Note: Descriptions are shown in the official language in which they were submitted.
2092027
950-414
OPERATING MECHANISM USABLE WTTH A VACUUM INTERRUPTER
This invention relates to an operating mechanism usable
in a circuit interrupter of the type utilized in high power
distribution systems and particularly those interrupters that
may be automatically operated to permit energization or de-
energization in response to abnormal line conditions, i.e.
excessively high line current, on an automatic local basis, or
upon command from a remote control center.
The utilization of vacuum interrupters to provide fast,
low, arc energy interruption with long contact life requires
essential, precise mechanical operating characteristics.
Contact velocities, minimum rebound on the closing and opening
operations, high contact pressure in a closed state and high
separation forces required on opening are all desirable.
Often a solenoid was directly coupled through a pre-
loaded spring member to drive vacuum interrupter contacts) to
a spring loaded closed position while simultaneously extending
the opening springs) to a fully charged state. For such a
device see U.S. Patent No. 5,175,403, issued December 29, 1992
to Sidney R. Hamm and Ronald A. Wainio (the latter being one
of the joint inventors of the present invention) and assigned
to the common assignee of this invention. In some instances,
solenoids of this type were designed for a specific voltage
rating, thus, making them susceptible to system voltage
fluctuations directly affecting the contact close operation.
The directly driven contact member driven through a trip free
linkage to close may be released to open a partially charged
1
20902?
opening spring due to contact make occurring prior to the
fully closed position being reached. Also, inherent in the
direct contact drive system to close condition is a prolonged
delay in reaching the full required contact pressure.
Other prior art mechanisms can be found in U.S. Patent
No. 3,526,715 issued to K.H. Date on September 1, 1970 and in
U.S. Patent No. 2,804,521 issued to Anthony VanRyan et al on
August 27, 1957. In the opening sequence of the vacuum
interrupter contacts in the above described prior art
mechanisms, full contact pressure is not maintained to contact
separation adding to the susceptibility of contact welding.
Contact separation forces are the resultant of the static
opening spring forces and any impact energy. The higher the
opening energy the more difficult it is to control contact
rebound on opening. Some methods used to control rebound on
opening were dashpots, shock absorbing materials and
mechanical catches. In such prior art, the static and kinetic
opening energy was variable, additionally, they utilized
mechanical devices to catch and hold the contacts from
rebounding to a closed condition after opening; dash pots and
shock absorbing materials were used to dissipate the kinetic
opening energy of the contact rod assembly. Mechanisms
utilizing a variable closing energy source contend with
variable contact closing speed and energy.
SUMMARY:
The present invention strives to solve the aforementioned
situations by providing an operating mechanism designed to
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CA 02092027 2003-05-26
77326-45
overcome each of the problems created in the interrupter
environment, by a opez~atin.g mechanism that :is designed to
solve problem: such a:!.: (a) providing a consistent, high
force requirement at contact separation; (b) eliminating
contact rebound after opening; (c) eliminating excessive
contact overtravel on opening; (d) eliminating opening
spring energy being rE:leased from a partially charged state;
(e) providing a closing energy consistent and independent of
any variable charging means; (f) providing a minimal time
1C delay in reaching full contact pressure after contact make;
and (g) eliminating contact rebound after contact make on
closing. All of these mechanism attributes would provide
optimum characteristics for an operating mechanism of the
type contemplated by the present invention for use in a
vacuum interrupter and would permit superior performance of
the switchgear control.:l.ed by it. For example, the prior art
made contact and then .increased or loaded the contact
spring. In tree preseni~: =invention's device, the spring is
constantly in a pre-loaded state before contact is made and
the spring serves a dual function in that. the spring
provides closing energ,~:~ to move the contact as well as
provide contact pressure when contacts are closed.
