U.S. patent number 3,893,050 [Application Number 05/470,104] was granted by the patent office on 1975-07-01 for solenoid actuated circuit breaker operator.
This patent grant is currently assigned to Westinghouse Electric Corp.. Invention is credited to Louis N. Ricci, John G. Salvati.
United States Patent |
3,893,050 |
Salvati , et al. |
July 1, 1975 |
Solenoid actuated circuit breaker operator
Abstract
A circuit breaker operating mechanism is provided having a frame
mountable upon the face of a circuit breaker. A saddle assembly
engages the operating handle of the circuit breaker and is
slideably attached to the frame. A pair of solenoids are
transversely mounted at opposite ends of the frame and are linked
to the saddle assembly by two pairs of core and lever arm
assemblies making lost motion connections to the saddle assembly.
Energization of either solenoid applies force through the core and
lever arm assemblies to the saddle assembly in a direction parallel
to the direction of movement of the saddle assembly at points
spaced away from the centerline of the saddle assembly.
Inventors: |
Salvati; John G. (Beaver Falls,
PA), Ricci; Louis N. (Beaver Falls, PA) |
Assignee: |
Westinghouse Electric Corp.
(Pittsburgh, PA)
|
Family
ID: |
23866285 |
Appl.
No.: |
05/470,104 |
Filed: |
May 15, 1974 |
Current U.S.
Class: |
335/1; 335/69;
335/184 |
Current CPC
Class: |
H01H
71/68 (20130101); H01H 51/12 (20130101); H01H
3/46 (20130101); H01H 71/04 (20130101); H01H
2071/665 (20130101) |
Current International
Class: |
H01H
71/04 (20060101); H01H 3/00 (20060101); H01H
3/28 (20060101); H01h 003/02 () |
Field of
Search: |
;335/1,2,69,168,177,184 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Broome; Harold
Attorney, Agent or Firm: Elchik; W. A.
Claims
We claim as our invention:
1. An operating mechanism for remotely controlling a circuit
breaker, said operating mechanism comprising:
a. a frame mountable in association with a circuit breaker, said
circuit breaker having an operating handle,
b. a saddle assembly adapted to engage the operating handle of the
associated circuit breaker, said saddle assembly activating the
operating handle of the circuit breaker upon movement of said
saddle assembly,
c. means attached to said frame for supporting said saddle
assembly, said saddle assembly supporting means permitting linear
longitudinal movement of said saddle assembly with respect to said
frame through sufficient distance to actuate the associated circuit
breaker operating handle from one operating position to another
operating position,
d. solenoid means, said solenoid means comprising movable core
means,
e. means for energizing said solenoid means to cause said core
means to move from one operating position to another operating
position; and,
f. linkage means connecting said saddle assembly and said core
means, said linkage means transmitting force from said core means
to said saddle assembly through lost motion connections at a
plurality of points spaced away from the centerline of said saddle
assembly, said saddle assembly moving said breaker handle from one
operating position to another operating position in response to
movement of said core means.
2. An operating mechanism as described in claim 1, wherein said
solenoid means comprises two solenoids having movable cores, said
solenoids being disposed in parallel at opposite ends of said
frame, and transverse to said frame.
3. An operating mechanism as described in claim 1, wherein said
support means comprises a pair of guide rails disposed on opposite
sides of said frame, each of said guide rails including a
longitudinal slot parallel to the direction of movement of said
saddle assembly.
4. An operating mechanism as described in claim 3, wherein said
saddle assembly comprises a generally U-shaped saddle member
including a base element and two projecting side elements, said
base element having a plurality of transverse slots and a holding
structure, said holding structure being adapted to engage the
operating handle of a circuit breaker, said saddle assembly having
a plurality of transverse rods, each of said rods projecting
through both of said side elements and each of said transverse rods
being slidably attached to said guide rails through said
longitudinal slots.
5. An operating mechanism as described in claim 4, wherein said
linkage means comprises four lever arms, each of said lever arms
being pivoted at one end thereof to one of said movable cores; each
of said lever arms being provided at another end with a pin, said
pin engaging one of said transverse slots of said saddle assembly,
to provide lost motion connections to said saddle assembly and to
transmit force to said saddle assembly in a direction parallel to
the direction of movement of said saddle assembly, said force being
applied at points spaced away from the centerline of said saddle
assembly; and each of said lever arms being pivotally attached
intermediate their two ends to said frame.
6. An operating mechanism as in claim 1, wherein said frame is
removably mountable upon the face of a circuit breaker.
7. An operating mechanism as in claim 1, wherein a limit switch is
provided to deenergize said solenoid means.
