Improvements in the Distribution of Electricity and in the Apparatus Employed therein.
Year: 1890

page_text: Date of Application, 29th July, 1890
Complete Specification Left, 29th Apr., 1891-Accepted, 30th May, 1891
PROVISIONAL SPECIFICATION.
Improvements in the Distribution of Electricity and in the Apparatus
Employed therein.
I, THOMAS TOMLINSON, of Lynton, Durham Road, Raynes Park, in the County
of Surrey, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention particularly relates to systems in which transformers are used,
though it may be employed wherever it may be necessary to insert and take out
electrical units under similar conditions.
Sufficient transformers have to be provided to deal with the maximum load; now
there are long periods in each day when the transformer capacity is greatly in
excess of the requirements of the district or consumer and during this time whether
lamps are connected to the secondary or not there is waste of current in the
primaries.
I provide apparatus to be attached to groups of transformers at sub-stations or
elsewhere for the purpose of disconnecting some of the transformers in each sub-
station when the load on the secondary diminishes and for replacing them as it
increases.
It is essential in such an apparatus that no possible failure should occur in
replacing transformers, as such a failure would cause the burning out of the trans-
formers already connected or the cutting off of the lights by blowing of the safety
fuses.
My apparatus is therefore so arranged that the mechanism for inserting the
switches is so far as inserting the switches is concerned entirely independent of that
for taking them out and yet when it comes to taking out switches absolutely
controls the latter.
In fact the easing of one brake determines the putting in of switches, whilst for
the taking out of switches this brake must be hard on in addition to another brake
being cased. This is attained by making the brake in the first case a pair of
friction wheels which act as gear wheels in the second case but only when liard on
as a brake.
Special devices are also provided for protecting the system against the con-
sequences of imperfect contact at the switches and to prevent hunting.
In each sub-station or other corresponding place I divide my transformers into
groups each group containing a reasonable percentage, say twenty per cent. of the
total number of transformers in the sub-station.
t
I provide one transformer with the magnetic circuit open and with an armature
or other appliance to enable it to exert a pull on a lever. The rest of the trans-
formers are of the ordinary type.
This open magnetic circuit transformer is never disconnected. It is provided
with an armature to which a suitable weight is attached so that the armature is not.
lifted until the average load on the transformers exceeds a certain amount say four-
fifths of full load.
The lifting of this armature eases a suitable brake and allows a weight to
descend.
The lifting of the armature may of course be done by an ordinary electro-
magnet whose circuit is closed by a relay operated by a solenoid round which the
primary current of any one of the transformers which always on circulates.
Assume that the load is small and that only one group of transformers is on
including the open magnetic circuit transformer then as the load increases the pull
of the open magnetic circuit transformer on its armature increases until the

page_text: armature is lifted so releasing the brake and allowing the weight to fall causing a
train of mechanism to come into action.
This mechanism consists of five or other number of switch-arms each switch-arm
carrying two switches one for the primary and one for the secondary of its corre-
sponding group of transformers.
The arrangement of the switches may be such that the secondary circuit is
broken just before the primary, or preferably they may be broken simultaneously
to prevent sparking.
Each switch-arm is moved so as to open or close the switches by a loose arm
controlled by a tumbling weight so as to ensure quick make and brake.
This arm is moved by a sliding wedge drawn along by the weight already
referred to which is released on the rise of the armature of the open magnetic
circuit transformer or electro-magnet.
This wedge travels from end to end of the bench upon which the switches are
set and connects the different switches successively.
The taking out of transformers is provided for as follows:-
As soon as the average load on the transformers at the time in circuit sinks to
say half full load the core is released from a solenoid round which the primary or
secondary current of the regulating transformer flows and closes by a relay the
magnetic circuit of a small electro-motor working through a train of wheels
causing the wedge piece to travel slowly back along the bench, throwing out the
switches one by one by a wedge set back to back to the wedge which acts in the
forward direction and also winding up the weight which controls the replacing of
the switches.
The motor circuit may also be closed by a relay actuated by the open magnetic
transformer direct.
As soon as a sufficient number of switches have been thrown out to bring the
average load on each transformer over half load the motor stops by the breaking of
its circuit at its relay.
At the end of the travel of the wedge piece and when it. has taken out all the
switches in connection with which it operates it comes against a spring stop and in
so doing it opens its own circuit.