According to a broad aspect, the invention
provides an o~~erating rnE:chanism for producing controlled
linear motion wherein said controlled linear motion is
utilized to independently open and close linearly moveable
electrical contacts, s:~s.d rnechanpsm comprising: means f:or
producing a dynamic mot:i.ve force for driving said operating
mechanism; a first stal;ic energy storage means for opening
the electrical contact,:; a second ;stati.c energy storage
means for closing the electrical contacts and for exerting a
constant force on the ~.~:oritact.s from an instant of contact
make to an instant of ~:~ontact separation; means for
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CA 02092027 2003-05-26
77326-45
releasing said static energy of said first and said second
static energy storage rnean.s to carry out the opening and
closing of said contacts; and means for preloading said
first static energy st:orin.g means prior to releasing the
~~ static energy of the second static energy storage means.
According to another aspect, the invention
provides in a high voltage electrical 'Vacuum interrupter
having at lea;~t one fixed and one moveable contact means, an
operating mechanism comprising: means for providing a
linear motive force for driving said operating mechanism;
mechanical means for translating said :Linear motive force to
a controllable functie:n<~l means capable of operating said
moveable contact means within pre-determined parameters"
wherein a constant for~~e is provided between said vacuum
interrupter contacts during a closed state, and wherein said
mechanical means compri.;~es at least one compression spring;
a multi-link ~>ystem that: p:rovi.des a high contact separation
force and prez~ents contact rebound after the contacts are
opened, wherein said mufti-link system includes at least one
tension spring; and me~ms :Eor discharging said at least one
tension spring such th~:~t: the discharging of s<~id at lea:~t
one tension spring causes the at least one compression
spring to become re-armed.
According to a further aspect:, the invention
provides an operating mechanism for opening and closing
linear moving members ~::~rr single or multiphase circuit
interrupters, said mec~narri;~m cornprisi_ng: a first spring for
exerting a constant closing pressure on the interrupter
contacts from an instant contact is made between said
interrupter contacts t~::> an instant said interrupter contacts
undergo contact separa°~ion; a mufti-linked mechanical system
for providing high contact separation farces and for moving
3a
CA 02092027 2003-05-26
77326-45
the interrupter contacts from a closed position to an open
position with. precise, controlled movement. thus minimizing
opening rebound and cc:~ntact opening overtravel; and a second
spring that drives the mufti-linked system to open the
contacts.
Thu;~, the present invention provides a stored
spring energy operatir~.g mechanism to open and close linear
moving member: such a~; inter.rupter contacts on single or
multiphase circuit interrupters. The mechanism includes a
spring driven mufti-linl~ed system moving the interrupterr
contacts open or closed with precise, controlled movement to
minimize opening rebound, closing rebo°and and contact
opening overtravel. Such
3b
2~920~~
a multi-linked system provides high contact separation forces
and movement to a specific contact gap while simultaneously
loading a closing spring to it's fully charged and latched
state. This mechanism provides and maintains full contact
pressure from the instant of contact make to the instant of
contact separation. A key to providing consistent opening and
closing operations is the use of stored spring energy for both
make and break functions and the sequential scheme to charge
the opening spring prior to releasing a precharged closing
spring and subsequent contact closing. These and other
advantages will become apparent when the specification is read
in conjunction with the attached drawings, wherein similar
parts are designated by similar numerals.
BRIEF DESCRIPTION OF THE DRAWINGS'
FIG. 1 is a vertical elevational view of the exterior of
a single phase vacuum recloser utilizing an operating
mechanism of the type contemplated by the present invention;
FIG. 2 is a top plan view of the recloser shown in FIG.