8. An operating mechanism as in claim 7, wherein a limit switch
actuating means is attached to said saddle assembly, said limit
switch actuating means being operative to actuate said limit switch
when said saddle assembly has moved a sufficient distance to
actuate the handle of an associated circuit breaker to a selected
operating position.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates in general to operators for circuit breakers
and more particularly to external operators with solenoid driven
mechanisms.
2. Description of the Prior Art
In many applications it is desirable to operate circuit breakers
from a remote location. The breaker may be located in an
inaccessible or out of the way location, or many circuit breakers
may be required to be operated from one central station. One means
for accomplishing this is to use a motor to drive a mechanism for
actuating the circuit breaker. However these motor driven operating
mechanisms often require gear trains and other complex components.
The cost and maintenance requirements of such mechanisms render
them impractical for smaller breakers. In addition, the time
required for a motor to drive the mechanism to an extent necessary
to actuate the circuit breaker is often objectionable.
Many of these problems can be alleviated by using a solenoid to
drive a mechanism for operating the circuit breaker. The solenoid
mechanism is simpler, cheaper, and requires less maintenance than a
comparable motor driven mechanism. In addition solenoids can
operate much more rapidly. However, the very speed of a solenoid
driven mechanism often presents a problem, for in rapidly actuating
a circuit breaker the shock created by such operation is often
sufficient to damage or break the operating handle of the breaker.
Thus, it is desirable to achieve high speed operation of the
circuit breaker while at the same time protecting against damaging
shock.
In many applications it is desirable to have a circuit breaker
operator which can be removed from its associated circuit breaker
and mounted upon another circuit breaker of the same or similar
type. The mechanism for such an operator must be compact,
especially for actuating small circuit breakers, but must produce
sufficient force and throw movement to actuate such circuit
breakers.
SUMMARY OF THE INVENTION
The invention provides an operating mechanism for remotely
controlling a circuit breaker. The mechanism includes a frame
mountable in association with the circuit breaker and a saddle
assembly engaging the operating handle of the associated circuit
breaker. The saddle assembly is movably supported by the frame and
actuates the operating handle of the circuit breaker from one
operating position to another. Solenoid means are provided
including core means and means for energizing the solenoid means to
cause the core means to move from one operating position to
another. Linkage means connecting the saddle assembly and the core
means transmits force from the core means to the saddle assembly
through lost motion connections at a plurality of points spaced
away from the centerline of the saddle assembly, causing the saddle
assembly to move the operating handle of the associated circuit
breaker from one operating position to another in response to
movement of the core means. By applying the force to the saddle
assembly at points spaced away from the centerline of the saddle
assembly, throw movement sufficient to operate the circuit breaker
is obtained with a compact mechanism. The transmission of force
through the linkage mechanism and the saddle assembly rather than
directly to the operating handle of the circuit breaker provides
shock absorbing capability preventing damage to the circuit breaker
handle.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the circuit breaker operating
mechanism mounted upon the face of a circuit breaker;
FIG. 2 is a perspective view of the circuit breaker operating
mechanism with the indicator flag removed and with the cover, limit
switch assembly, and guide rail partially cut away;
FIG. 3 is a perspective view of the circuit breaker operating
mechanism with the cover, limit switch assembly, and actuator
assembly removed and with selonoids and frame partially cut away to
show the construction of the core, lever arm, and saddle
assemblies;
FIGS. 4, 5 and 6 are front elevational views partially cut away to
show the core, lever arm, and saddle assemblies and the indicator
flag positions when the operating mechanism is in open, tripped,
and closed positions respectively;
FIGS. 7, 8 and 9 are side elevational views partially cut away to
show the operation of the limit switch and actuator assemblies when
the operating mechanism is in open, tripped, and closed position,
respectively;
FIG. 10 is a side elevational view of the operating mechanism and
associated circuit breaker showing the operating mechanism swung
upward in a disengaged position;
FIG. 11 is a schematic wiring diagram showing the electrical
connections to the operating mechanism when operated from a direct
current supply; and
FIG. 12 is a schematic wiring diagram showing the electrical
connections to the operating mechanism when operated from an
alternating current supply.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, in FIG. 1 there is shown a
perspective view of a circuit breaker operating mechanism 10
constructed according to the principles of the present invention. A
frame 12 is constructed of high permeability magnetic material,
such as ingot iron. Guide rails 14 are mounted along each side of
the frame 12, each guide rail including a longitudinal slot 16.
