Improvements in Switching Apparatus for Transformers for Alternating Current Systems of Electrical Distribution.
Year: 1897

page_text: Date of Application, 7th Dec., 1897-Accepted, 29th Jan., 1898
COMPLETE SPECIFICATION.
Improvements in Switching Apparatus for Transformers for
Alternating Current Systems of Electrical Distribution.
I, EUSTACE OXLEY, of 1242, 11th Street, Northwest, Washington, in the
District of Columbia, United States of America, Electrical Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement
In many alternating systems of electrical distribution, a current of high tension
is led by conductors of small size to the place where the energy is to be utilised
being converted by tension reducing transformers into a current of suitably. low
tension. The currents being alternating, the transformers commonly used are
substantially similar to induction coils, the primary coils of fine wire receiving the
high tension current, and the secondary coils of larger wire producing the low
tension current.
In all systems of this kind, there exists a serious objection which probably has
discouraged a wider and more rapid introduction of the alternating system, which
otherwise has considerable advantages.
This objection is the heavy loss due to the fact that there are long periods in
every day when the transformer capacity is greatly in excess of the requirements,
and during which the transformers consume energy, even though there. is not a
single unit of work upon the secondary circuit. Upon the average, lamps or
other translating devices, are in circuit consuming current about four to five
hours daily whilst the transformers are consuming current during the whole
day. Attempts have been made to avoid this great waste of energy, but there are
obstacles to be overcome which make the solution one of extreme difficulty.
In the first place the means employed must be simple and safe not prohibitively
expensive, and automatic, so that they come into action by the simple act of
cutting out the last lamp, or other translating device, in the secondary circuit
and that they cut out the primary of the transformer; whilst on the other hand,
the act of bringing a single lamp or other device into operation upon the secondary
circuit, first restores the primary circuit.
My invention relates to means of effecting these objects as I shall describe
referring to the accompanying drawings.
Fig. 1 is a section of the housing enclosing the switch and the operating
magnets.
Fig. 2 is a perspective view of one form of secondary switch, one of the arms
being broken away to shew the electrical connections.
Fig. 3 is a similar view of a slightly modified form of secondary switch,
Fig. 4 is a section of part of a housing, with the upper portion of the device for
opening the primary circuit automatically, upon opening the secondary circuit.
Fig. 5 is a section upon the line X-X in Fig. 4.
Fig. is a diagram of an ordinary arrangement of circuits for alternating
currents with apparatus according to my invention included.

page_text: Fig. 7 is a diagram of similar character, shewing a slightly modified arrangement.
Fig. 8 is also a diagram shewing a further modification.
Fig. 9 and Fig. 10 are similar diagrams further illustrating my invention.
Fig. 11 is an elevation of the interior of a housing containing switch-operating
magnets, which are slight variations of the parts shewn in Fig. 1.
Fig. 12 shews in plan a modification of the appliance shewn in Figs. 4 and 5.
1, indicates a switch for opening and closing the primary circuit of a transformer
of alternating current. The switch 1, which may be termed the primary switch,
has two crossing switch-arms 2 and 3 on a pivot 4 insulated upon a plate 5.
The short ends of the arms 2 and 3 have jointed to them toggle links 6 which
are jointed to a slide bar 7 of nonconducting material. The longer ends of the
arms 2 and 3 carry knife or other contacts 8, which can enter insulated clips 9
to which the primary wires 29 and 30 are connected. The switch is preferably
enclosed within a chamber 10 from which a tube 12 of rubber or other non-
conducting substance, enclosing the slide bar 7 passes to a second chamber 13.
In this chamber are arranged two electro-magnets 14 and 15 and between their
cores lies an armature lever 16 pivotted at 17, and near its end jointed to the
slide bar 7 beyond which are two contact fingers 18 and 19, projecting on opposite
sides of the armature lever. At the sides are contact springs 20 and 21 on which
the contact fingers 18 and 19 can press when the armature lever is attracted by
the magnets 14 or 15. From the contact 20 a wire 22 leads to the coil of the
magnet 15, and from 21 a wire 23 leads to the coil of the magnet 14. The
wires 22 and 23 are taken from the coil of 15 and 14 to terminals 24 and 25
respectively.
A wire 26 connects 'the armature lever 16 to a middle terminal 27.
When a current flows through the wire 22 energising the magnet 15, the
armature lever 16 is drawn to the right, as in Fig. 1, thereby tending to straighten
the toggle links 6 and draw the contact ends of the arms 2, 3 towards each other,
thus throwing the contacts 8 into the clips 9 and completing the circuit of the
wires connected to the clips through the arms 2 and 3.
When the circuit of
magnet 15 is opened and that of magnet 14 closed, the armature is drawn to the
left and the knife contacts 8 are thrown out of the clips 9.
