Improvements in Systems of Electrical Distribution and Circuit- breakers for Use therein.
Year: 1899

page_text: Date of Application (in United Kingdom), 22nd Dec., 1899
Complete Specification Left, 19th Sept., 1900-Accepted, 22nd Dec., 1900
Improvements in Systems of Electrical Distribution and Circuit-
breakers for Use therein.
.
I, LEWIS BUCKLEY STILLWELL, of Niagara Falls, New York, U.S.A., Electrical
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to systems of electrical distribution and to circuit-breakers
for use therein for protecting such systems from injuries resulting from short
circuits and overloads.
•
The object of my invention is to provide an effective means for localising
the interruption of service which, in electric power plants, is likely to be caused
by a short-circuit or overload upon one of the branch circuits of the system.
In large systems of electrical generation and distribution, it is usual to transmit
the electrical energy from the generating station to a plurality of sub-stations,
and from each sub-station energy is distributed for lighting and power purposes
in various directions by local feeder circuits.
If circuit-breakers or fuses of ordinary types be used, a short circuit upon
one of the feeder circuits radiating from a sub-station will frequently result in
a total interruption of service from that sub-station, and will sometimes result in
a total interruption of the service from all sub-stations which are supplied through
the main, transmission circuit, since it is liable to open not only the circuit-
breakers or fuses in the feeder circuit first affected, but also to open the circuit-
breakers or fuses through which the entire amount of power delivered to the sub-
station is conveyed, and in some cases even the circuit-breakers or fuses at the
main station.
According to my invention I so construct the circuit-breaker that a definite
period of time will elapse after the short-circuit is established before the circuit
breaker acts. This period of time being moreover entirely independent of the
quantity of current which flows in the circuit.
In applying these circuit-breakers to a system of electrical distribution com-
prising a generating station with a plurality of sub-stations and local feeder
circuits arranged from the sub-stations, I provide circuit-breakers in the various
circuits so arranged that if a short-circuit occurs on any particular line the
circuit breaker controlling that line shall operate before any of the circuit-
breakers between that line and the generating station can operate. By this
means any branch or feeder which may become short-circuited will be opened with

page_text: certainty without any risk of cutting off the supply of power from other branches
or feeders of the system.
In the accompanying drawings:
Figure 1 is a diagrammatic view of a circuit-breaker, constructed in accordance
with my invention, in its closed position.
Figure 2 is a similar view to Figure 1 shewing the circuit-breaker open.
Figure 3 is a diagram of a system of distribution provided with circuit-
breakers arranged according to my invention.
Referring now particularly to Figures 1 and 2 of the drawings, 1 is an
electric conductor forming one side of a circuit to be protected and including
the primary winding 2 of a transformer 3, one terminal of the secondary wind-
ing 4 of this transformer being connected to one terminal of a coil 5 of a magnet 6.
The armature 7 for the magnet is pivotally mounted upon a suitable bracket or
other support 8, and has an arm 7ª extending beyond the point of support Bo as
to engage with a pin 9 projecting laterally from a substantially vertical rod 10.
The rod 10 is pivotally connected at its upper end to a holding pawl 11, the free
end of which, when in the position shewn in Figure 1, engages with one of the
teeth of an escapement wheel 12 of a clock train 13. The pawl is normally held
in this position by means of gravity and the action of a coiled spring 10% inter-
posed between a portion of the bracket and an adjusting nut 10b on the lower
end of the rod 10. The clock train 13, when free to move, may be operated by
a spring or weight and regulated in any well known manner so as to rotate, at a
certain definite speed, a wheel or disc 14, the body of which is preferably formed
of insulating material and is provided with a conducting strip 15 which extends
over a portion of its periphery. A. contact finger or brush 16 engages with the
periphery of the wheel 14 and constitutes the terminal for one end of the trans-
former secondary 4, and also for one end of the coil 17 of a magnet 18.
The
other end of the coil 17 and one end of the coil 5 are suitably connected together
and to the rim 15 of the wheel 14, by any suitable means.