1;
FIG. 3 is a vertical elevational view of substantially
all of the operating mechanism, vacuum interrupter, and motive
power means normally positioned within a tank of the type
shown in FIG. 1;
FIG. 4 is a fragmentary end view of the operating
mechanism taken along line 4-4 in FIG. 3;
FIG. 5 is a plan view of the operating mechanism removed
from the tank of FIG. 1;
4
2~9202'~
FIG. 6 is an end elevational view taken along line 6-6 of
FIG. 5;
FIG. 7 is the opposite end elevational view taken along
line 7-7 of FIG. 5;
FIG. 8 is a partial backside elevational view of the
operating mechanism as viewed along line 8-8 of FIG. 5;
FIG. 9 is a frontal elevational view of the mechanism
taken along line 9-9 of FIG. 5;
FIG. 10 is an elevational view in partial section taken
along line 10-10 of FIG. 5;
FIG. 10A is an elevational view in partial section,
substantially identical to FIG. 10, except that in this view
the mechanism is shown in the tripped open position with the
toggle latch plate assembly, shown in FIGS. 11, 11A and 11B,
is shown in the latched position by the plunger toggle lever
assembly, shown in FIGS. 15, 15A.;
FIG. lOB is an elevational view in partial section,
substantially identical to FIG. 10, except that those denoted
components are shown in the open position with the toggle
latch plate assembly, shown in FIGS. 1l, 11A and 11B, is shown
in the down reset position;
FIG. 11 is a vertical front view of the toggle latch
plate assembly;
FIG. 11A is a top plan view taken along line 11A-11A in
FIG. 11;
FIG. 11B is a fragmentary partial section of the cam-
latch adapted for engagement with latch assembly shown in FIG.
12;
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FIG. 12 is a latch assembly adapted for engagement with
the cam latch shown in FIG. 11B;
FIGS. 13, 13A is a top plan view and a front elevational
view of a pair of riveted links forming a yoke-like assembly;
FIGS. 14, 14A is an end view and a front elevational view
of the closing shaft assembly;
FIGS. 15, 15A is an end view and a front elevational view
of the plunger toggle lever assembly;
FIG. 16, 16A is a front elevational view and a side
elevational view of the rod and connector assembly having a
partially loaded spring, shown schematically, at the upper end
of the rod, and retained on said rod by a centrally apertured
shallow cup which is secured along the rod,
FIG. 17 is a partial fragmentary view of the linkage
between the flattened upper end of the drive rod of a pot coil
motive force and the mechanism main linkage;
FIG. 18 is the vacuum contact movable rod flattened at
its upper end and fastened to the narrow end of the yoke-like
assembly shown in FIGS. 13, 13A; and
FIG. 19 is a partial fragmentary elevational view of the
toggle latch plate assembly and "D"-shaped latch, with its
associated links and rods, as seen from its backside, contra
to the view shown as the frontside in FIG. 10.
DETAILED SPECIFICATION:
Referring to the drawings, and particularly FIGS. 3
through 18, there is illustrated a linear operating mechanism,
6
2Q9~02'~
generally designated 20, adapted for use with a single phase
high voltage circuit interrupter device 22 positioned within
an electrical power distribution system. The major components
of such an interrupter device 22 include a tank 24; a head
assembly 26, enclosing the operating mechanism 20 (the primary
contribution of the present invention); the head 26 also
carrying the insulated bushings 28,30. The tank 24 also
externally carries an electronic controller 32 and mounting
flanges 36, while the interior volume of the tank is filled
with transformer type oil, to a level substantially indicated
by the dashed line 34, as is well known in the art. Being a
supplier to public utilities, the assignee and the inventors
abide by the rules relating to "SCADA" - defined as: remotely
controlled "Supervisory Control and Data Aquisition". By
following the teachings and requirements of SCADA a utility
can by remote radio signal interrogate and/or change device
status.
Thus, major elements of the interrupter 22 controlled by
the operating mechanism 20 of the present invention include: a
source of motive power, i.e., a pot coil assembly 38 accepting
a plunger 40 and connecting rod 42; an opening and closing
solenoid contactor 44; a vacuum interrupter 46 having
associated support members 48; a rod 50 and connector 52
assembly provide spring-loaded linear movement through a
sealed bellows (not shown) for the contacts in the vacuum
interrupter 46; and a current transformer (not shown) for
sensing the line current.
