Note: Descriptions are shown in the official language in which they were submitted.
CROSS-REFERENCES TO RELATED APPLICATIONS
A related Canadian patent application by A. W. Hodgson
Serial No. 229,201 filed June 12, 1975 and assigned to the
- assignee of the instant application~ discloses an improved
operating mechanism for the circuit-interrupter assemblage of
the instant patent application.
BACKGROUND OF THE INVENTION.
Vacuum-type circuit-interrupters have been
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366~3
extensively utilized in industrial switchgear for con-
trolling feeder circuits, and for controlling, for example,
electrical motors of various ratings. In the case where
the air-brake interrupter units control electrical motors,
reference may be made to the following patents for back-
ground information: U.S. Patent 3,602r680, issued August
~1, 1971 to Alfred W. Hodgson; U.S. Patent ~,6~9.87~,
issued February 1, 1972 to Alfred W. Hodgson; U,S. Patent
3,621,3~9, issued Novem~er 16, 1971, to Alfred W. Hodgson;
U.S. Patent ~,264,431, issued August 2, 1966 to A, W.
Hodgson; U,S. Patent ~,264,432, issued August 2, 1966
to A. W. Hodgson et al; U,S. Patent ~,264.43~ issued
August 2, 1966 to R. D. Clark, Jr. et al, and U.S,
Patent 3,290,468 issued December 6, 1966 to R. D. Clark
Jr. et al.
When vacuum-type circuit-interrupter units
are utilized in place of air-break interrupting units,
invariably a metallic sylphon*~ellows is utilized to
hermetically maintain the evacuated condition withln
20 the vacuum-type circuit-interrupter envelope. It ~s
desirable not to impose any torsional, or rotational
stress upon this sylphon~bellows, which is manufactured
;~ for strictly linear straight-line motion. Also, the
operational life of such a vacuum-type circuit-inter-
rupter unit may approach one million operations, for
; example, so that it is necessary to prevent the lmposi-
tion of torsional, or rotational stress upon the metallic
bellows associated with the movable-contact stem of the
vacuum circuit-interrupter unit. Also, as will be well
~0 known by those skilled in the art, in the manufaeture
* trademark -~- ;
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1~3664~3
of vacuum circuit-interrupters, or vacuum "bottles", man-
ufacturing tolerances are somewhat wide, and vary over a
considerable range o~ dimensional values. It is, there-
fore, desirable to accommodate these widely different
manufacturing tolerances, particularly in the case where
a number of vacuum "bottles" are utilized in multi-pole
circuit-interrupting, or contactor apparatus, so that a
single operating mechanism may be employed, with facility,
to actuate a number of individual pole-units without im- : ;
posing any torsional stress upon an individual vacuum
unit other than a longitudinal linear motion, and also
. .
to accommodate considerable variance in the tolerances
of the individual vacuum "bottles'~ themselves.
SUMMARY OF THE I~VENTION
In the improved actuating means for actuating ~:
; the movable-contact stem of the movable contact o~ a
vacuum-type circuit-interrupter, according to the present
invention, a loosely-fitting movable-stem operator is
provided, being associated with a suitable affixment
means, such as a shoulder-bolt, for example, As a re-
sult, the rotatable contact-actuating levers may be
. placed into the proper operatlng position, with the
contact-operator loosely fitting upon the contact stem,
and, consequently, not imposing any torsional stres3
upon ~he stem, or ultimately upon the metallic sylphon (a
trademark) bellows of the vacuum circuit-interrupter unit,
Only as a ~inal operation is a clamping bolt
tightened, to thereby fixably secure the movable-contact
operator upon the lower external end of the contact stem~
- 30 clamping the two members ~ixed y together to thereby
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~03664
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subsequently actuate the movable-contact stem, and, con- -
sequently, the movable contact of the vacuum circuit-
interrupter, thus causing direct actuation between the
operator and the movable-contact stem, as initiated by
the ~ovable-contact-operating lever.