The circuit-breaker proper may be of any suitable form adapted for auto-
matically opening an electric circuit. In the present case I have shewn it as
comprising a pair of stationary terminals 19, a bridging movable terminal 20.
toggle levers 21, and a handle 22 moving the member 20 into engagement with
the terminals 19, and a latch 23 constituting an extension of the armature 24 of
the magnet 18.
It will be understood from the construction here illustrated and described, that
as long as the parts are in the position shewn in Figure 1 and the current in
the circuit does not rise above the amount for which the clock-train-releasing
mechanism is adjusted, there will be no movement of the clock-train or of the
circuit breaker. If, however, the current increases to such an amount as to
cause the magnet 6 to exert a pull upon the armature 7 sufficient to overcome the
action of gravity and that of the coiled spring 10, the pawl 11 will be raised out
of engagement with the escapement wheel 12 and the clock-train will operate to
rotate the wheel 14. So long as the brush 16 is in contact with the rim 15, how-
ever, the coil 17 of the magnet 18 will be short-circuited and the circuit-breaker
will not operate. When the wheel 14 has rotated a sufficient distance to bring
the brush 16 on to the insulation portion of the wheel periphery between
the ends of the rim 15, the current in the secondary circuit will necessarily be
compelled to traverse the coil 17 of the magnet 18, and the latter will attract its
armature 24 and thus withdraw the latch 23 and permit the circuit breaker to
open, as is indicated in Figure 2.
Referring now to Figure 3 of the drawings, the main generating station or
source of power is represented by an alternating current generator A and the
main transmission conductors 1 and 1ª are protected from short circuits and
overloads by the circuit breaker mechanism B having an operative connection
with the conductor 1 by means of the transformer 3, the same as is indicated
in Figures 1 and 2. C and D represent two sub-stations respectively provided

page_text: with circuit breaking apparatus C and D similar to that already described,
and from each station, sub-feeders, to any desired number, may extend in
various directions for supplying either light or power or both for local consump-
tion. Two of such circuits c, and c2, c, are shewn as branching from the sub-
station C. The sub-feeder c is provided with a circuit breaker and the sub-
feeder with a circuit breaker C, which may be the same in construction and
mode of operation as already described. The number of sub-stations and the
number of sub-feeders branching from any one or all of them may be anything
desired, and my invention is therefore not limited in this regard.
I desire it also to be understood that my invention is also intended for use in
connection with polyphase circuits of any practical number of phases, and that
the protecting means described may be connected to each side of each circuit or to
two conductors of a three-phase circuit.
In utilising my invention in a system such as is generally indicated in Figure 3,
the time element of the circuit-breaker will open only at the end of a predeter-
mined interval of time after the time measuring mechanism begins to operate.
In order that the opening of each circuit may be rendered independent of all
the others, I propose to so set the circuit making and breaking element of
the time-measuring mechanism or device-this element, as shewn, being the
wheel 14 pertaining to each circuit breaker, that the time period which will
elapse before the breaker will act will be of different length from that of any
other controlling or dependent circuit. For example, each of circuit-breakers
and C may be set to open at an interval of, say, two seconds after the occurrence
of a local short-circuít; circuit-breakers C and D, after an interval of four
seconds, and circuit-breakers B, after an interval of six seconds. It will thus be
seen that should the trouble occur at any point other than at the main station,
the particular circuit where the trouble occurs will be opened before the circuit-
breakers at other points which are set for a greater time limit will have an
opportunity to open.
It will be understood that my invention is not limited to any specific time
measuring device or to any particular type of circuit-breaker, and that where
I have illustrated and described magnets and armatures, solenoids and movable
cores may be employed..
Dated the 22nd dor of December 1890
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C.,
Patent Agents for the Applicant.
Improvements in Systems of Electrical Distribution and Circuit-
breakers for Use therein.
I, LEWIS BUCKLEY STILLWELL, of Niagara Falls, New York, U.S.A., Electrical
Engineer, do hereby declare the nature of this invention and in what manner the
same to be performed to be particularly described and ascertained in and by
the following statement:-
My invention relates to systems of electrical distribution and to circuit-breakers
for use therein for protecting such systems from injuries resulting from short
circuits and overloads.