7
209~0~7
The closing solenoid contactor 44 is coupled to operating
mechanism 20 through screws 54 and an elongated insulated link
56, with the contactor 44 being mechanically driven to
momentarily energize pot coil 38 to provide an upward charging
motion through plunger 40 and rod 42. The rod 42 is flattened
as at 43 and apertured to accept pin 58 (see FIG. 17 for
detail). The rod 42 is moved to the position shown in FIG. 3
followed by immediate de-energization of coil 38. Operating
mechanism 20 coupled through pin 60 to the flattened end 51 of
rod 50 and connector 52 drives the vacuum interrupter 46
contacts to the open or closed positions, as is known in the
art. The current transformer senses current levels passing
through the interrupter/recloser sending a proportional signal
to an electronic control 32, shown generally in FIGS. 1, 2,
which initiates trip and close signals, which shall be
discussed further hereinafter.
To carry out the proposed solutions set forth herein-
above to the problems facing the utilities, please refer to
FIGS. 4-19 which discloses the operating mechanism 20 which is
the subject matter of the present invention. The discussion of
the vacuum interrupter 46, the pot coil 38, the solenoid
contactor 44 set forth above is for the purpose of providing
an environment in which the present invention can be utilized.
While a single phase high voltage interrupter/recloser is
described, it must be recognized that the operating mechanism
can be also readily made available for use with multi-phase
circuits, and additionally it also can be utilized in other
8
2~9242~
environments where positive linear actuation within designated
parameters is required.
The operating mechanism 20 is generally supported on a
round apertured plate 70 with a pair of centrally disposed
spaced vertically disposed brackets or wall-like members 72,
74 each having an outwardly directed apertured flange 73, 75,
respectively, on which the wall-like members are mounted on
plate 70 and retained thereon by carriage bolts 76.
It will be appreciated that while the description below
discusses various links, pins and levers in the singular, in
actuality, in most instances, there are a pair of elements
acting in parallel on opposite sides of the centerline between
the pair of brackets or wall-like members 72, 74. This
balances the load on the mechanism as well as providing
multiple points of access to particular forms of motion, i.e.,
linear, rotary and arcuate.
One of the various assemblies associated with this
mechanism is the flux tripper assembly 80 which includes a
stepped plate 82 mounted on spacers 84 by screws 86; with
plate 82 supporting electromagnetic release devices FT-1 TRIP
designated 90 and FT-2 RE-CLOSE designated 92. Devices 90, 92
are used to sequence the mechanism 20 via the electronic
control logic 32. All of the associated linkage, namely, 100,
102, 104, 106, 108, 110, 58, 122 and 112A are the actuating
mechanism linkage for the closing solenoid contactor 44. It is
an over toggle-type mechanism coupled through pin 58 to the
toggle latch plate assembly 120 which drives spring 122,
bracket and pin assembly 102 through an over-center position
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of lever assembly 100 to open or close the closing solenoid
contactor 44. The contactor 44 would be in the open position
with the linkage as shown in FIG. 10.
Referring once again to FIGS. 8 - 19, which depicts the
mechanism 20, disposed within the bracket assembly formed by
the spaced walls 72, 74, in a closed position (the contacts in
the vacuum interrupter 46 are closed). As best seen
schematically in FIG. 10 and FIGS. 16-16A, the spring F is
retained at its upper end 124 in a fixed inverted centrally
apertured 126 cup-like member 128. As seen in FIGS. 16, 16A
and FIG. 3, the lower end 130 of the spring F rests within a
second cup-like member 132 that is secured along rod 50.
Member 132 is accepted piston-like telescopically within
chamber 134 of the enlarged third cup-like member 136.
Apertured plate member 138 is retained by base plate 70 and
supports the chambered 134 cup member 136 which has a central
bore 142 that readily accepts the axial movement of the lower
part 144 of the rod 50 assembly that terminates with connector
52 and clamp-connector 140, the latter adapted to become fixed
to the element extending outwardly from vacuum interrupter 46
for actuation of the contacts therein. The upper flattened end
51 of rod 50 extends through aperture 126 in block 128 into
the narrow neck 146 of yoke 148 until aperture 150 is aligned
with apertures 61. An apertured yoke 62 is caused to overly
the assembly and pin 60 finishes the assembly (see FIG. 18).