To accommodate variant manufacturing tolerances,
.
say, for example, the length of the vacuum interrupter
units, an accurately-machined lower support-flange plate
is provided, the latter having accurately-located pivot
apertures for the pivot pin to support, in a pivotal
. ~ .
manner, the contact-actuating lever. As well known by
those skilled in the art, the contact-actuating lever is
` mechanically linked to a suitable operating mechanism,
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of motor-starter -
" . . ... , : -.
equipment including two motor starters disposed in super- -
`- imposed relati~n together with their disconnecting-switch
'. structures;
Fig. 2 is a side-elevational view of the right
side of the truck-mounted contactor, or interrupter assem-
bly of the lnstant invention; `-~
Fig, ~ iB a front elevational view looking at
the front of the truck-mounted vacuum-type circuit-inter-
rupter asæembly of the present invention;
Flg. 4 is a vertical sectional view taken sub-
stantially along the llne IV-IV of Fig. ~ ~ th the sep-
~ arable-contact structure closed;
; Fig. 5 is an enlarged detailed view of the oper-
ating linkage and mechanism structure of Fig. 4, again
the separable contacts of the vacuum-type circuit-interrupter
':
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assembly being illustrated in the closed-circuit position
with the operating magnet energized;
Fig. 6 is a fragmentary vertical section view
taken substantially along line VI-VI of Fig. 3, again the
contact structure being shown in the opened-circuit posi-
tion;
Fig. 7 is an exploded perspective view of the . `r
several parts employed in conjunction with the improved
. ~
` operating mechanism of the instant invention;
~; 10 Fig. 8 illustrates, in side elevation, the
accurately-machined lower interrupter support-plate util-
ized in the present invention;
Fig. 9 is a front-elevational ~iew of the improved
accurately-machined interrupter support of Fig. 8;
Fig. 10 is an inverted plan view of the accurately-
machined interrupter support structure of Fig. 8; -
Fig. 11 illustrates a sectional view t~ken through
the improved shoulder-bolt and movable-contact operator con-
nection for actuating the movable-contact stem of the
vacuum-type circuit-interrupter of the present invention;
Fig. 12 is an enlarged side-elevational view of
the improved movable-contact operator utilized;
Fig. 13 is a top-plan vlew of the improved
` movable-contact operator of Fig. 12;
Fig. 14 is a front-elevational view of the im-
proved movable-contact operator of Fig. 12;
;~ Fig. 15 is an inverse plan view of the improved movable-contact operator of Fig. 12; and
Fig. 16 is a fragmentary vertical sectional view
taken along the lines XVI-XVI of Fig. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention has particular applicability
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to high-voltage motor starters 1 designed for starting and
controlling alternating-current motors. Generally, these
starters 1 are supplied in a steel floor-mounted enclosure
2, such as set ~orth in Fig. 1. me steel floor-mounted
enclosure 2 may, for example, accommodate two motor starters
1, as actually shown in Fig. 1 disposed in superimposed
relation.
e contactor assembly 7 comprises electrically -
isolated contactor poles 39, 41 and 4~ which represents
commercially-available componentsJ such as the Westinghouse
Electric Corporation contactor Type ~F-50V4~0 contactor,
Contactor electricaI terminal 45, as illustrated in Fig. 4,
engages an electrical terminal assembly to sup~ly voltage
through calbes to a remote load, which may be a motor
,
i installation.
me isolation switch assembly ~ is slidably
positioned within the cabinet housing 2 by outwardly-
; protruding flanges which engage horizontal guide tracks.
Due to the w~ight of the contactor assembly, 7
it i8 generally located in the bottom section o~ the
.
cabinet housing 2, The positioning of the contactor
assembly 7 within the cabinet housing 2 is accompliRhed -~
by inserting the wheels 49, which are affixed at the
four corners of the base 51 of the assembly 7, into
guide tracks and rolling the assembly 7 into the cabinet
housing 2 until electrical engagement with the electrical
: ,
; terminal assembly occurs.
The ~acuum-type contactor 7 is designed for
- starting and controlling three phase, 50-60 cycle alter-
nating-current motors. The voltage may, for example,
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~ 103664~3 j
be 6,600 and the contactor-closed continuous rating in
; amperes 360.