Referring to Figs. 6, 7 and 8, where the parts already explained are indicated
by reference signs used in Fig. 1, the two housings 10 and 13 are arranged in an
ordinary alternating system. I will first refer to that shewn in Fig. 6.
29 and 30 indicate the wires of the primary circuit, and 31 the primary coil
of the transformer. 32 and 33 denote the wires of the secondary circuit, and 34
the secondary coil of the transformer. ff are the usual safety fuses and Ma
meter, a few lamps 35 are shewn connected in the secondary circuit.
The wires 29, 30, are led into the housing 10, being carefully insulated and
secured to the clip 9, the opposite attractions of the magnets 14 and 15 opening
and closing the primary circuit as described.
At a suitable place in the secondary circuit is placed a switch, such, for
example, as that shewn in detail in Fig. 2. It consists of two parallel conducting
arms 36 each pivotted at one end to a post 37, to which the wires of the secondary
circuit, are connected. The arms 36 are connected at their other ends and near
their middle by non-conducting transverse bars 38 and 39. When turned in one
direction, the movable ends of the arms 36 enter clips 40, to which the other
ends 41 of the severed secondary wires are connected.
In this position the switch completes the secondary circuit, and when the
arms 36 are withdrawn from the clips 40 the secondary circuit is opened.
On the base-plate of the switch is fixed a contact spring 43, lying near but not
in touch with a conducting post 44. From this post a pin 45 projects over the
contact spring 43 in such position that when the switch is opened, as in Fig. 2,
the contact spring 43 and pin 45 are in contact. Upon the switch base and
underneath the free end of the contact spring 43 is a stop block 46, so placed that

page_text: when the arms 36 are brought into the clips 40, a buffer 47 carried by the trans-
verse bar 39 presses the contact-spring 43 on the stop-block 46.
From the three parts 43, 44 and 46, are led wires 48, 49, and 50, respectively.
The wire 4S is led to one pole of a local battery or generator 51 (Fig. 6) and
from the other pole to the terminal 27 on the housing 13.
The wire 49 is led directly to the terminal 25, and the wire 50 to 24.
Assuming that the switch is in the position shewn in Fig. 6, and that it is
desired to close the circuit; the arms 36 are moved towards the clips 40, but
before reaching them the spring buffer 47 meets the contact-spring 43, draws it
away from the back stop 45, and as the arms 36 move still farther, the contact
spring 43 is moved against the stop-block 46 an instant before the arms 36 com- .
plete the secondary circuit, thereby establishing the local circuit through the
magnet 15, attracting the armature 16, and by the toggle-link levers 6 operating
the switch arms 2 and 3, and completing the primary circuit of the transformer.
The opening of the primary circuit by the switch, is practically an exact reversal
of the steps for closing it. In each operation, the local battery and circuit are
in action for a moment only, the expenditure of energy of the battery being so
small that it will probably serve for a year or two before requiring to be charged
or replaced.
The arrangement of parts shewn in Fig. 7 is the same as that seen in Fig. 6,
the sole alteration being that instead of the local battery 51, I substitute a small
transformer 52, which remains constantly in circuit with the primary. This small
transformer supplies the coils of the magnets 14 and 15, and its size is such that
the loss due to its being constantly in circuit, is so small that it may be disregarded.
The arrangement of circuits is practically the same, except that the wire going
to 27, instead of being connected to one pole of the battery, forms part of the
circuit of the secondary coil of the small transformer.
I will now describe the arrangements for cpening the primary circuit when the
last translating device is cut out. This is illustrated in Figs. 8 to 12 included,
but it includes a feature shewn in detail in Figs. 4, 5 and 12 which I will now
describe.
It is a small electric motor having a shaft 53, carrying an arm 54 tending to
rotate as indicated by an arrow in Fig. 5. Upon the shaft 53 is coiled a spring 55,
connected to the arm 54 and opposing its rotation. This motor may be as shewn
in Figs. 4 and 5, in which, there is one arm 54 projects upon one side of the shaft.
As shewn in Fig. 12 there are two opposite arms.
On a housing 56, is mounted a bracket 57, upon which is pivotted a bell crank
lever 58, one arm of which lies in the path of the arm 54.
The other arm bears against a spring contact 59, which is normally held by
its own elasticity away from a second contact 60, but can be pressed against it by
slightly turning the bell-crank lever 58 thus closing the circuit which includes
the contacts 59 and 60. In Fig. 8, this circuit is that which includes the local
battery 61. The motor is enclosed within any suitable form of housing or box 56,
the end of the shaft and the arm 54 being the only parts which lie outside.
From the contacts 59 and 60, wires 63 and 64 are led, 63 to a wire 65, which
goes to one pole of the battery 61, and 64 to the terminal 25 upon the magnet
box 13.
At the instant when the arm 54 is turned by the spring 55 bringing
the contacts 59 and 60 together, a local circuit, including the battery 61, is
closed through the coil of the magnet 14, the result being to attract the
armature 16, move the slide-bar 7 and through the toggle-links 6, spread the
switch arms 2 and 3 withdrawing them from the clips 9, and thus opening
the primary circuit of the transformer. As the motor revolves in the direction of the
arrow, the arm 54, in passing the bell-crank 58, merely trips it drawing its other
arm away from 59, so that no effect is produced. The rotation of the arm 54
continues until it is arrested by a pin 66 projecting from the top of the motor
casing 62. This movement puts the spring 55 under tension, and as the arm 54
is pressed against the pin 66, as long as there is any current in the secondary

page_text: circuit, the tension of the spring is preserved until the current in the secondary
circuit ceases. A switch suitable for opening and closing the secondary circuit
shewn in Fig. 3, has two conducting arms 36 pivotted upon terminals 37 and
transversely connected by non-conducting pieces 38 and 39.
These parts, as well as the terminals 41, being the same as those shewn in
Fig. 2, are indicated by the same reference numerals. This switch as that shewn
in Fig. 2 is provided with an operating handle 36
From the base plate of the switch rises a post 67 of non-conducting material
forked at the top to receive a tripping finger.68 which is pivotted in the fork and
projects on both sides of the post, the projecting portion upon one side lying in
the path of the transverse arm 39 as it is brought down to close the switch.
On the other side of the post the projecting portion hangs down and carries
the elastic contact 69, connected to a wire 70, which is led by a wire 71, to the
terminal 24 of the magnet housing 13.
Near the contact 69, is a second contact 72, from which a wire 73 is led by the
wire 65 to one pole of the local battery 61. The operation of the switch in closing
the secondary circuit is the same as in Fig. 6, the circuits being shewn in Fig. 8.
The motor housing 62 being connected to one side of the secondary, as seen in
Fig. 8, and the secondary switch being open, as there shewn, let it be assumed
that it is desired to close the secondary circuit, thereby effecting the automatic
close of the primary of the transformer. To effect this, the operator simply
presses the switch arms 36 down, until they enter the clips 40, but before reach-
ing this position the bar 39 engages the tripping finger 68, pressing it downward
and bringing the contacts 69 and 72 together. This closes a circuit over
wires 70, 71, terminal 24, wire 22, through the coil of electromagnets 15, and
thence by way of the terminal 20 and armature 16, through the terminal 27, to
one pole of the battery 61. From the other pole the circuit is completed by
wires 65 and 73, back to the other terminal 72. The magnets 15 being thus
energised, the armature 10 is attracted, the slide-bar 7 is drawn into the housing 13,
and the switch-arms 2 and 3, being moved toward each other, the terminals 8 are
thrown into the clips 9, thus closing the primary circuit of the transformer, just
an instant before, or during the operation of closing the secondary switch. At
the moment when the local circuit is closed, as described, the armature 16, in
Fig. 1, lies in a position in which its contact 18 is against the spring-contact 20.
After the circuits are closed by the secondary switch, the position of the armature
is that shewn in Fig. 1, with its contact 19 against the spring contact 21.
The instant that the secondary circuit is completed, and the primary circuit of
the transformer closed, the small motor receives current and is turned in such a
direction as to cause its arm 54 to trip the bell-crank 58, without closing the
contacts 59 and 60. The rotation of its shaft continues until stopped by the
pin 66, where it is held, with the spring 55 strained in readiness, upon opening
the secondary circuit, to turn the arm 54 in the contrary direction, and to bring
it against the bell-crank 58, and cause the latter to press the contact 59 against
the contact 60. This closes a local circuit over the wire 63 and 65, through the
battery 61, to the terminal 27, and thence by way of the armature 16, contact 19,
spring contact 21, wire 23 coil of the electro-magnets 14, to terminal 25, and
thence by wire 64, back to the contact 60. The magnet 14, being thus energised,
for a moment, attracts the armature 16, pushes the slide-bar 7 out of the magnet
housing 13, and spreads the switch arms 2 and 3, thereby opening the primary
circuit of the transformer.
As the secondary switch closes the contacts 69 and 72 are held together for an
instant, long enough to give operative action to the magnet 15. The moment,
however, that the bar 39 passes the finger 68, the elasticity of the contact 69
causes it to resume its normal position, and separates these contacts, thus opening
the circuit of the magnet 15 the instant this action is complete.
The modification shewn in Fig. 9 differs from that shewn in Fig. 8, merely in

page_text: substituting a very small transformer 74, for the local battery 61, the operation
in other respects being exactly the same.
In Fig. 10, I have shewn a motor arranged in its casing 62, which varies from
that already described by having two arms 54 and 54° Fig. 12. This duplication
of the arms involves a duplication of the contacts 59 and 60 and the bell-crank 58,
so that the arms operate both bell-cranks simultaneously.
This constitutes practically a double-pole switch, involving a slight change in
the circuits as I shall now describe.
The motor shewn in Fig. 12 is interposed upon one side of the secondary circuit,
as shewn in Fig. 10 in which the contacts 59 and 60, on the right of Fig. 12, and
the bell-crank 58 are so numbered.
On the other side of the motor, the bell-crank is marked 58, and the contacts
are marked 59 and 60°.
From the contact 59, a wire 76 goes to one side of the secondary circuit, and
from the other contact 60 a wire 77 is taken to a terminal 78 upon the end of the
magnet-housing 79, shewn in Fig. 11. From the contact 59, a wire goes to the
other side of the secondary circuit, and from 60, a wire 80 goes to a terminal 82,
near 78. From a third terminal 83, a wire 84 goes by the local battery 85, to
the contact spring 72 upon the secondary switch, shewn in the branch circuit in
Fig. 10, a shunt wire 84 being also taken to the same contact in the main
secondary switch.
From the fourth terminal 86, a wire 87 is taken to the other contact 69 of the
secondary switch. From these four terminals, the circuits within the magnet
housing 79, are shewn in Fig. 11, that is to say, from 78 a wire 88 is carried to a
spring terminal 89, and from an adjacent terminal 90, which is normally out of
contact with 89, a wire 91 is led to the electro-magnet coil 92 from which a wire 93
goes to terminal 82.
From 83, a wire 94 goes to the electro-magnet coil 95, whence a wire 96 is led
to a spring terminal 97, normally out of contact with a second spring terminal 98,
from which a wire 99 is carried back to the terminal S6. The armature 16"
forms no part of any circuit, but upon its vibrating end, it carries a cross pin 100,
of non-conducting material, projecting upon both sides and bearing alternately
against the spring contacts 89 and 98, in order to preserve the circuit of either
magnet until the moment when the circuit of the other is to be closed. Otherwise
the parts do not vary from those shewn in Fig. 1, but like those in Fig. 1 operate
the primary switch as already described.
The main secondary switch which cuts the transformer into or out of circuit
when current is turned on, or off, in the secondary circuit, is intended for use in
places where all the lamps, or other translating devices are connected on this
one switch, and where this is the only switch operated by the consumer in turning
the secondary current on or off, as for example in shops where lamps are installed
in windows or elsewhere, and are all controlled by this single switch,, or where
motors are under the control of one switch only.
On the other hand, when the electric motor, or as it may more properly be
termed, the single pole or double pole switch, is used, the turning off of all the
lamps, or other translating devices except one only, has no effect upon the primary
switch. When the last lamp is turned off, however, leaving the secondary circuit
without current, the single or double-pole automatic switch instantly operates
under the force of its spring, and closes the local circuit which supplies current
to the electro-magnets that operate the primary switch. In neither case, there-
fore, is it necessary to depend upon the attention or services of the consumer,
as the mere act of turning off the translating devices in the secondary circuit
is inevitably followed by the automatic opening of the primary switch and the
cutting out of the transformer, so that no opportunity is allowed for waste of
energy.
The entire apparatus is simple, involves very few parts, is not expensive in
construction or installation, requires no skill or experience to operate it, and

page_text: wholly removes one of the most serious and important difficulties attendant upon
alternating systems of distribution.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is :-
1. In an alternating system of electric distribution, having a transformer, the
combination of a switch to open and close the primary circuit of the transformer,
a switch to open and close the secondary circuit, electro-magnetic apparatus to
control the primary switch, a source of electric energy to supply current to said
apparatus, circuit closing devices arranged in the secondary circuit and capable
of movement under the energy of the current in said circuit against a counter-
acting force, and contacts to complete the circuit of said electro-magnetic devices
by the back movement of the circuit-closing device when the last translating
device and all current is cut out of the secondary circuit, substantially as set forth.
2. In an alternating system of electric distribution, the automatic means for
opening the primary circuit of the transformer upon the removal of the last
translating device from the secondary circuit, substantially as set forth.
3. The double-pole switch for opening the primary circuit of the transformer
when the last translating device is cut out of the secondary circuit substantially
as set forth.
4. The primary switch, consisting of two pivotted arms, connected by toggle-
links to a slide-bar, an armature connected to the bar, and electro-magnets
arranged to attract the armature in opposite directions as their circuits are auto-
matically closed by a switch in the secondary circuit, substantially as set forth.
Dated this 7th day of December 1897.
ABEL & IMRAY,
Agents for the Applicant.