In case the motor circuit by any chance remain closed the motor would not as
already explained prevail so as to neutralize the effect of the falling weight which
puts in switches but a hunting to and fro of the wedge piece and a consequent
putting in and taking out of transformers would simply result.
To limit this hunting arrangements may be made to limit the number of revolu
tions of the motor train of gear in one day say by a cogwheel with an interruption
in the cogs or better still as follows: Let the motor circuit be broken at one point
and let the two ends dip into a thin metal cup from which they are insulated, let
the bottom of this cup be filled with paraffin wax or other easily fusible non-
conducting material and let the top part be filled with mercury into which the ends
of the circuit dip and through which the circuit is completed."
Let the arrangement be placed in such a position as to be within the influence of
any heating in the motor circuit preferably in connection with a small choking coil.
As the time during which the motor will act under normal conditions is very
short and at long intervals no appreciable heating will take place but if the motor
circuit remains closed by any accident and the current remains on the choking coil
will heat, the wax will melt and the circuit will be broken by the fall of the
mercury to the bottom of the cup.
It is obvious that the energy of a falling weight or of a coiled spring may be
used to replace the motor.
As a precaution against bad contact of the switches the open portion of each
switch is bridged across by an instrument so designed that on exposure to moderate
heat it establishes an electrical connection independent of the switch contacts.
For this purpose two metal connecting pieces of the following construction are
used. One end of each dips into a metal cup which is insulated from it and which

page_text: is lined with paraffin wax or other easily fusible insulator, inside the paraffin wax
and surrounding the end of the connecting piece is mercury. The other end of
each connecting piece is directly connected to another metal cup into which one end
of the other connecting piece dips as above described.
These cups are inserted into suitable sockets forming part of the metal base of
the switch contacts.
In case of bad contact being made anywhere the switch will heat slightly this
will melt the paraffin which will float to the top of the mercury and a contact will
be made between the end which dips into the cup and the cup itself through the
mercury thus throwing that part of the apparatus temporarily out of gear so far as
the electrical taking out of the switch is concerned and preventing any accident,
the mechanical movement of the switch is not interfered with.
This apparatus will also allow of the use of spare transformers which would be
switched in when through the failure of one or more transformers or fuses at a time
when the station transformers were fully loaded a greater load than they could
safely carry might otherwise be put on to those remaining.
Dated this 29th day of July 1890.
CARPMAEL & Co.,
Agents.
COMPLETE SPECIFIGA ITUN.
Improvements in the Distribution of Electricity and in the Apparatus
Employed therein.
I, THOMAS TOMLINSON, of Lynton, Durham Road, Raynes Park, in the County
of Surrey, Engineer, 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 :—
·
My invention particularly relates to systems in which transformers are used,
though it may be employed wherever it may be necessary to insert and take out
electrical units under similar conditious.
Sufficient transformers have to be provided to deal with the maximum load;
now there are long periods in each day when the transformer capacity is greatly in
excess of the requirements of the district or consumer and during this time whether
lamps are connected to the secondary or not there is waste of current in the
primaries.
I provide apparatus to be attached to groups of transformers at sub-stations or
elsewhere for the purpose of disconnecting some of the transformers in each
sub-station when the load on the secondary diminishes and for replacing them as
it increases.
This apparatus is so arranged as not to require the presence of an attendant at
the sub-station or place where the transformers are situate.
It is essential in such an apparatus that no possible failure should occur in
replacing transformers, as such a failure would cause the burning out of the
transformers already connected or the cutting off of the lights by blowing of the
safety fuses.
My apparatus is therefore so arranged that the mechanism for inserting the
transformers is so far as inserting the transformers is concerned entirely independent
of that for taking them out and yet when it comes to taking out transformers
absolutely controls the latter.
I so arrange that the transformers are put into circuit by the descent of a weight
which is liberated by the action of an electro magnet.
The transformers are taken out of circuit by the action of an electrically
controlled motor mechanism which also when in action lifts the weight above

page_text: mentioned. Thus notwithstanding any failure which may occur in the motive
power the weight will always be in readiness to put in such transformers as are out
as soon as the requirement arises.
In place of a weight I may employ an equivalent such as a metal spring but the
use of a weight, being simpler, is preferable.