- Fig. 2 illustrates, in side elevation, the right-
hand side 55 o~ the truck-mounted vacuum-type contactor
assembly 7. As illustrated in Fig. 2, it will be observed
. . .
that there is provided a direct-current operating magnet
57 having a direct-current magnet coil, or operating coil
; 59. Associated with the ~agnet structure 57 is a rotatable
magnet armature 61 whlch makes abutting engagement when the
operating magnet 57 is energized with the magnetic pole-
race 63. me lower end 61a of the rotatable magnet arma-
ture 61 ls a~ixed by a clamp casting 65 and a key 67 to
the external end o~ an operating shaft 69, as shown. Also
a~fixed to the operating sha~t 69 is an electrlcal inter-
lock pushrod 71 which operates an electrical interlock 73.
- In addition, Fig. 2 shows a protective resistor 74 wh~ch is
; inserted into the series magnet coil circuit 57 when the
armature 61 has reached lts fully-closed position against
the pole face 63, as illustrated by the full lines in Fig.
2. Additionally, there i8 illustrated in Fig. 2 another
.
interlock 77. Also Fig, 2 illustrates an isolating-switch
; mechanical interloc~ arm 78, which i8 operable by a down-
wardly-extending interlock rod (not shown) extending down-
wardly and operable by the lsolating-switch as~embly 3.
Flg. 3 shows that, in general, the truck-mounted
~ contactor assembly 7 comprises two side metallic support
; plates 80 and 81 interconnected by a rront U-shaped met-
allic support channel member 83, which is more clearly
illustrated ill Fig. 3 of the drawings. Also Fig, 4 shows
the lower stab assembly 45 which interconnects the co~tactor
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103664t3
- assembly 7 with stationary load te~minals for operating an
external piece of equipment, such as an electrical motor,
for example. ~ ~
Fig. 3 illustrates a view looking into the front --
of the truck-mounted vacuum-type circuit-interrupter assem-
- bly, or contactor assembly 7. It will be observed that ~
the armature 61 of the operating magnet 57 is affixed to ~ ;
the external end of the operating shaft 69 and effects the
rotatable operating motion thereof. The operating shaft
69 is, of course, journaled in suitable bearings 99, 101
provided on the inner sides ~Oa, ~la of the two metallic
i side support plates ~0 and ~
It is, of course, desirable to provide contact-
closing spring pressure for each of the individual pole-
units 39, 41 and 43 in the closed circuit position of the
contactor assembly 7, as illustrated in Fig. 4 of the
drawings. Each pole-unit 39, 41 or 43 is provided with
its own individual vacuum-interrupter unit 103 and a
pivotally-mounted rotatable contact-operating arm 105,
which is pivoted upon a stationary pivot pin 107 extend-
ing between the two downwardly-extending flange portions
10~, 109 of a U-shaped lower interrupter support 110,
the configuration of which is more readily apparent from
a study of Figs~ 4 and 5 of the drawings.
The rotation of the rotatable contact arm 105
is effected by a laterally-extending cross-bar 112 which
is moved in generally a vertical direction by two spaced
crank-arms 114, 116 the latter being affixed to and
rotatable with the operating shaft 69. Fig. 3, taken
in conjunction with Fig. 4, more clearly shows the
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structure of the laterally-extending cross-bar 112. As
illustrated in Fig. 4, it will be observed that the cross-
bar 112 is preferably of metal, and in this particular
instance has a square cross-section, as shown, having end
pivot-plns 118, the latter being apparent from a study of
Fig. 3 of the drawings,
The cross-bar 112 is fixedly secured to an insu-
~; lator support 120 individual to each of the three pole-
units, 39, 41 and 43 as more clearly illustrated in Fig.
3. The insulator s~pport 120, in turn, supports an abut-
ment member or in this particular instance a plate 122, -
for example, having a configuration more clearly apparent
from a study of Fig. 7 of the drawings. Fig. 7 lllustrates
an exploded view of the contact-pressure spring assembly
124 and the relatlonship between the abutment member or
plate 122 and a rotatable reverse-current loop-arm assem-
bly 126, again the configuration of which is more clearly
-, apparent ~rom a study of Fig. 5 of the drawings.
AB well known by those skilled ln the art, it iB
desirable to supply contact-spring pressure between the
separable contacts in the closed-circuit p~sitlon of the
interrupter 103. This spring pressure, which is provlded
in the instant invention, is afforded by a compression
spring 128 illustrated in Figs. 3 and 5, and interposed
between the abutment plate 122 and an upper movable spring
seat 130, which straddles the two contact-actuating arms
;.