Thus, the spring F can be pre-loaded between cups 128 and 132
and will exert a constant downward force, through the rod and
~~9~~~~
connector assembly, to the contacts of the vacuum interrupter
46.
Disposed on opposite outboard sides of the walls 72, 74,
are a pair of primary storable motive power tension springs
160. Spring 160 exerts a force through link 162 and pin 164 to
rotate lever 166 clockwise about pivot A-A. This rotation is
prevented by the latched position of '~D~~-shaped latch C
supported within toggle latch assembly 120 (see FIGS. 11, ilA
& 11B) which is also latched in the up position by plunger
toggle lever assembly 170. Levers 166 are connected to toggle
latch assembly 120 through pin 172, links 174, pin 176, levers
178, latch assembly 180 with its contact plate 182, and pin
184. Toggle latch assembly 120 is prevented from rotating
clockwise about pivot pin 184 by the interference of the latch
face 182 with the latch C at the surface designated D in FIG.
10. The yoke-like link assembly 148 is being forced to a
clockwise rotation about pivot pin 188 by the downward force
exerted by spring F through pin 60 telescoped within apertures
61 and 150 of the rod and connector assembly described above.
Pin 190, links 192 and 194 are connected to drive lever
assembly 196 to establish the position of pin E. Levers 198
are positioned in relation to levers 166 via pin 200 and
components pin 202, adjustment rod 204, spring G, shaft 200
and adjustment screw 112.
Referring now to FIG. 10A, note that the mechanism
linkage is shown in the open position. This position occurred
due to the clockwise rotation of latch C clearing the portion
D of latch face 182 allowing the clockwise rotation of toggle
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latch assembly 120 by the force exerted by spring 160 through
pin 176, link 174, pin 172, levers 166, pin 164 and links 162.
The clockwise rotation of levers 166 about pivot A-A in
contact with pin E by the contact surface H of lever 166 has
positioned pin E to the top of the slot J of walls 72 and 74.
Drive lever assembly 196 has been rotated clockwise about
pivot A-A via pin E that it supports. Links 194 and 192
attached to drive lever assembly 196 by pins K and 208 has
driven levers 148 to an upward position through pin 190. The
up position of levers 148 connected to rod 50 and connector 52
and pin 60 has moved the contacts of vacuum interrupter 46 to
an open position and simultaneously loaded spring F.
The contact opening stroke is accomplished in two
incremental phases of rotation by drive lever assembly 196.
The first segment of rotation by drive lever assembly 196 has
only links 192 in contact with pin 190 to drive levers 148
upward beyond the contact separation of the vacuum interrupter
46. The position of links 192 and pin 208 are so positioned
inward to pivot A-A on drive lever 196 to exert a high,
consistent predetermined force to break any welds that may
have occurred at the vacuum interrupter contacts. The final
segment of rotation by drive lever assembly 196 has only links
194 in contact with pin 190 to complete the opening stroke of
the interrupter contacts to a specific gap. The rotation of
pin K has been driven to a position, dictated by pin E in slot
J, beyond a straight line of pin 190 and pivot A-A. Coupled
with the constant downward pressure exerted by spring F
through levers 148 to links 194 and the smooth transition of
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pin K through the inline position of pin 190 and pivot A-A the
contact overtravel is minimized. The over-center and locked
position of pin K and links 194 prevent vacuum interrupter
contact rebound to close. The above description completes the
opening sequence of the vacuum interrupter contacts as guided
by the operating mechanism 20 of the present invention.
Referring now to FIG. 10B, the operating mechanism is
shown open, except toggle latch assembly 120 has been rotated
to the down position. This movement was initiated by a control
close signal to energize the electromagnetic release device 92
and forcing the plunger toggle lever assembly 170 to rotate
clockwise about pivot L and out of the over center, locked
position.