The motor mechanism may be of any convenient sort but a train of wheels put
in motion by the descent of a sufficiently heavy weight is usually the most
convenient.
As a precaution against heating of the contact parts I bridge them over with an
instrument so contrived that as soon as a rise in temperature occurs the current is
able to pass freely by the bridge, which however allows no current to pass so long
as the parts remain cool.
In order that my invention mar be fully understood. I will proceed to describe
Figure 1 is an elevation of the apparatus which I employ to put transformers
into and out of circuit; it can also be employed when required to connect and
disconnect other electrical units, as battery cells, when it is required so to do.
Figure 2 is a plan of the apparatus.
Figure 3 is an end elevation and
Figure 4 is a transverse section of the upper part.
Figure is similar to Figure 4 but is drawn to a larger scale.
Figure 6 is a plan partly in section of some of the parts seen in Figure 5.
Figure 7 is a vertical section of the bridge appliance which when heating occurs
establishes good electrical connection between the parts to which it is applied.
Figure 8 is a plan of the bridge appliance.
Figure 9 is a diagram shewing some of the electrical connections.
a a is the frame of the machine and a is a table surface forming part thereof.
Over the face of the table and passing along it horizontally from end to end there
is a bar it is supported at the ends by brackets a² a².
The circuit wires of the transformers which it is required to put into and out of
use from time to time are also brought to this table and are there connected with
carefully insulated plates c c. The apparatus shewn by the drawings is adapted
to control the connections of four sets of transformers; in addition to which there
is a transformer or a set of transformers which always remains at work. This
latter transformer or set of transformers has its primary coils always connected
with the primary mains and its secondary coils always connected with the secondary
mains or circuit wires. The other transformers or sets of transformers when
brought into use are coupled in parallel with the first but when a transformer is
out of use there is a gap or opening in its primary and another gap or opening in
its secondary. In each case the gap or opening is the interval between a pair of
plates c c.
There are four pairs of plates c on either side of the table or sixteen plates in
all; the plates on one side receive the primary wires and those on the other side
the secondary wires and these are made fast to the plates in such a way as to
ensure good permanent connections.
dddd are four circuit closing arms mounted upon the bar in such manner
as to be able to turn upon it. The arm in each case is so made that its extremities
are effectually insulated the one from the other and each extremity is double or
forked and so made as to form a good electrical connection between two plates c c
which constitute a pair. As shewn in the drawings cach arm terminates on one
side in two downwardly directed wedge like ends did which are in one piece or in
good electrical connection the one with the other but for additional security are
insulated from the rest of the arm. These wedge pieces d' d' when depressed each

page_text: e.
On
enter between a pair of metal combs c* c* forming part of one of the plates
On the other side the arrangement is similar and the wedge like projections d*
enter between combs upon the two plates c c. In either case when the wedges are
between the combs there is good metallic connection between the two plates c c of
the pair and the transformer or set of transformers in connection with the two
opposite pairs of plates is in operation. When on the other hand the armd is turned
about the bar so as to withdraw the wedges from between the combs, the
transformer or set of transformers, is put out of use, there being then a gap or
opening both in its primary and in its secondary circuit. The wedges d' serve to
make the primary connections and the wedges the secondary or low tension
connections. The contacts are preferably so arranged that the primary and
secondary circuits are opened as nearly simultaneously as possible. ee are heavy
armed levers which are mounted on and able to turn about the bar to a certain
extent independently of the arms d d. Each lever e is formed with two checks
or discs and these are connected by four bolts el e' which are clothed with vulcanised
india rubber to strike softly on the parts with which they come into contact.