105a, 105b, which collectively constitute the movable
contact-actuating arm 105 o~ the interrupter assembly 7.
It will be observed, in connection with Figs.
4, 5 and 7 of the drawings, that a contact drive pln 132
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~366~'~
passes through the two leg portions 105a, 105b of the
movable contact-actuating arm 105 and, additionally, passes
through a pair of apertures 134 provided in the rotàtable
- reverse-current actuating arm 136. In other words, the
same pivot pin 1~2 passes through the two leg portions
105a, 105b of the contact-actuating arm 105 and also
through the leg portions 136a, 136b constituting the ~--
reverse-current arm-assembly 136, thereby enabling a
fulcrum point to be exerted at the pivot pin 107
in the contact-welded condition of the separable contacts
138, 1~9 under certain conditions, as more fully described
hereina~ter,
With reference to Figs. 4, 5 an~ 6 of the drawings,
it will be observed that there is provided an overtravel
ad~usting nut 140~ which is threaded upon the upper end
142a of the contact-pressure stud 142, the lower end of
which is secured into the upper end of the insulator
.
support 120. mus, in the closed-circuit position of the
vacuum-interrupter assembly 7, as illustrated in Fig. 4,
the contact compression sprlng 128 i8 compre~sed, thereby
applying contact-closing pressure between the separable
contacts 138 and 139, the overtravel ad~usting nut 140
aecommodating the "wipe" travel distance by continued
closing travel of the contact-actuating arm 114. mus9
Fig. 4 illustrates the closed-circuit position of the
interrupter device 7 with the operating magnet 57 ener-
gized and the compression spring 128 providing the de-
sired contact pressure in the closed-circuit position
of the device.
- 30 It will be obvious that during the opening
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1~3664~3
operation, the operating shaft 69 will rotate in a counter-
clockwise direction, as viewed in Fig. 4, carrying down- -
wardly with it the two operating arms 114 and 116 together
with the cross-bar 112 and the three insulator 6upports
120. Also carried downwardly will be the abutment plates
122 and the contact pressure studæ 142 until the overtravel
ad~usting nuts 140 engage the yoke portions 130 of the
contact actuating arms 105, as illustrated in Fig. 6 o~
the drawings. Assuming that there does not exist a welded
condition at the separable contacts 1~8, 139, the operating
mechanism 144 will continue its counterclockwise opening
movement carrying the separable contacts 1~8, 139 to their
fully-open circuit position, as illustrated in Fig. 6 of
the drawlngs.
~ The interrupter unit 103 may be of any suitable
; type manu~actured commercially by a number o~ companies,
and, in general, comprises an evacuated envelope 145
having end metallic plates 146, 147 hermetically sealed
to the ends of the insulating envelope 145, such as a
ceramic sleeve, ~or example, The vacuum "bottle" 103 is
provided havlng supporting stud portlons 149, say three
; in numberJ ~or example, extending upwardly and downwardly
; as illustrated in Figs, 5 and 6, and also having the
movable contact stem 150 extending externally, as illus-
; trated in Figs. 6 and 7, In its manufactured component
; assembly form, it isJ there~ore, provlded in a form
. .
enabling its ready mounting by the six mounting studs
;` 149 and the movable contact 139 may be opened and closed
- by an actuating cla~ping portion 152 secured to the ex-
tending end 150a of the movable co~tact stem 150. The
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11~3664!!3
present equipment utilizes preferably, one of these manu-
factured "bottles" 103 for each pole-unit 39, 41, 43. As
illustrated in Fig. 5, there is provided an upper inter- -
rupter support casting 154, cast, in this particular in-
stance, of aluminum, which has a horizontally-extending
apertured support-flange portion 154a having mounting
holes 154b therein to accommodate the three upwardly-
extending mounting studs 149, the latter, as mentioned,
constituting a part of the man~factured bottle 103.
