same way on the further rotation of the
drum B the positive lead is tested by the stud F coming into contact with the
spring H. The above description will enable the working of the instrument to be
clearly understood. In the same way we may employ a static voltmeter or
electrometer to be used in connection with the automatic connection for making
contact.
In place of the bell we may combine with the automatic apparatus a sensitive
galvanometer wound differentially or otherwise, so as to give warning whenever
the leakage occurs.
Having now fully and particularly described the nature of our invention what
we claim is:-
(1) An apparatus for testing automatically the insulation of a circuit or circuits
at certain prearranged intervals of time, substantially as described.
(2) An apparatus for automatically giving warning when the insulation is below
a prearranged amount substantially as described.
(3) An apparatus which at given intervals automatically indicates whether an
existing leakage above a predetermined amount be in the positive or negative
main.
KEGINALD JOHN JONES.
WOODHOUSE & RAWSON UNITED, LIMITED,
W. T. Switchbury, Secretary.