Riding in these slots 16 is a saddle assembly 18 consisting of a
base 20 and side elements 22. Roller rods 24, 26 extend transverse
to the saddle assembly through each side element 22 and through the
longitudinal slots 16 in each of the side rails 14. The roller rods
24, 26 are secured in the slots 16 by C-rings 28. The saddle
assembly 18 also includes two pairs of transverse slots 32, 34
shown more clearly in FIG. 3 and a holding structure consisting of
two handle pins 38, as shown in FIGS. 7, 8 and 9. At opposite ends
of the frame 12 are mounted a pair of solenoids 40, 42 parallel to
each other and transverse to the frame 12. These solenoids are
wound upon nylon bobbins 44, 46 shown in FIG. 3 which are held by
the frame 12 thus attaching the solenoids to the frame 12.
The interior of each bobbin 44, 46 is a cylindrical volume
containing two movable cores 48a and 48b, 50a and 50b made of high
permeability magnetic material. These cores are free to slide
within the interior of the bobbins 44, 46. When the cores 48a and
48b are positioned at the outer extremity of the interior of the
bobbin 44 as shown in the upper solenoid 40 of FIG. 6, they define
a working air gap 52.
As shown in FIG. 4, each core 48a and 48b, 50a and 50b is pivoted
to a lever arm 56a and 56b, 58a and 58b by means of a pin 49a and
49b, 51a and 51b. Each lever arm is also pivoted to the frame 12 by
means of hex pins 60a and 60b, 62a and 62b. The end of each lever
arm which is opposite the pivot pin 49a and 49b, 51a and 51b has
attached to it an engaging pin 68, 70. Each engaging pin extends
through one of the transverse slots 32, 34 in the saddle assembly
18 forming lost motion connections between the lever arms and the
saddle assembly.
In FIG. 2 there is shown a limit switch assembly consisting of a
limit switch 74 attached to a sheet metal switch mounting bracket
78 secured to the frame 12 by means of screws 45. The limit switch
74 is activated by movement of a plunger 76 which extends through
the limit switch in a direction parallel to movement of the saddle
assembly.
FIG. 7 shows a support column 82 attached to the base 20 of the
saddle assembly. This support column extends slightly above the
frame 12 but not touching the limit switch mounting bracket 78. A
U-shaped actuator bracket 86 of sheet metal is attached to the top
of the support column 82. Flat-head pins 88, 90 extend through each
end of the U-shaped bracket with their heads facing inward,
cooperating with the plunger 76 of the limit switch 74. These pins
are adjustably shock mounted to the U-shaped bracket by means of
springs 92, 93 and nuts 94 which engage the threaded shaft of the
flat-head pins 88, 90.
A cover 104, shown in FIG. 1, formed of sheet metal is removably
attached to the operating mechanism 10 by screws engaging support
posts 103. These posts are secured to the frame 12 by the
engagement of threaded ends 122 of the post 103 in holes tapped
into the frame 12, as in FIG. 7.
The hex pins 60a, 60b and 62a, 62b extend through holes 126 in the
cover 104. An indicator flag 106 is affixed to hex pin 60a as shown
in FIG. 4. Inscribed upon the indicator flag 106 are the words ON,
OFF, and TRIP. As the saddle assembly 18 moves from its upper
position, as in FIG. 6, corresponding to a breaker state of ON
through an intermediate position, as in FIG. 5, corresponding to a
tripped condition of the breaker to its lower position, shown in
FIG. 4, corresponding to an OFF position of the breaker, the hex
pin 60a rotates in the frame 12. The angular displacement of the
hex pin 60a as the breaker moves between its various operational
states causes the corresponding legend inscribed on the indicator
flag 106 to be visible from the outside of the cover 104 through a
window 105 cut into the sheet metal cover 104. Thus it is possible
for an observer to determine the operational state of the
associated breaker 108 without removing the cover.
In operation the mechanism is associated with a circuit breaker 108
having a molded case 110 and an operating handle 112, such as the
type KB breaker. As shown in FIG. 1, the mechanism 10 is mounted
upon the face 114 of the circuit breaker case 110. Screws 116 are
used to secure the mechanism to mounting brackets 118 affixed to
the case of the breaker 108 the brackets 118 are best shown in FIG.
2. In mounting the mechanism the saddle assembly 18 is positioned
so that the handle pins 38 of the holding structure straddle the
operating handle 112 of the breaker 108, as shown in FIGS. 7, 8 and
9.
In FIGS. 6 and 9 the saddle assembly is shown at the upper
extremity of its travel. With the saddle assembly in this position
the upper lever arms 56a and 56b are situated so that their
engaging pins 68 are at the outer extremities of the upper
transverse slots 32 of the saddle assembly. Also the cores 48a and
48b of the upper solenoid 40 are at the outer extremity of the
bobbin 44. The working air gap 52 is thus at its largest size.
