Improved Means for Effecting the Insulation of Electrical Trans- formers, Switches, Switch Boards, Fuses, Commutators, and Commutator Brushes.
Year: 1889

page_text: Date of Application, 6th Sept., 1889
Complete Specification Left, 2nd May, 1890-Accepted, 5th July, 1890
PROVISIONAL DE MOITICATIO
Improved Means for Effecting the Insulation of Electrical Trans-
formers, Switches, Switch Boards, Fuses, Commutators, and
Commutator Brushes.
We, WALTER CLAUDE JOHNSON of The Dignaries Westcombe Park, Blackheath S.E.
and SAMUEL EDMUND PHILLIPS Castle House, Shooters Hill Kent Electrical Engineers
do hereby declare the nature of this invention to be as follows:-
:-
Our invention has mainly for its object to obtain a better insulation of electrical
transformers, switches, switch boards fuses, commutators and their brushes, and it
consists in immersing these apparatus in, or surrounding them by, a non conducting
liquid such as mineral oil, or other suitable liquid whereby they are protected from
the atmosphere, and at the same time sparks that may be produced are immediately
extinguished, and any tendency to form an arc is greatly lessened.
For this purpose, in the case of electrical transformers we place them in a tank or
casing containing the insulating fluid, or the construction of the usual cast iron outer
case may be so arranged that it will itself form the receptacle for the insulating fluid.
The transformer with its coils is for this purpose by preference first desiccated in
an oven or otherwise thoroughly dried, and is then immersed in the insulating fluid in
the case, or the fluid is poured in afterwards. Or the whole apparatus and liquid may
be heated so as to expel moisture from the coils or other parts of the apparatus.
By this means a very high insulation may be obtained, and the transformer is
protected from all moisture or from the decay which takes place in most substances
when exposed to the atmosphere; also the noise which attends the action of a trans-
former is greatly lessened.
In applying the invention to switches or switch boards and fuses, especially those
used in connection with high potential alternating or continuous currents these
apparatus are in like manner placed in receptacles which are filled with insulating
fluid.
By this means, in the case of switches, it is much more easy to break a circuit, as
the arc that might otherwise be formed between two or more points is quickly
extinguished; also in the case of fuses, the liability to form an are on the rupture of
a fuse is greatly lessened.
As insulating fluid may be used, any suitable permanently liquid substance, or a
solid substance which by the normal heating of a transformer or by the heating or
rupture of a fuse, will assume the liquid condition; also any fluid having a resistance
to the passage of a current greatly in excess of that of the parts of the apparatus
through which a current might accidentally pass.
For example, water may in certain cases be used as an insulating fluid, when its
resistance is high compared with the circuit to which it is related, as in the case of
fuses, where water may be used with advantage to extinguish an are which might
otherwise be formed on the rupture of the fuse.
Also when water is employed, it may be covered by a layer of oil to prevent its
evaporation.
For the insulation of switches, switch boards and transformers, the employment of
an oil is preferred.
In applying the invention to the commutators of dynamo machines, the commutator
is enclosed in a receptacle containing the insulating fluid, the receptacle being provided