It should be interjected at this time that this mechanism
contemplates a manual form of completing a close operation in
the absence of high voltage for solenoid 38. There is a
closing shaft assembly having spaced elements fixedly mounted
on shaft M and including at one end a heavy lever 229 provided
with radially spaced bores 230 and 232, with bore 230 fixed to
shaft M; a pair of small spaced apertured levers 234; and a
pair of heavy apertured lever arms 236; with the aperture 237
carrying pin 210 for moving toggle latch plate assembly 120.
The manual aspect is provided by an accessory handle (not
shown) secured in bore 232 by means of pin 238. Thus, the
interrupter can be activated to close manually as well as
electrically/electronically. A manual operating handle 240 is
mechanically linked to parallel operation of close and trip
solenoids 90 and 92.
13
~0~~027
Plunger toggle lever assembly 170, as best seen in FIGS.
15 & 15A, includes a pair of spaced levers 220 that are
apertured at their free ends to accept pin 58 while at their
opposite or central end they are provided with an oval hole
221. A pair of heavier guage levers 224 are spaced outboard of
levers 220 and are joined thereto by pin 222, while at their
free ends levers 224 carry a fixed pin L which it in turn
carries a torsion spring P, the free ends of spring P being
adapted to contact fixed spring anchor 226 and fixed pin 228.
A downward pressure by a spring about shaft M and the
plunger weight on the plunger rod assembly 42 by pin 58 forces
toggles latch assembly 120 to rotate clockwise to the lower
limit of pin 210 in slot N. This clockwise rotation has
rotated latch assembly 180 counterclockwise into a reset
position with latch C with overtravel to insure positive
engagement. The clockwise rotation of the toggle latch 120
drives pivot pin 104 down beyond the over center position of
lever 100 allowing spring 122 to force lever 100 to rotate
counter clockwise moving the contactor link 56 to the up stop
position where pin 212 adjoins the lower surface of plate 70.
The upward movement of the closing solenoid contactor link 56
allows the energization of the pot coil assembly 38. This coil
energization will begin the closing function. Plunger 40 and
rod 42 assembly are forced upward by the electromagnetic force
of the pot coil 38 and being attached to toggle latch assembly
120 by pin 58, rotate said assembly 120 counterclockwise to
the latched position of plunger toggle lever assembly 170 (as
seen in FIG. 10) At this latched position the closing solenoid
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contactor 44 has been driven open to de-energize the pot coil
assembly 38 by the associated linkage of 100, 108, 110, 102,
112A, 106, 122 and 104 being returned to the position shown in
FIG. 10. The counterclockwise rotation of latch assembly 120
has also urged levers 166 through components 180, 184, 178,
174, 176, and 172 to rotate counterclockwise and extend
springs 160 to a fully charged state. Referring back to FIG.
10B, levers 198 through attachment to levers 166 via pin 200
also rotate counterclockwise moving pin 202 into contact with
detent surface P forcing drive lever assembly 196 and links
194 out of the locked position allowing the downward pressure
exerted by spring F to collapse the multi-linked system of
links 194, 192, and drive lever 196 to the down position shown
in section 10-10, i.e. see FIG. 10. Components 202, 204, 200,
112, and spring G provide adjustment to obtain the mechanical
sequence of remaking the plunger toggle lever assembly 170 to
its overcenter position, followed by closing of the vacuum
interrupter contacts.
Referring to FIG. 10 as well as FIGS. 16, 16A, spring F
is exerting a force to the piston 132 and has moved the
contacts of the vacuum interrupter 46 to a closed position.
Naving a spring F loaded to a predetermined pressure, the
force applied at contact make is instantaneous without delay.
This time is critical in minimizing contact rebound, blow
open, and contact welding upon initial contact make especially
at high fault current levels. The contact closing velocity has
been modified to reduce the impact energy at the interrupter
contacts via piston 132 and piston chamber 134, utilizing
~0~~0~7
transformer oil to provide hydraulic dampening. The piston is
directly attached to the contact rod 50 and the piston chamber
is attached to the base plate 70 by means of retaining plate
138 (see FIGS. 3, 16, & 16A).
Thus, structure and function have been provided to
support the allegation that this invention solves the seven
problems originally proffered.
16