Mounting nuts, not shown, threadedly secure the æupport-
flange portion 154a of the casting 154 ta the vacuum
, . : :
i "bottle" 103 and maintain it fixedly in a proper position,
me casting 154, in addition, has a pair of downwardly-
slanting support arms 154c, which are interconnected by
a second supporting flange portion, or yoke portion 154d,
~; the latter being affixed to an upper insulator æupport
158 (Fig. 5) and to a metallic conduc~or support strap
160, the latter being securely mounted to an upper fuse-
.
finger terminal assembly, generally designated by the
reference numeral 162, and illustrated more clearly in
Fig. 4 of the drawings. A fuse-finger contact-pressure
.~ ..
- spring 166 is utilized, as illustrated in Fig. 4, sup-
I ported between the pivotal fuse-finger portlon 168 of
~. ~,; .
the terminal assembly 162 and a spring seat 170 asso-
ciated with a mountlng bolt 172, the latter extending
through a vertically-disposed insulating spacer block 174,
;1 the latter being secured by mounting bolts 172, 176 to
.. ..
` a laterally-exte~ding insulating support plate 178 of
: the frame 180. In addition, a metallic angle 181 ls
'- i
:~ 30 provided to rigidly interconnect the horizontally-
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1(~3664~3
extending line-connection strap 160 with the hori~ontally-
extending conductor strap 182, Fig, 4 again showlng this
construction more clearly. A mounting bolt, not shown, extends
vertically through the several component parts, as also
shown in Fig. 4.
Fixedly secured to the upper extremity o~ a line-
connection strap 160 is a terminal clamp 186 having a
clamping portion 186a which encircles the upper eætending
end 188 of the stationary contact stem 189, as more clearly
shown in Fig, 6. Due to the inherent flexibility provided
by the line-connection strap 160 (Fig. 4), there is not
exerted any stress nor torqueing action upon the stationary
contact stem 188. However, with reference to ~ig. 4J it
will be observed that the bottle structure 103 itself is
rigidly supported by the rclatively massive and heavy upper
` , interru~ting casting support 154.
~ To counteract the inward closing force exerted
- because of the evacuated environment 190 within the evac-
uated enclosure 145, a kickout spring 192 ls provided to
compensate for the atmospheric pressure, the latter, of
course, tending to force the separable contacts 138, 139
into the closed-circult position, as illustrated in Fig. 5.
. ~ ., .
The kickout spring 192 is interposed between a lower
metallic washer 193 and the upper end of contact operator
152,
- With reference to Figs. 4J 5 and 6 of the drawings,
` it will be observed that there is provided at ~he lower
. end of the contactor-assembly 7 a reverse-current connec-
tor-assembly 126 comprising a generally loop-shaped flex-
30 ible connector 195 having an upper terminal 196 fixedly
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~ 36648
secured by a connector bolt 197 to the lower end of the
movable contact operator 152. me flexible connector 195
extends rightwardly, as viewed in Flg. 5, into a loop
portion "L", and then extends toward the le~t, as viewed
in Fig. 5, to be secured by a connector bolt 199 to the --~
mid-portion 200 of a stationary U-shaped current-feeding
member, generally designated by the reference numeral 201
and having a configuration more readily apparent from a
ætudy of Fig. 6 of the drawings.
Aæ indicated in Fig. 6 of the drawings, the
current-feed structure 201 comprises a pair of statiDnary
L-shaped leg members 210, 211 bolted, as at 212, to the
side walls 214, 215 of the lower interrupter casting
support 216, and having a bight portion at the front
thereof, designated by the reference numeral 200, me
-~ bight portion 200 is electrically eonneeted to the lower
'~ terminal 198 of the loop-shaped reverse-current loop
assembly 126, as indicated more clearly in Fig, 5, which
has the desirable advantage, namely an augmentation of
the upper movable flexible strap portion 221 by the mag-
netic fleld around the leg portions 210, 211 of the L-
shaped reverse-current feed structure 126.
To obtain the higher meehanlcal ~orces only
` during an occasional system fault, without increasing
the mechanlcal forces in effect in normal operation, the
; novel reverse current loop is provided as shown in Fig. 5.
mis reverse-current loop 126 provides an in-
crease ln contact force and also weld-breaking force
which is in proportion to the square of the current "I"
flowing through the reverse current loop.
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~03664~3
~ y properly proportioning the reverse-current
loop 126, it is possible to provide a substantial increase
in the contact and weld breaking forces under high-current
conditions wh~le only slightly increasing these forces
under normal operating conditions.