page_text: with stuffing boxes for the shaft of the commutator to pass through when that shaft is
horizontal.
By this means great insulation is obtained, the rubbing surfaces are well lubricated
and all tendency to sparking is lessened or suppressed.
Dated this 6th day of Sentember 1880
ABEL & IMRAY,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improved Means for Effecting the Insulation of Electrical Trans-
formers, Switches, Switch Boards, Fuses, Commutators, and
Commutator Brushes.
"
We, WALTER CLAUDE JOHNSON of "The Dignaries Westcombe Park, Black-
heath S.E. and SAMUEL EDMUND PHILLIPS, Castle House, Shooters Hill, Kent
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 has mainly for its object to obtain a better insulation of electrical
transformers, switches, switchboards, fuses, commutators and their brushes, and it
consists in immersing these apparatus in or surrounding them by a non-conducting
liquid, such as oil or other suitable liquid whereby they are protected from the
atmosphere, and at the same time sparks that may be produced are immediately
extinguished, and any tendency to form an arc is greatly lessened.
For this purpose, in the case of electrical transformers we place them in a tank, or
casing containing the insulating fluid, or the construction of the usual cast iron outer
case may be so arranged that it will itself form the receptacle for the insulating
fluid.
The transformer with its coils is for this purpose by preference first desiccated in an
oven or otherwise thoroughly dried, and is then immersed in the insulating fluid in
the case, or the fluid is poured in afterwards. Or the whole apparatus and liquid may
he heated so as to expel moisture from the coils or other parts of the apparatus. By
this means a very high insulation may be obtained, and the transformer is protected
from all moisture or from the decay which takes place in most substances when
exposed to the atmosphere, also the noise which attends the action of a transformer is
greatly lessened.
In applying the invention to switches or switch boards and fuses, especially those
used in connection with high potential alternating or continuous currents, these
apparatus are in like manner placed in receptacles which are filled with insulating
fluid.
By this means in the case of switches it is much more easy to break a circuit as the
aic that might otherwise be formed between two or more points is quickly extinguished;
also in the cases of fuses, the liability to form an arc on the rupture of a fuse is greatly
lessened.
As insulating fluid may be used, any suitable permanently liquid substance or a
solid substance which by the normal heating of a transformer or by the heating or
rupture of a fuse will assume the liquid condition, also any fluid having a resistance
to the passage of a current greatly in excess of that of the parts of the apparatus
through which a current might accidently pass.
For example, water may in certain cases 'be used as an insulating fluid, when its
resistance is high compared with the circuit to which it is related, as in the case of
fuses, where water may be used with advantage to extinguish an arc which might
otherwise be formed on the rupture of the fuse. Also when water is employed it may
be covered by a layer of oil to prevent its evaporation.

page_text: For the insulation of switches, switch boards and transformers the employment of
an oil is preferred.
In applying the invention to the commutators of dynamo machines, the commutator
is enclosed in a receptacle containing the insulating fluid, the receptacle being provided
with stuffing boxes for the shaft of the commutator to pass through when that shaft is
horizontal,
By this means great insulation is obtained, the rubbing surfaces.are well lubricated,
and all tendency to sparking is lessened or suppressed.
The accompanying drawing shews by way of example some of the various modes in
which our above described invention can be applied.
Fig. 1 shews the application to an electrical transformer. The transformer T is for
this purpose enclosed in a box B filled with insulating liquid and closed by a cover B¹
secured in a liquid-tight manner by screw bolts, the leads from the coils being passed
through stuffing boxes S S. The transformer is supported in an insulated manner
on ribs or studs A projecting from its bottom and is secured in position by bars
and wedges W bearing against lugs L on the sides of the box.
Fig. 2 shews the application of the invention to an electrical switch.
S is the switch, enclosed in a box B filled with insulating liquid, the spindle of
the switch passes through a stuffing box in the cover, and is provided outside with
a handle Ĥ. The leads L L L from the contacts also pass through stuffing
boxes.
Fig. 3 shews the application of the invention to a safety fuse F, which is con-
tained in a box B, filled with water or other insulating liquid, and either left open
as shewn or closed with a cover.
The supports S of the fuse are bolted to the box, and the leads L pass through
stuffing boxes at the ends thereof.
Fig. 4 shews a mode of applying the invention to the commutator of a dynamo
machine, the armature shaft A passes through stuffing boxes in the box B, filled
with insulating liquid and carries within the box the commutator C, immersed in
the liquid.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we claim.
Insulating electrical transformers, switches, switch boards, fuses, commutators and
their brushes by immersing them in or surrounding them by an insulating liquid, in
a box or receptacle containing the said apparatus, substantially as herein described.
Dated this 1st day of May 1890.
ABEL & IMRAY,
Agents for the Applicants.