In contrast, the engaging pins 70 of the lower lever arms 58a and
58b are at the inner extremities of the lower transverse slots 34
of the saddle assembly. The cores 50a and 50b of the lower solenoid
42 are correspondingly positioned in contact with one another in
the interior of the space within the lower bobbin 46. The working
air gap 54 of the lower solenoid 42 is effectively eliminated.
Energization of the upper solenoid 40 produces a strong magnetic
field within the interior of the bobbin 44 upon which it is wound.
This field exerts force upon the movable cores 48a and 48b or the
upper solenoid 40 drawing them toward one another within the
interior of the bobbin 44. As the cores 48a and 48b approach one
another, the upper lever arms 56a and 56b pivot about the hexagonal
pins 60a and 60b transmitting force to the engaging pins 68 which
in turn exert a downward force upon the saddle assembly 18. As the
cores 48a and 48b continue to move toward the center of the bobbin,
the lever arms and hexagonal pins continue to rotate within the
frame 12 and the saddle assembly 18 travels downward, assuming
successively the positions shown in FIGS. 5 and 4. As the saddle
assembly 18 moves downward it exerts force on the lower engaging
pins 70 which in turn cause the lower lever arms 58a and 58b and
the hexagonal pins 62a and 62 b to pivot and drive the movable
cores 50a and 50b of the lower solenoid 42 to the outer ends of the
lower bobbin 46. Since the operating handle 112 of the circuit
breaker 108 is engaged by the holding structure 36, as the saddle
assembly 18 travels downward the operating handle also travels
downward actuating the circuit breaker to a new operational
state.
As the saddle assembly 18 moves downward, the attached support
column 82 and actuator bracket 86 also move downward, as shown in
FIGS. 9, 8 and 7. The flat-head pin 88 comes in contact with the
limit switch plunger 76 depressing the plunger and actuating the
limit switch 74. The spring 92 and nuts 94 are adjusted in such a
manner that sufficient force to move the plunger 76 and operate the
limit switch is produced when the saddle assembly 18 has moved a
distance sufficient to move the operating handle 112 of the breaker
108 to a new operational state. The spring 92 also serves to absorb
shock and prevent damage to the plunger 76. Actuation of the limit
switch serves to deenergize the solenoid 40. At this point the
operating mechanism 10 has succeeded in transferring the associated
circuit breaker 108 from one operational state to another.
With the operating mechanism 10 engaged upon a circuit breaker 108
and the breaker in the OFF condition the saddle assembly 18 is in
the position as shown in FIG. 4. To operate the breaker from the
OFF position to the ON position, the ON switch 98, FIG. 11, is
actuated. This results in voltage being applied to the lower
solenoid 42. Magnetic flux is thereby produced with flows in the
magnetic circuit defined by the air gap 52, the cores 50a and 50b,
the side members 11 of the frame 12 and the cross members 13 of the
frame 12. This flux produces a strong attractive force between the
cores 50a and 50b acting across the air gap 54. This force causes
the cores 50a and 50b to move toward the center of the bobbin 46
and toward one another, causing rotation of the lever arms 58a and
58b and the hex pins 62a and 62b. As the lever arms 58a and 58b
rotate, the attached engaging pins 70 act against the saddle
assembly 18 driving the saddle assembly 18 upward toward the
position shown in FIG. 6. Since the operating handle 112 of the
circuit breaker 108 is engaged by the handle pins 38 it also is
moved, thus actuating the circuit breaker 108 to the ON state. As
the saddle assembly 18 moves upward, force is applied to the
engaging pins 68 causing rotation of the lever arms 56a and 56b,
driving the cores 48a and 48b to the outer extremities of the
bobbin 44, and rotating the hex pins 60a and 60b. The pin 60a
rotates the indicator flag 106, causing the word ON to become
visible through the window 105 in the cover 104. As the saddle
assembly 18 travels upward the attached support column 82 and
actuator assembly 84 also move upward. When the saddle assembly
reaches the upper extremity of its travel, the flat-head pin 90
comes in contact with the plunger 76 of the limit switch 74. The
plunger is driven upward, actuating the limit switch and opening
the circuit supplying electrical energy to the solenoid 42. It can
be seen that the selective alternate energization of the solenoids
40 and 42 will result in transferring of the associated circuit
breaker from one operational state to another operational
state.