each lever also two small radially set rollers are mounted. is a double wedge
piece mounted upon a carriage ƒ which by means hereinafter described can be
made to travel along the table in either direction. The double wedge as it passes
each lever comes into contact with one or other of the rollers upon it; it
raises the lever to a vertical position and causes it to pass somewhat beyond and
then the lever by its own weight falls suddenly over. As the lever falls the
bolts ele strike the arm d and so the position of the arm is suddenly reversed, it
is raised on one side and depressed on the other until it is brought to rest upon
one or other of the stops a* on the frame. When the wedge piece f travels from
right to left (as seen in Figures 1 and 2) it brings the levers which it passes to
the position.shewn in Figure 4 that is to say it puts transformers into circuit,
when on the other hand it travels from left to right it takes out transformers. The
carriage is attached to an endless chain g which passes around a chain wheel at
one end of the table and a pulley at the other end; there are also intermediate
guide pulleys. The wheel is free to turn upon an axis & which is mounted in
bearings on the frame. is a cord attached to the chain on the under side and
passing over a guide pulley to the weight m: When the wheel is free the pull
of the weight upon the chain moves the carriage from right to left and transformers
are put on. Except when this is required the wheel is locked in the following
manner to its axis k. n is a toothed wheel fast with the wheel and also free to
turn upon is another toothed wheel fast upon the axis & ppare two pinions
fast on a spindle carried in bearings at one end of a lever y having its fulcrum
on the frame at 7. At the other end of the lever there is a weight 2, this holds the
pinions in gear with the wheels / and o. The wheel when so locked can only
turn when the axis k also revolves; but this axis is usually held fast by a brake
wheel upon it and a strap made to bear upon the periphery of the wheel by a.
weight. s is an electro-magnet which when a current passes in its coils attracts
the armature s' attached to the lever, the pinions p p are then drawn down until
the wheel is out of gear and the weight m then operates to put in transformers
until it is stopped by the pinions p again rising.
The teeth of the wheel o are sufficiently long not to disengage.
t is a drum fast on the axis k, it has a rope t¹ wound around it; the rope passes
over an overhead pulley and a heavy weight competent not only to work the
switches but also to lift the weight m is attached to it. When the brake wheel'>
is relieved from the pressure of the brake strap upon it the rope is drawn off
from the drum t and the axis k revolves. If the pinions p are in gear (but not
otherwise) the wheel also will turn and the carriage will be drawn from left to
right and transformers will be taken out of circuit.
At the same time the weight m will be raised. The release of the brake wheel-r
is effected by the electro-magnet u, when a current passes in the coils of this magnet

page_text: it attracts its armature and this being attached to the lever the lever is lifted
and so also are the weights which are immediately over the end of the lever.
The magnets and may be supplied with current to energise them in various
ways; one way is illustrated schematically by Figure 9. e is an electro-magnet.in
the secondary circuit of that transformer which remains always at work; it has
two armatures carried on levers which at their further ends are provided
with points dipping down into mercury cups and then electrically connecting the
contents of these cups.
is
When the current through the transformer which remains permanently in circuit
and in the coils of the magnet w is neither too large or too small the magnet
able to hold up the lever w' but is unable to raise the counterweight w* attached to
the lever o consequently both pairs of points stand out of the mercury cups.
Circuit wires pass from the cups as shown to the magnets s and u (which are the
same as the magnets similarly lettered in the preceding figures) and these wires
are continued to the central station. At the central station the wires are connected
with any convenient lamp circuit, the connections being through resistance or
choking coils to moderate the current which passes when first the points dip
into either pair of cups. yy are two bells of different tone included in the circuits.
When the points of either of the levers we or dip into the mercury the
corresponding bell rings, showing that the current in the magnet w and in the
transformer circuit in which the magnet is included is too large or too small as
the case may be. An indicator may also be provided at y¹ to give the same
information visibly.
and are switch levers. The attendant on hearing the call closes the corre-
sponding switch short circuiting the coil and a more powerful current then passes
which energises the magnets s or as the case may be. It is advisable that the
switch levers and should be connected so that the switch 22 may always be
closed when is closed, although may be closed independently of 2. This
arrangement forms an additional precaution against too many transformers being
put out of work.
If it be thought expedient to dispense with the control of the
attendant at the central station it may be so arranged that the dipping of the points
on the levers w² shall at once transmit a current to energise the magnets u and s,
in this case it will be unnecessary to lead circuit wires from the magnets to
the central station. In place of mercury cups other forms of contacts may be
employed.
Figure 9 illustrates also the arrangement of the transformers in groups increasing
in geometric progression.
The apparatus above described affords very complete precaution against
transformers being taken out or left out of circuit when they should be in use.
A
The motor mechanism cannot take transformers out of circuit unless the
magnets and s conspire to permit it and then it cannot do so without storing up
power in the weight min readiness to put transformers again into circuit.
current passing in the coils of the magnet s will always cause transformers which
may be out of circuit to be put in whatever be the state of the magnet u and
whether the motor mechanism is in efficient operation or otherwise.
It may occasionally happen that the rocking arms d d already referred to form
imperfect contacts with the plates c; dust or dirt between the contact surfaces may
cause this and heating and injury to the apparatus might result. It is necessary to
guard against this danger. I do this by providing on each of the plates ca socket e
and I connect the sockets of each pair of plates by an instrument of which the
construction is shown by the Figures 7 and 8. This instrument is made for the
most part of vulcanized fibre and it has a wooden handle. On its under side are
two hollow metal plugs A' A2 adapted to fit into the pair of sockets de: Each
plug has a lining A of paraffin wax within it, formed by melting paraffin in the
plug, cooling the plug externally until its walls are coated to a sufficient thickness,
and then pouring out the still fluid residue. The plug so prepared is partly filled

page_text: with mercury and it is secured in its place upon the vulcanized fibre support by
bolts B B' which also serve to electrically connect it with one or other of the metal
plates CC the plug A¹ being connected with the plate C and the plug A³ with
the plate C. The plate C¹ is also electrically connected with the pin D and the
plate C with the pin D. The pin D₁ dips into the mercury within the plug A³
and the pin D into that in the plug A'. The plugs A A² are therefore effectually
insulated from each other when cold. When however either of the plates e becomes
heated in consequence of an imperfect contact made by the arm & the heat is
communicated to one or both of the plugs A¹ A² the paraffin melts; the inercury is
then in contact with both the plug and the pin, and the current then passes freely
from plug to plug. An effectual connection is thus made but the contact so made
remains until the machine is inspected. This appliance will also be found useful
in other cases where heatings from imperfect contacts are liable to occur.
C
In the apparatus shown by these drawings the motor mechanism which takes the
transformers out of circuit is wheelwork actuated by a heavy weight attached to the
rope but it might be an electro motor operating to turn the axis & and supplied
with current for this purpose when the electro magnet u receives its current. Or
other motors may be employed. But whatever the motor it always when taking out
transformers also lifts the weight m or its equivalent as above described so that
although the motor may run down or cease to work from any cause there is always
power available to put all the transformers into circuit when called for and no injury
to or burning up of the transformers can then result.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. Apparatus substantially as described in which when it is necessary to connect
transformers (or other electrical units) into circuit it is effected by the release of a
weight or its equivalent; and when it is desirable to take transformers out of
circuit it is effected by motor mechanism, which at the same time that it causes the
transformer circuits to be opened winds up a weight or its equivalent in readiness
to again close the circuits as soon as it may become necessary to do so.
2. In apparatus for connecting and disconnecting transformers (or other electrical
units) effecting the disconnection by motor mechanism operating through gear
wheels which are separated by the operation of the magnet s when transformers
should be inserted.
3. In apparatus for connecting and disconnecting transformers (or other electrical
units) the combination of parts consisting of the contact arms d and contact parts
in connection therewith; the weighted rocking levers e operating upon the arms to
close and open the contacts and the wedge piece and its carriage f¹ which in
traversing causes the levers e to fall over from side to side substantially as
described.
4. In apparatus for connecting and disconnecting transformers (or other electrical
units) the combination of parts consisting of the axis k; motor mechanism for
rotating the axis ; electrical mechanism for starting and stopping the rotation of
the axis ; the chain wheel electrical mechanism putting the chain wheel into and
out of gear with the axis k; the endless chaing; and the wedge of moved by the
chain and operating the switches substantially as described.
5. In apparatus for connecting and disconnecting transformers (or other electrical
units) bridging over the contact parts with an instrument containing a fusible
insulator which if heating occurs operates substantially as described and allows a
good and permanent metallic contact to be established.
6. An apparatus for establishing electrical connection between parts on the same
becoming heated; such apparatus being furnished with a hollow plug or plugs lined
with paraffin or like material and containing mercury and also a pin dipping down
into the mercury as above described.

page_text: 7. In apparatus for connecting or disconnecting transformers the arrangement of
the contact levers substantially as described so that the primary and secondary
circuits are broken simultaneously so as to prevent sparking.
8. Apparatus substantially as described and represented by the annexed drawings,
Dated this 29th day of April 1891.
CARPMAEL & Co.,
Agents for the Applicant.