The reverse-current loop 126 consists o~ upper
and lower shunt legs, not shown, plus parallel load connection
bus bars 210, 211 as shown in ~igs. 4 and 5.
When current flows through the reverse current
loop conductors 221, 222, the magnetic fields surrounding
- these conductors 221, 222 react with each other to develop
mechanical forces on the various conductors,
The lower horizontal leg 222 of the shunt and the
parallel load connection bus bars 210, 211 are restrained
by non-movable parts of the support structure 180, while
the upper shunt leg 221 is free to move upward until it
strikes the right-hand end of the reverse-current loop-
~ arm 136.
: ~ When the contactor 7 is sub~ected to a power
i 20 system fault, of high current magnitude, the reverse cur-
" rent loop 126 will apply a force upward on the right-hand
end of the reverse-current loop-arm 136 which will in
:
.r . turn pry the interrupter contacts 138, 139 closed assum-
ing the contactor magnet 57 remains closed.
A second reaction of the reverse-current loop-
. ,.
arm 136 i8 to apply a downward force on the contact spring
:~: support plate 122 which will in turn increase the opening . .: .
velocity of the magnet and cross-b~r assembly 112 once
the magnet 57 is de-energized~
. 30 When the magnet 57 is released, the moving ~:
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1~36648
assembly is accelerated by the combined ~orces o~ the con~
tact springs 128 and reverse current loop 126 until there
is no gap at the contact overtravel ad~usting nut as shown
in Fig. 6.
;At this point, the kinetic energy of the mo~ing
system imparts a hammer blow to the contact actuating arm
105 which acts to break any contact welds which might
exist.
When the overtravel adjusting nut 140 makes con-
10 tact with the upper contact spring seat 130, as shown ln -;
Figure 6, the function o~ the reverse current loop 126
automatically takes a complete re~ersal to apply an addi-
tional contact opening force to the interrupter 7 rather
than a contact closing, as it previously had done when the
magnet 57 uas closed.
In this design the connection from the contactor
.,
~,load terminal 45 to the lower leg 222 of the shunt 195 is
divided into two parallel legs 210, 211 which straddle and
.:.
are mounted at the same elevation as the upper leg 221 of
the shunt.
A kickout spring 192 is mounted dlrectly on the
contact shaft 150 of the interrupter 103 to take up the
play between the contact actuating mechanism 144 and the
interrupter contacts 138, l3g~ Without a kickout spring
192 ln this location, the contacts 138, 139 could touch
momentarily under low contact force conditions while play
is being taken up in the operatlng mechanism 144. Play
between the contacts and operating mechanism 144 would
aggravate the contact erosion and welding problems both
on the opening and closing operations.
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~3~64~
The kickout springs 192 also minimize armature
bounce on opening and in addition are proportional to apply
sufficient load on the magnet 57 at open gap position to
prevent the magnet 57 ~rom picking up unless its operating
voltage iB sufficient ~or the magnet 57 to seal-in from
. the contact-touch position.
: Each pole 39, 41 and 4~ o~ the contactor may be
.. ~
installed or removed from the contactor as an individual
sub-assembly, so that it may be efficiently assembled or
mai~tained at a work-bench rather than in the contactor 7.
The interrupter unit itself may also be i~stalled
: or removed from the contactor as a smaller sub-assembly
- consisting of the interrupter 1O~J its support 154, moving
. contact actuating arm 105, and reverse current loop de- .~ .
, . .
tails 126 as shown in the exploded view of Flg. 7. :
' In order to obtain maximum mechanical life of
the interrupter bellows 235 and al80 avoid ~riction between
. the interrupter contact shaft 150 and its bushing, it is
... . .
~. important that the relationship between the contact drive
. . .
:. 20 ,pln 132 and the pivot pln 107 ~or the contact actuatlng
arm 105 be accurately maintained~
.
To accomplish this, the interrupter 103 and the
contact actuating arm 105 are both mounted on a single
. ~ ' .