FIG. 11 is a diagram showing electrical connections which may be
used to operate the mechanism. A power source supplying 125 volts
DC is applied to the input terminals 96. Two switches 98 and 100
are connected as shown to provide for alternate energization of the
two solenoids 40 and 42. These switches are preferably of the
momentary contact pushbutton type. The limit switch 74 is connected
as shown between the ON and OFF switches 98 and 100 and the two
solenoids 40 and 42. With the limit switch in the position as shown
in FIG. 11 the saddle assembly is in the OFF position or the lower
position as shown in FIG. 6. In order to transfer the mechanism and
the associated breaker from OFF position to the ON position, that
is, to move the saddle assembly 18 to its upper position as shown
in FIG. 4, the ON switch 98 is depressed. As can be seen in FIG. 11
this applies 125 volts DC to the ON solenoid 42. This action
results in a magnetic field being produced in the ON solenoid 42
causing the movable core 50a and 50b to move toward the center of
the bobbin 46. The lever arms 58a and 58b and hex pins 62a and 62b
rotate, driving the saddle assembly 18 to its upper position. This
results in movement of the actuator bracket 86 causing flathead pin
90 to come in contact with the plunger 76 and actuate the limit
switch 74 to its alternate position A in FIG. 11. The power supply
is no longer connected to the ON solenoid 42.
The mechanism can also be operated from an AC power source as shown
in FIG. 12. The only requirement is the addition of full wave
rectifier bridge circuits 120a and 120b connected as shown FIG. 12.
These circuits serve to transform the alternating current to direct
current in a well known manner and apply the direct current to the
solenoids 40 or 42.
The mechanism may also be operated from a higher voltage supply
source by the addition of a suitable resistor 102 as shown in FIGS.
11 and 12. The value of the resistor will depend on the voltage of
the power source from which it is desired to operate the mechanism
and the impedance of the solenoids 40 and 42. For example, if it is
desired to operate the mechanism from a 250 volt DC supply the
resistance value of the resistor 102 should be equal to the
resistances of the solenoids 40 and 42. Correspondingly, if it is
desired to operate the mechanism from a 240 volt AC supply a
resistor should be chosen with an impedance equal to the impedances
of the solenoids 40 and 42.
Manual operation of the circuit breaker can be accomplished with
the operating mechanism 10 in place by the action of a pair of
wrench levers 126 and 127, FIG. 1. Each lever includes a hexagonal
shaped hole which is fitted over the hex pins 60a or 60b. Lever 126
includes a pin 130 extending perpendicular to the plane of the
levers 126 and 127 through a corresponding slot 128 in lever 127.
Applying manual force to the pin 130 in an upward or downward
direction results in the rotation of hex pins 62a and 62b. This in
turn causes movement of the lever arms 56a and 56b transmitting
motion to the saddle assembly 18 and actuating the circuit breaker
108.
The operating mechanism 10 can be easily removed from the
associated circuit breaker 108 by removing the four screws 116 and
lifting the operating mechanism away from the face of the circuit
breaker. Alternatively, the mechanism can be temporarily disengaged
from the circuit breaker by removing the bottom two of the screws
116 and swinging the mechanism upward and away from the face of the
breaker as is shown in FIG. 10.
A requirement of an operating mechanism for smaller molded case
circuit breakers is that the structure be compact. In the present
mechanism compactness of design is achieved by providing that force
be transmitted from the lever arms to the saddle assembly at a
point which ensures maximum linear travel of the saddle assembly
18. This is done by extending the transverse slots 32 and 34
laterally to the extreme edge of the saddle assembly 18 with
respect to the centerline of the saddle assembly.
The base member 20 of the saddle assembly lies in a plane
substantially parallel to the circuit breaker face 114. However, it
has a natural tendency to rock out of this plane as the saddle
assembly 18 moves from one extreme of its travel to the other. This
is due to the action of the slanted faces of the circuit breaker
operating handle 112 upon the handle pins 38 of the holding
structure. Any excessive rocking motion would tend to cause
mechanical binding of the saddle assembly with respect to the frame
and preventing motion of the saddle assembly 18. This rocking
motion is prevented by the transverse rods 24 and 26 which act as
roller bearings in the longitudinal slots 16 of the side rails
14.
The build-up of force upon energization of a solenoid is extremely
rapid, causing a correspondingly high acceleration of the cores
48a, 48b or 50a, 50b. The lever arms 56a, 56b and 58a, 58b and the
connections between these lever arms and the cores and the saddle
assembly 18 serve to absorb the shock of the rapid acceleration
thereby preventing damage to the circuit breaker operating handle
112. They perform a similar function when the saddle assembly 18
reaches the end of its travel. As the core pairs meet inside their
respective bobbins additional shock is absorbed that might be
directed on the breakers operating handle.
It will be seen therefore that there has been disclosed an
operating mechanism for molded case circuit breakers which is of
compact design and simple construction.
* * * * *