The object of my invention is to provide an effective means for localising
the interruption of service which, in electric power plants, is likely to be caused
by a short-circuit or overload upon one of the branch circuits of the system.

page_text: In large systems of electrical generation and distribution, it is usual to transmit
the electrical energy from the generating station to a plurality of sub-stations;
and from each sub-station energy is distributed for lighting and power purposes
in various directions by local feeder circuits.
If circuit-breakers or fuses of ordinary types be used, a short circuit upon
one of the feeder circuits radiating from a sub-station will frequently result in
a total interruption of service from that sub-station, and will sometimes result in
a total interruption of the service from all sub-stations which are supplied througli
the main transmission circuit, since it is liable to open not only the circuit-
breakers or fuses in the feeder circuit first affected, but also to open the circuit-
breakers or fuses through which the entire amount of power delivered to the sub-
station is conveyed, and in some cases even the circuit-breakers or fuses at the
main station.
According to my invention I so construct the circuit-breaker that a definite
period of time will elapse after the short-circuit is established before the circuit
breaker acts. This period of time being moreover entirely independent of the
quantity of current which flows in the circuit.
In applying these circuit-breakers to a system of electrical distribution com-
prising a generating station with a plurality of sub-stations and local feeder
circuits arranged from the sub-stations, I provide circuit-breakers in the various
circuits so arranged that if a short-circuit occurs on any particular line the
circuit breaker controlling that line shall operate before any of the circuit-
breakers between that line and the generating station can operate.
By this
means any branch or feeder which may become short-circuited will be opened with
certainty without any risk of cutting off the supply of power from other branches
or feeders of the system.
In the drawings accompanying the Provisional Specification
Figure 1 is a diagrammatic view of a circuit-breaker, constructed in accordance
with my invention, in its closed position.
Figure 2 is a similar view to Figure 1 shewing the circuit-breaker open.
Figure 3 is a diagram of a system of distribution provided with circuit-
breakers arranged according to my invention.
Referring now particularly to Figures 1 and 2 of the drawings, 1 is an
electric conductor forming one side of a circuit to be protected and including
the primary winding 2 of a transformer 3, one terminal of the secondary wind-
ing 4 of this transformer being connected to one terminal of a coil 5 of a magnet 6.
The armature 7 for the magnet is pivotally mounted upon a suitable bracket or
other support 8, and has an arm 7 extending beyond the point of support so as
to engage with a pin 9 projecting laterally from a substantially vertical rod 10.
The rod 10 is pivotally connected at its upper end to a holding pawl 11, the free.
end of which, when in the position shewn in Figure 1, engages with the single
tooth of an escapement wheel 12 of a clock train 13. The pawl is normally held
in this position by means of gravity and the action of a coiled spring 10 inter-
posed between a portion of the bracket 6 and an adjusting nut 10b on the lower
end of the rod 10. The clock train 13, when free to move, may be operated by
a spring or weight and regulated in any well-known manner so as to rotatė, at a
certain definite speed, a wheel or disc 14 the body of which is preferably formed
of insulating material and is provided with a conducting strip 15 which extends
over a portion of its periphery. A contact finger or brush 16 engages with the
periphery of the wheel 14 and constitutes the terminal for one end of the trans-
former secondary 4, and also for one end of the coil 17 of a magnet 18.
other end of the coil 17 and one end of the coil 5 are suitably connected together
and to the rim 15 of the wheel 14, by any suitable means.
The
The circuit-breaker proper may be of any suitable form adapted for auto-
matically opening an electric circuit. In the present case I have shewn it as
comprising a pair of stationary terminals 19, a bridging movable terminal. 20,
toggle levers 21, and a handle 22 moving the member 20 into engagement with

page_text: the terminals 19, and a latch 23 constituting an extension of the armature 24 of
the magnet 18.