~.- rigid mechanical detail 110 which can be accurately manu~
.` factured. m ls detail 110 is the lower interrupter :.
mounting bracket shown in Fig. 7,
; In connection with the above alignment of parts,
: it is also deæirable that the contacts 138, 139 touch
when the contact drive pin 1~2 is on the sa~e horizonta
: 30 centerline, not shown, as the pivot pin 107 for the C01
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- - , . . : .
1~36~4~
actuating arm 105.
: When the interrupter sub-assembly is being
assembled, the kickout spring 192 is placed over the con-
tact shaft 150 and then compressed by the contact operator
152 which in turn is held in place by the shoulder bolt
239, me shoulder b~olt 239 is only tightened finger tight
so as not to apply excessive torque to the interrupter
; shaft 150 and bellows 235.
The contact operator 152 and shoulder bolt 23g
de~ign is coordinated in a manner that the shoulder bolt
239 cannot elamp the contact operator 152 to the contact
shaft 150, but instead permits the contact operator 152
:; to rotate freely on the contact shaft 150 without appl~ing
. torque to the contact shaft 150 when the contact operator .
! ~ 152 is being lined up with the contact-actuating arm 105.
~: After the contact drive pln 132 is installed,
,~r the contact actuating arm 105 is depressed to take up the
.: play between the contact drive pin 132 and contact shaft
'r. 150 following which the contact operator 152 is clamped
'~ 20 to the contact shaft 150 by tlghtening the clamping bolt
:
241,
.~ In normal service, the contaet shaft 150 will be
açtuated through the clamped ~oint between it and the
contact operator 152, but shou~ this ~oint fail the con-
tacts 138J 139 will then be closed by compression of the
; parts between the drive pin 132 and the end 150a of the
contact shaft 150, and opened by the shoulder bolt 239.
One of the ob~ects of the present invention is
to prevent excessive torque ~rom being applied to the
: 30 shaft 150 of the interrupter 103 during ma.lntenance
. . ~
~ ' ` ' - 19-
., .
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~Q36~48
and/or assembly since torque may destroy or shorten the
mecha~ical life of the interrupter bellows 235,
me shoulder bolt 239 acts as an assembly fix-
ture to compress the kickout spring 192 during assembly
while still allo~ing the contact operator 152 to be
rotated as required to install the con~act drive pin 132.
In operation the shoulder bolt 2~9 in addition acts as
a sa~ety device to insure opening of the contacts in the
event the contact operator 152 is not securely olamped ;~
10 to the interrupter contact shaft 150.
The inter~upter 10 ~ is rigidly supported at its
upper end, which contains the interrupter stationary con-
tact 138 so as to avoid transmitting contact forces through
the ~alls 145 of the interrupter 103. me moving contact ~-
end 150 of the interrupter 10~; in addition is clamped to
;; the stationa~ portion of the pole assembly to provide
lateral stability. Clamping of the lower end o~ the
interrupter sub-assemblg "SB" is accomplished by mea~s
., - .
of an oversized open slot 243 which compensates for the
20 manufacturing tolerances of the interrupter 107 and also
simplifies installetian and removal of the interrupter
sub-assembly "SB",
Manufacturing tolerances on the interrupter
length dimension "X" are rather large, so the vertical
locations of the lower ends o~ the interrupter 103 may
vary considerably from contactor 7 to contactor 7 and
from pole to pole. Since the operating mechanism 144
for each pole is mounted on the moving contact end "E"
of the individual interrupters 103, r~ther than on some
30 fixed portion of the pole assembly, this is of little
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consequence.
In the event the interrupter length "X" is found
to be other than its nominal value, the final lengths of
the contact springs 128 will also vary from their nominal
value resulting in either high or low contact forces.
me average contact ~orce in the case of a
- multiple-pole contactor, as sho~n in the drawings3 can7
however, be corrected by adjusting the angular position
of the magnet armature 61 on the operating shaft 69 so
10 that the correct average contact spring length and force
128 is obtained when the magnet 57 is sealed-in.
.. .
Angular position ad~ustment of the magnet arma-
ture 61 is a standard feature of an existing air-break
contactor magnet 57 applied to the disclosed vacuum con-
~-- tactor 7.
Variations in contact forces between poles
existing after the magnet ad~ustment 61 has been made
will fall within allowable limits if the contact springs
128 are designed to have a low spring rate.
NON-TORQUE ACTION EXER~ED 13Y SHOULDER-BOLT 2~9
To avoid imposing torque action upon the movable
contact stem 150 and thereby exerting corresponding torque
actic~n upon the bellows 235, the utilization of a novel
shoulder-bolt 2~ is provided. The construction of the
shoulder-bolt is set forth in Figs, 11-12 of the drawings.
It will be observed that the bore 245 of the contact-shaft
" operator 152 has a relatively loose fit on the contact
....
stem 150 as shown ln Fig. 11, the shank 239a of the
shoulder-bolt 239 has a loose fit at "C" with the movable
~0 contact operator 152. The shoulder-bolt 239, for example,
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1~3664~3
may have an Allen head with an enlarged portion 239a and
a reduced portion 239b with a shoulder 247 therebetween,
so that the shoulder-bolt, when tightened, will force
washers 249 (Fig. 11) against the lower extremity 150a ~ ~ -
of the moving-contact shaft 150 of the vacuum-type inter- ~ .
rupter 103. mis is shown in Fig. 11. The number of
washers 249 is arranged to accommodate the tolerances
provided between the different movable contact shafts
150 of the several pole-units 39, 41 and 43. Once the ~ ;
shoulder-bolt 2 59 is tightened, the contact-shaft opera-
tor 152 is moved manually upwardly, so that there is no
clearance at the point "D" in Fig. 11. Then the elamping ~:
.
bolt 241 of Fig. 7 is tightened, so that the movable con- :
- tact shaft 150 is operated by the contact-shaIt operator
. 152, the latter having the apertures 250 provided therein : . .
- to accommodate the center-line of the contact-drive pin
1~2. As a result, there is no torque action exerted either
upon the movable contact shaft 150, or the bellows 235
located interiorly of the vacuum envelope 103. ~here may,
20 of course, be relatively wide tolerances provided in the
vacuum-bottle manufactureJ and the foregoing arrangement
permits a desirable accommodation of these tolerances,
VACUUM-BOTTLE TOLERAl~CES
Despite the wide la~itude of the tolerances pro-
vided in the manufacture of the vacuum bottles 103, it is
desired not to impose any stress upon the ceramic envelope
145, or to effect the breakage o:f any of the he~netic
seals 251, To effect this end, an accurately-machined
- lower-interrupter support-plate 110 having the pivot
. 30 apertures 252 proYided therein is supplied. These pivot ~ .
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~36648
apertures 252 may be accurately machined, and once the
- vacuum bottle 10~ is fixedly secured by the upper
interrupter casting 154, as a first operation, subse-
quently, as a separate operation, the U-shaped
accurately-machined support plate 110 is secured into
place by the lower three mountlng bolts 149. me pivot-
: pin 1~2 may then be accurately located with respect to
the lower interrupter support 110 because of the
~ accurate machining of the pivot apertures 252 therein~
10 This will accurately locate the contact-
actuating lever 105 and, additionally, accurately locate
the contact-stem ~riving pin 132. As mentioned pre- :
viously, the contact-sha~t clamp bolt 241 is tightened
as a final operation after previous assemblage of the
contact-pivot pin 132 and tightening of the ~houlder bolt
239.
From the foregoing description, it will be :
apparent that there has been provided an improved movable ~ ;
: contact operator for the separable contacts of a circult-
:.
interrupter, particularly applicable to one of the vacuum-
: type.
Also, it will be o~served that with the
improved operation mechanism, and the reverse-current
loop system, the function o~ the reverse-current loop-
system changes in dependence upon whether or not the ..
operating magnet 57 i8 energized, or is not energized,
In the energiæed ~ate o~ the operating magnet 57, an
addltional force is provided to maintain the contacts
. 138, 139 closed during the existence of heavy-fault-
current conditions. When the magnet 57 is not energized,
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the fulcrum point changes, or is relocated to thereby
provide, insteàd of a closing force, in this instance
an opening force, which assists and augments the accel-
erating opening springs. .
Although there has been illustrated and
- described specific embodiments of the invention, it is
- to be clearly understood that the same were merely for
.. the purpose of illustration, and that changes and
~; modifications may readily be made therein, by those
skilled in the art, without departing from the spirit
and scope of the inventionO
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