It will be understood from the construction here illustrated and described, that
as long as the parts are in the position shewn in Figure 1 and the current in
the circuit does not rise above the amount for which the clock-train-releasing
mechanism is adjusted, there will be no movement of the clock-train or of the
circuit breaker. If, however, the current increases to such an amount as to
cause the magnet 6 to exert a pull upon the armature 7 sufficient to overcome the
action of gravity and that of the coiled spring 10%, the pawl 11 will be raised out
of engagement with the escapement wheel 12 and the clock-train will operate to
rotate the wheel 14. So long as the brush 16 is in contact with the rim 15, how-
ever, the coil 17 of the magnet 18 will be short-circuited and the circuit breaker
will not operate. When the wheel 14 has rotated a sufficient distance to bring
the brush 16 on to the insulation portion of the wheel periphery between
the ends of the rim 15, the current in the secondary circuit will necessarily be
compelled to traverse the coil 17 of the magnet 18, and the latter will attract its
armature 24 and thus withdraw the latch 23 and permit the circuit breaker to
open, as is indicated in Figure 2. The opening of the circuit necessarily
demagnetizes the magnet allowing the pawl 11 to drop, the wheel 12 con-
tinuing to revolve until the tooth again comes in contact with the pawl 11.
This resets the time element mechanism in its zero or initial position.
Referring now to Figure 3 of the drawings, the main generating station or
source of power is represented by an alternating current generator A and the
main transmission conductors 1 and 1ª are protected from short circuits and
overloads by the circuit breaker mechanism B having an operative connection
with the conductor 1 by means of the transformer 3, the same as is indicated
in Figures 1 and 2. C and D represent two sub-stations respectively provided
with circuit breaking apparatus C and D similar to that already described,
and from each station, sub-feeders, to any desired number, may extend in
various directions for supplying either light or power or both for local consump-
tion. Two of such circuits c, c and 3, are shewn as branching from the sub-
station C. The sub-feeder e is provided with a circuit breaker C2 and the sub-
feeder with a circuit breaker C, which may be same in construction and
mode of operation as already described. The number of sub-stations and the
number of sub-feeders branching from any one or all of them may be anything
desired, and my invention is therefore not limited in this regard.
I desire it also to be understood that my invention is also intended for use in
connection with polyphase circuits of any practical number of phases, and that
the protecting means described may be connected to each side of each circuit or to
two conductors of a three-phase circuit.
In utilising my invention in a system such as is generally indicated in Figure 3,
the time element of the circuit-breaker will open only at the end of a predeter-
mined interval of time after the time measuring mechanism begins to operate.
In order that the opening of each circuit may be rendered independent of all
the others, I propose to so set the circuit making and breaking element of
the time-measuring mechanism or device-this element, as shewn, being the
wheel 14 pertaining to each circuit breaker, that the time period which will
elapse before the breaker will act will be of different length from that of any
other controlling or dependent circuit. For example, each of circuit-breakers C
and C³ may be set to open at an interval of, say, two seconds after the occurrence
of a local short-circuit; circuit-breakers C and D¹, after an interval of four
seconds, and circuit-breakers B, after an interval of six seconds. It will thus be
seen that should the trouble occur at any point other than at the main station,
the particular circuit where the trouble occurs will be opened before the circuit-
breakers at other points which are set for a greater time limit will have an
opportunity to open.
It will be understood that my invention is not limited to any specific time

page_text: measuring device or to any particular type of circuit-breaker, and that where
I have illustrated and described magnets and armatures, solenoids and movable
cores may be employed.
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. In a system of electrical distribution consisting of a main supply circuit and
two or more subordinate or distributing circuits which receive energy from the
main circuit, an automatic circuit opening device controlling the main supply
circuit, and an automatic circuit opening device controlling one or more of the
subordinate distributing supply circuits, these circuit-breakers being severally
provided with time-measuring mechanisms so adjusted with reference to each
other that in case of a short-circuit upon a subordinate circuit, the circuit-breaker
controlling the subordinate distributing circuit must operate before the circuit-
breaker controlling the main circuit operates.
2. Circuit-breakers constructed and operating substantially as described with
reference to Figures 1 and 2 of the drawings accompanying the Provisional
Specification.
3. A system of electrical distribution provided with circuit-breakers arranged
to open on the lapse of different periods of time after a short-circuit occurs
according to their position in the system, substantially as and for the purpose
specified.
Dated the 10th day of Santember 1900
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham.