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. 228,892, filed 7une 9, 1975 entitled "Improved
Movable Contact-Stem Operator For A Vacuum-Type Circuit-
Interrupter", and assigned to the assignee of the instant
: patent applicatlon, discloses ~nd claims the means for
adjustment of the movable contact-stem operator for the
movable contact of the circuit-interrupter disclosed herein.
;. BACKGROUND OF THE INVENTION
Circuit-interrupters particularly of the vacuum-
type are relatively new on the commer~ial market, and have
enjoyed only limited success due to several severe ~hort-
` comings. In an effort to minimize the most serious of these
shortcomings, the vacuum-interrupter manufactures have found
. --1-- ~
. '.
. : .. .. , : .
~(~36644
it necessary to use contact materials which are susceptible
to welding. me welding problem, however, can be minimized
by the use of contact and weld-breaking ~orces approximately
ten times those usually iound in a conventional air-break
contactor o~ comparable rating.
Vacuum-interrupters having the most desirable
~ interrupting characteristics and longest contact life have --
- been found to weld at currents considerably below their
interrupting limit, so that the interrupter rating o~ a con-
tactor using these vacuum-type circuit-interrupters is
limited by the ability of the actuating or operating
mechanism to overcome the welding problem, rather than by
.- :
the arc-interrupting ability o~ the vacuum-type circuit-
interrupter.
;'' '''' '~ ~ :''
'
,~ ' ~'.
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~ - , :, .
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10366~
A three-pole contactor having a magnet and frame
as embly proportloned to meet the design requlrements of the
vacuum-lnterrupter, and stlll have a reasonable mechanical
llfe would be much too large and costly to compete with
exlstlng alr break contactors whlch require only a fraction
of the contact force. As result of thls "squeeze", presently-
avallable vacuum-type contactors, are a design compromlse
whlch do not completely satlsfy the requirements of the vacuum-
lnterrupter, and as a result do not perform as well as exlst-
..;
~` 10 ing available alr-break contactors.
The very hlgh contact forces mentioned above are
requlred only when lt ls necessary to obtaln the maximum
.:
monentary current rating of the vacuum-lnterrupter, whlch is
ln the event of a power-system fault. Slnce the contactor
may ~eldom see thls current conditlon ln actual service, a
,i,j ., ~ , ~
s, contactor deslgned to contlnuously provlde these high contact- ~
.
; closlng forces would represent a rather lnefflclent use of
space and materlal.
A reasonable-slzed operatlng magnet, coupled to the
lnterrupter shaft through a toggle mechanlsm, or other system
of levers, could be devlsed to develop hlgh contact closing
forces, but the hlgh mechanlcal advantage of thls mechanlsm
would act to reduce the contact-operatlng speed far below the
- values recommended for the vacuum lnterrupter. The high
mechanlcal advantage of thls mechanlsm would, in addltlon,
result ln low or dlminished contact overtravel, whlch, ln
turn, would make frequent ad~ustment of contact overtravel
necessary.
-~ Reverse-current loops have been employed ln the
past to increase the contact-closing forces under heavy
~ 43,102
. '. ' .: ,'
3~i69~4
fault condltions, but have had the tendency to override the
operatlng magnet. A reverse-current loop of this type,
; deslgned to supply the requlred contact-closlng forces of a
three-pole vacuum contactor, would exert so much force that the
reverse-current loop would hold the contacts and magnet
- closed even after the magnet ls de-energlzed. A weak reverse-
current loop of this type would not hold the contacts closed,
but would act to reduce opening speed and weld-breaking
forces, which ls also undeslrable.
SUMMARY OF THE INVENTION
;~ In the improved vacuum-type clrcuit-interrupter
and mechanlsm of bhe present lnventlon, the contact closlng
~ sprlngs, operatlng magnet and other structure are pro-
- portloned to provide the proper contact closing forces
sufflclent to lnsure satlsfactory performance under motor
startlng, runnlng, and locked-rotor condltions for the
maxlmum sized motor with which the contactor wlll be used.
; The operatlng mechanlsm for the separable contacts of the
vacuum-type clrcult-lnterrupter ls such that a reverse-
current loop ls employed ln con~unction therewlth whlch has
two opposltely-directed functions. In the closed-circuit
position of the circult-lnterrupter, or contactor, with the
magnet energlzed, the fulcrum point of the reverse-current
actuating arm is so located that upon a sudden lncrease of
the current magnltude passlng through the circult-interrupter,
.,
or stated otherwise, under heavy-fault conditlons exlstlng ln ;~
the controlled clrcuit, the magnetlc forces ln ~he reverse-
. . .
current loop structure are directed to lncrease the contact-
: clo~ing forces, thereby asslstlng the contact-sprlng pressure
provlded by the operating mechanlsm ltself.
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However, when it ls desired, on the other hand, to
open the contacts of the vacuum-type clrcuit-lnterrupter, or
contactor, the de-energization of the operatlng magnet wlll be
reflected through the disclosed linkage structure to change
the location of the fulcrum point of the reverse-current
act~atlng arm to thereby bring about an opposlte function or
effect of the reverse-current loop structure, or ln other
words, ~o redirect the forces created by the verse-current
loop structure, so that at this tlme the magnetic forces,
generated by the reverse-current loop structure, actually
asslst the operatlng mechanism to open the separable contacts,
and to break any welded condition exlstlng at the contacts
themselves.
Thus, the lmproved reverse-current loop structure
. i .
of the present lnvention has two lmportant functions. The
;; flrst function is to lncrease the contact-closlng forces,
, thereby asslsting the contact-pressure sprlngs ln the closed-
clrcult position of the circuit-interrupter, when the magnet
structure is energized, under the conditlons Or high-fault
current passing through the interrupter. In thls case, con-
¢eivably a remote clrcuit-breaker would be desired to open
the circuit rather than the contactor and the magnet would
remain energlzed as desiredO Depending on whether the oper-
ating magnet of the contactor is energized or not, depends
- upon whether or not the fulcrum point of the reverse-current
actuating arm changes, and thereby affects the function and
operation of the reverse-current loop system.
Assuming, for instance, that lt ls desired to open
the circuit-interrupter, or contactor, the de-enèrgization Or
30 the operating magnet structure wlll effect automatically a -~
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-
~3~ ~;
relocation of the fulcrum point of the reverse-current
actuatlng arm and thereby drastically change the operatlng
function of the reverse-current loop system to thereby result
in an entirely oppositely-dlrected force, this time a force
directed to open the separable contacts and thus to break any ;-
welding condltlons existing thereat. `
In the lmproved operatlng mechanism of the instant ~-
invention there ls associated with the rotatable contact-
operating arm an abutment member, such as a plate, for example,
which ls associated with the contact-pressure spring, and a
reverse-current loop arm pivotally mounted to the contact-
actuating arm has a nose portion bearing on said abutment
member or plate, and operable during the de-energized conditlon
of the magnet to act in an opening directlor. against sald
abutment plate, and have lts fulcrum point at the pivot-shaft
location between the contact-actuating arm and the movable
contact stem. Thus, magnetic forces are brought lnto play to
redirect the reverse-current loop effect, and to pry, in effect,
.. .
the welded contacts apart, and thereby asslst the opening
accelerating springs of the circuit-interrupter or contactor.
In more detall, the reverse-current loop system of
the present lnvention comprises a metallic conductlng arm
carrying the line current to the interrupter contacts, and
, . ..
` pivotally mounted on the same plvot shaft location at which the
rotatable contact operating arm pivotally connects to the
movable contact stem of the vacuum-interrupter. By thus
~ belng pivoted to the movable contact stem with the rotatable
; contact-actuating arm during heavey-fault current condition,
the magnet repelling effect between the sldes of the loop ~-
forces the separable contacts more firmly closed under high-
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1~3664~
fault condltions, when the magnet ls energlzed, as ls desired.
On the other hand, durlng the opening operation,
when the operating magnet ls de-energized, and thy operating
mechanism is stalled at the contact-touch point, due to a
welded condition exlsting at the separable contacts; or in
other words, the contacts are, in fact, welded closed, the
reverse-current loop arm acts ln a manner to break the con-
tact weld by relocating the fulcrum point, of the reverse-
current actuatlng arm so thRt it now exists at the pivot
: 10 polnt for the rotatable contact aPm with the movable contact
stem.
Another very important feature of the present
invention is the structure for supplying or feeding series
current to the reverse-current loop arm, so that it does not
oppose or tend to neutralize the magnetic action of the
reverse-current loop arm. This is achieved by a speclal
~. stationary current-feed clrcuit, which locates the current-
feeding arms in roughly the same plane as the movable portion
o~ the reverse-current loop arm, so that, the fact, the
`~ 20 magnetic effect, generated at the two sationary current-
feed arms, is to increase and augment the magnetic effect
. .
exerted on the movable portion of the reverse-current loop-
. ~ , ,.
- arm structure.
BRIEF DESCRIPTION OF THE DRAWINGS ~ ~ :
Fig. 1 is a perspective vlew of motor-starter equip-
~ ment including two motor starters disposed in superimposed
~ relation together with their disconnectlng-swltch structures;
, .
Fig. 2 is an enlarged vlew looklng lnto the interior
of a cell-structure adaptable for accommodatlng the improved ~ ;
30 roll-in vacuum-type circuit-interrupter structure of the : ,
.:
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.
lQ36644 ~
instant inventlon, wlth the access doors for the low and
hlgh-voltage compartments being open;
Flg. 3 is a side-elevational vlew of the right slde
of the truck-mounted contactor, or interrupter assembly of the
- lnstant invention;
Fig. 4 i3 a s~de-elevational vlew of the lefthand
slde of the truck-mounted vacuum-interrupter assembly of the
present invention;
Fig. 5 is a front elevational v~ew looklng at the ;~
, lO front of the truck-mounted vacuum-type circuit-lnterrupter
; assembly of the present lnventlon;
Fig. 6 is a vertical sectional vlew taken sub-
stantially along the line VI-VI of Fig. 5 with the separable-
contact structure closed;
Fig. 7 ls an enlarged detalled vlew of the oper-
atlng llnkage and mechanism structure of Fig. 6, again the ~ ~-
separable contacts of the vacuum-type circuit-interrupter
assembly belng lllustrated in the closed-circult positlon with
the operatlng magnet energized;
Fig. 8 ls a fragmentary vertlcal sectlon view taken
substantlally along line VIII-VIII of Fig. 7, again the con-
tact structure belng shown in the closed-clrcult positlon;
Flg. 9 ls a vlew slmllar to that of Fig. 7, but
lllustrating the separable contacts of the vacuum-lnterrupter
`~ unlt ln the fully-open ciruit position with the operatlng
magnet de-energlzed;
Flg. lO is an exploded perspectlve vlew of the
several parts employed ln con~unction with the lm~rovèd
operating mechanism of the ln~tant lnventlon,
Fig. ll i a ~omewhat diagrammatlc view of the com-
-8-
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lQ36644
ponent parts of a motor-starter equlpment for controlllng
motor installations with the disconnecting switch shown closed,
and also the contactor assembly being shown in the closed-
circuit position, the truck-mounted elements being illustrated
ln their in-cell operating condition;
Fig. 12 is a top plan view of the reverse-current
~eeder circuit illustrating the structure thereof;
Fig. 13 ls a side-elevational view of the reverse-
!''' current ~eeder structure of Flg. 12;
Flg, 14 i8 a front elevational view of a component
.
part of the improved reverse-current feeder circuit of Figs.
12 and 13;
Fig. 15 is a diagrammatic v~ew illustrating a single-
actlng reverse-current loop structure with the contacts tnot
- shown) closed, and electrical current passlng through the
reverse-current loop structure;
;....... :,:
Fig. 16 illustrates diagrammatically a double- i;
acting reverse-current loop structure utillzing some of the
principles of the present lnvention, but lllustratlng a con-
dition Or a feeder connection structure, whlch is not com-
.... ; . .
~ mercially approprlate or desirable, the contact structure
~ ...... . .
- (not shown) being lllustrated in the closed-circuit position,
and again electrical current belng lllustrated as passing ~ ;
through the double-acting reverse-current loop; ~ ~;
Fig. 17 illustrates diagrammatically the improved
relocation of the feeder circuit structure of Fig. 16, in
which the double-acting reverse-current loop is adversely `
magnetically a~fected by the particular feeder circuit arrange-
ment illustrated in Fig. 17, which is, of course, undesirable;
Fig. 18 illustrates diagrammatically the closed-
.... .. . . . .. . .. .
43,102
~Q3~;6~
circuit;posltion of the vacuum-type circuit-lnterrupter of
the present invention, illustrating the passage of current -
through the reverse-current loop, illustratlng the location
of the pivot point or fulcrum point for the reverse-current
loop arm, with the operating magnet energized, and durlng
the exlstence of hlgh-fault current conditions existing in the
!l
separable contacts of the vacuum-type circuit-interrupter,
the latter being lllustrated as in the cldsed-circuit position;
Fig. 19 is a sectional vlew taken substantially
10 along the line XIX-XIX of Fig. 18; -
Fig. 20 illustrates a de-energized condition of the
vacuum-type circuit-interrupter of Figs. 18 and 19, showing a
relocation of the pivot point or fulcrum point for the reverse
current loop arm structure, and the magnetic repulsive forces
encountered, the view also illustrating the improved ~eeder-
current connections to the reverse-current loop-arm;
. .
Fig. 21 illustrates a fragmentary sectional view
taken along the line XXI-XXI of Fig. 20, lllustrating the
current-flow conditions, and only showing the feeder-current
connector system;
Fig. 22 is a sectional vlew taken substantially
along the line XXII-XXII of Fig. 20 illustrating diagram-
matically the magnetic lines of force associated with the
improved feeder-current system of the present invention;
Fig. 23 illustrates a sectlonal view taken 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 lnvention;
Fig. 24 is an enlarged side-elevational vlew of the
improved movable-contact operator utilized,
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1~)36644
Fig. 25 is a side-elevational view of the improved
- movable-contact operator of Fig. 24;
Fig. 26 is a top-plan view of the improved movable-
contact operator of Fig. 2~;
Fig. 27 is an inverse plan view of the improved
movable-contact operator of Fig. 24;
Fig. 2~ illustrates in side elevation the
accurately-machined lower interrupter support-plate utilized
in the present invention;
Fig. 29 is an inverted plan view of the accurately-
machined interrupter support structure of Fig. 2g;
Fig. 30 is a side-elevational view o~ the improved
accurately-machined interrupter support of Figs. 2~ and 29; ~
Figs. 31-33 are enlarged detail views of the top ;;
~ . . .
interrupter clamp for connecting to the stationary contact
stem of the vacuum interrupter;
Fig. 3~ illustrates diagrammatically the wiring -
.
diagram for the starter assembly of the present invention; and
'r; Figs. 35-37 illustrate an application of the mechan-
.` 20ism to a modified-type of arc-interrupting structure.
` DESCRIPTION OF THE PREFERRED EMBOD ENT
.
The present invention has particular applicability
,` to high-voltage motor starters 1 designed for starting and con-
... .. :~
trolling alternating-current motors. Generally, these ~ ~
..,.. ~, .
starters 1 are supplied in a steel floor-mounted enclosure 2,
such as set forth in Fig. 1. The steel floor-mounted
enclosure 2 may, for example, accommodate two motor starters
1, as actually shown in Fig. 1 disposed in superimposed
relation.
As set forth in Fig. 11, each high-voltage motor-
~.
starter apparatus 1 comprises a cabinet housing 2 in which
high-voltage modular plug-in assemblies corresponding to an
.' . ' -
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-~~ 43,102 ;, ,
lQ3~69~4
isolating-switch assembly 3, a power-fuse assembly 5 and a
contactor assembly 7 are secured. The cabinet houslng 2 ls ,,
illustrated in Flg. 2 as compr~sing panels 9-11 and supporting ; ,-
structure 13 assembled to form a front-entry single-compartment ~
. .
cabinet with access provlded by hinged access doors 15 and ',
17. Mounted on the lnterlor surface of the back panel 10
.
are electrlcal terminal assemblles 19 and 21 whlch electrlcally
engage an lsolating-switch assembly 3 and the contactor
assembly 7, reQpectlvelyO The three-phase output power de-
veloped by the hlgh-voltage apparatus 23 ls conducted through
cables 25, which pass through current transformers 27 to a
load terminal assembly 29 for connection to a remote
electrical clrcuit (not shown). This clrcuit could, of
course, be motor controlled equlpment. Secured,,to the
interior surface of the right-hand panel of the cabinet
houslng 2 ls the low-voltage clrcuitry 31, which is electrlcal-
ly connected through sultable ~ransrormer means 33, to pro-
vide safe access ~or monitoring the operation of the hlgh-
voltage plug-ln assemblies.
~' 20 The hlgh-voltage motor-starter apparatus 23 of Flg.
11, for example, may require a slngle contactor assembly 7,
and therefore supports the compact modular packaging scheme
illustrated, ln which the modular assemblies 3, 5 and 7 can ,,
be quickly removed from the houslng cablnet 2 merely by slid-
lng the assemblles 3, 5 and 7 forward through the cabYnet
opening provided by the access door 15.
The high-voltage motor-starter apparatus, sche- ' ~ ''
matically illustrated in Fig. 11, is set forth, in detail, in - !'
the follo~lng patents: U.SO Patent 3,602~680, issued August
~. . .
31, 1971 to Alfred W. Hodgson; U.S. Patent 3,639,873, issued ~-
-12-
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- - ` 43,102
1~3~644
February 1, 1972 to Alfred W5 Hodgson; UOSo Patent 3,621,339,
lssued November 16, 1971, to Alfred W. Hodgson; U.S. Patent
3,264, 431, issued August 2, 1966 to A. W. Hodgson; U.S.
Patent 3,264,432, lssued August 2, 1966 to A. W. Hodgson et al; ,
U.S. Patent 3,264,433 issued August 2, 1966 to R. D. Clark,
Jr. et al; and U.S. Patent 3,290,468 lssued December 6, 1966
to R. D. Clark Jr. et al.
Sidewalls of the modular assemblies 3,5 and 7
cooperate ln an overlapping relatlonshlp in the cabinet
housing 2 to define two cablnet compartments "A" and "B".
; Compartment "A" is deslgnated the hlgh-voltage component
compartment wlth access provlded by door 15, and compartment
"B" is designated the low-voltage circuitry compartment with
` access provided by door 170
As seen more clearly in Fig. 11, the isolation-
switch assembly 3 comprlses a rotatable handle mechanlsm 35,
which controls the positioning Or electrical contacts 37 to
; engage and to disengage electrical contact with the main power `~
lines which terminate at the electrloal tremlnal assembly 19.
20 The location o~ the isolation swltch assembly 3 ln the cablnet
housing 2 ls selected to position the handle mechanism 35 at
a convenlent operator height. ' '
The handle mechanism 35 ls described ln more detail ; `
in U.S. Patent No. 3,264,431 lssued August 2, 1966, and ; '~
assigned to the assignee of the present lnvention.
Access to the high-voltage compartment "A" is pre-
vented''by an interlock system (not shown) when the handle
mechanlsm 35 is in either the "OFF" or "ON" posltion. Access
to compartment "A" is permitted when the handle mechanism 35
30 is rotated to a horlzontal positlon (not shown). A spring-
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1(~36644
loaded pin (not shown) must be manually depressed before the
handle mechanism 35 can be rotated, thus preventing inadvertent
isolatlon of the handle mechanism. Access to the low-voltage
compartment "B" is provided by the door 17 regardless of the
position Or the handle mechanism 35.
The contactor assembly 7 comprises electrically
isolated contactor poles 39, 41 and 43 which represents
- commercially-available components, such as the Westinghouse
Electric Corporation contactor Type LF-50V430 contactor.
Contactor electrical terminal 45, as illustrated in Flg. 6,
engages electrical terminal assembly 21 to supply voltage
through the cables 25 to the remote load, which may be a
motor lnstallatlon.
The lsolation switch assembly 3 ls slidably
i' positioned within the cabinet housing 2 by outwardly-protrud-
ing flanges which engage horlzontal guide tracks 47 (Fig. 2).
Due to the weight of the contactor assembly 7 lt is
generally lcoated in the bottom section of the cablnet houslng
, 2. The positioning of the contactor assembly 7 withln the
cablnet hou~lng 2 18 accomplished by insertlng the wheels 49,
: whlch are affixed at the four corners of the base 51 of the
, ~ :
assembly 7, lnto the guide tracks 53 (Flg. 2) and rolllng the
; assembly 7 into the cabinet housing 2 until electrical engage-
,~; ment with electrical terminal assembly 21 occurs. ~`
~- The vacuum-type contactor 7 is designed for starting
~ ~ ,
and controlling three phase, 50-60 cycle alternating-current
; motors. The voltage may, for example, be 6,600 and the con- ~ `
tactor-closed continuous rating in amperes 360.
Fig. 3 illustrates ln side elevatlon the rlght-
; 30 hand side 55 of the truck-mounted vacuum-type contactor
' .: '
:, ' ~; '
43,102
~Q366~
assembly 7~ As illustrated in Figo 3, it will be observed that
there is provlded a direct-current operating magnet 57 havlng
a direct-current magnet coil, or operating coil 59.
Assoclated with the magnet structure 57 is a rotatable magnet
armature 61 which makes abutting engagement when the operating
magnet 57 is energized with the magnetic pole-face 63. The -
lower end 61a of the rotatable magnet armature 61 is affixed
by a clamp casting 65 and a key 67 to the external end of an
operating shaft 69, as shown. Also afflxed to the operating ;
shaft 69 is an electrical interlock pushrod 71 which operates
an electrical interlock 73, the purpose for which wlll be more
apparent hereinafter. In addition, Fig. 3 shows a protective
resistor 74 which iæ inserteid into the series magnet coil ~; -
circuit 57 (Fig. 34) when the armature 61 has reached its ,~
fully-closed position against the pole face 63, as illustrated
. :
by the full lines in Fig. 3O Additionally, there is illus-
trated in Fig. 3 another interlock 77, the purpose for which
will appear more fully herelnafter. Also Fig. 3 lllustrates
an isolating-switch m~chanical interlock arm 78, which i9 ..
operable by a downwardly-extendlng interlock rod (not shown)
extending downwardly and operable by the isolating-switch
assembly 3 (Fig . 11).
, Flg. 3 shows that, general, the truck-mounted
contactor assembly 7 comprises two side metallic support
plates 80 and 81 interconnected by a front U-shaped metallic
support channel member 83, which is more clearly illustrated
in Fig. 5 of the drawings. Also Fig. 3 shows the lower stab
~;~ assembly 45 which interconnects the contactor assembly 7 with
statlonary load termlnals 21 (Fig. 2) ~or operating an
external piece of equipment, such as an electr~cal motor, for
-15-
. .
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43,102
1~3669~4
example.
Flg. 4 illustrates the other, or left-hand side 85
of the vacuum-type contactor assembly 7, which includeæ the
other side metallic support plate 80, the two wheels 49 an
interlock bar 87 associated with the levering-in mechanism,
(not shown) whlch constitutes no part of the present invention.
A1BO Fig. 4 lllustrates the control transformer 33 whlch re-
duces the voltage from the llne termlnals Ll, L2 and L3 to a
suitable lower voltage level for operatlng the magnet coil 59
of the operating-magnet structure 57. Addltlonally, Fig. 4
shows the interphase barriers 89-92 a flange æupport plate
95 for supportlng the transformer 33 and also a fuse block
97 for the control circuitry 31. ~ -
- Fig. 5 illustrates a view looking into the front
of the truck-mounted vacuum-type clrcuit-lnterrupter assembly,
or contactor assembly 7. It will be observed that the
armature 61 of the operating magnet 57 ls affixed to the
external end of the operatlng shaft 69 and effects the
rotatable operating motlon thereof. The operatlng shaft 69
; 20 i8, of course, ~ournaled ln sultable bearlngs 99, 101 pro-
vided on the lnner side~ 80a, 81a of the two metallic side
support plates 80 and 81. Fig. 5 more clearly qhows the fuse
block 97, prevlously mentioned ln connectlon wlth Fig. 4, and
also the control transformer 33 for the control clrcuitry 31.
It ls, of course, deslrable to provide contact-
closlng sprlng pressure for each of the individual pole-unlts
39, 41 and 43 in the closed-circuit positlon of the contactor
assembly 7, as illu3trated in Fig. 6 of the drawlngs. Each
pole-unit 39, 41 or 43 is provlded with its own lndlvldual
..
vacuum-interrupter unit 103 and a pivotally-mounted rotatable
-16-
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. -. ~
~3,102
lQ366~ .
contact operating arm 105, which is pivoted upon a statlonary
pivot pin 107 extending between the two downwardly-extendlng
flange portions 108, 109 of a U-shaped lower lnterrupter
support 110, the conflguration of which is more readily
apparent from a study of Figs. 28-30 of the drawings.
The rotatlon 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 afflxed to and rotatable with
, . . .. .
the operating shaft 69. Fig. 5, taken in conJunction with
Fig. 6, more clearly shows the structure of the laterally-
extending cross-bar 112. A~ illustrated in Fig. 6, it will
-- be observed that the cross-bar 112 is preferably of metal,
and in thls particular instance has a square cross-section,
as shown, havlng end plvot-pins 118, the latter being apparent
from a study of Flg. 5 of the drawlngs.
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 Flg. 5. The
lnsulator support 120, ln turn, supports an abutment member
or ln this particlar in~tance a plate 122, for example, having
a configuration more clearly apparent from a study of Fig. 10
of the drawings. Fig. 10 illustrates an exploded view of the
contact-pressure spring assembly 124 and the relation~hip
between the abutment member or plate 122 and a rotatable
reverse-current loop-arm assembly 126, again the configuratlon
of which ls more clearly apparent from a study of Flg. 10 of
the drawings.
As well known by those skllled in the art, it 1
desirable to supply contact spring ~pr eSsSs~urrc on the se bl
"-"; ,:
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'' 1~36~4 ~
contacts in the closed-circuit posltion of the interrupter
103. This sprlng pressure, which is provided ln the lnstant
lnventlon, ls afforded by a compresslon spring 128 -
illustrated in Flgs. 6 and 10, and lnterposed between the
abutment plate 122 and an upper movable sprlng seat 130,
which straddles the two contact-actuating arms 105a, 105b,
r which collectlvely constltute the movable contact-actuating
arm 105 of the interrupter assembly 7. -
It wlll be observed, in connection wlth Flgs. 6, 7
and 9 of the drawlngs, that a contact drlve pin 132 passes
through the two leg portlons 105a, 105b Or the movable
contact-actuatlng arm 105 and, addltlonally, passes through
- a palr Or apertures 134 provided in the rotatable reverse-
current actuatlng arm 136. In other words, the same pivot
pln 132 passes through the two leg portlons 105a, 105b
of the contact-actuatlng arm 105 and also through the leg
portions 136a, 136b constitutlng the reverse-current arm-
assembly 136, thereby enabllng a fulcrum polnt to be exerted
at the plvot pln 132 in the contact-welded condltlon of the
20 separable contacts 138, 139 under certaln condltlons, as
more fully descrlbed herelnafter.
Wlth reference to Flgs. 7, 9 and 10 of the drawlngs,
lt wlll be observed that there ls provlded an overtravel - r
ad~ustlng nut 140, whlch ls threaded upon the upper end 142a
of a contact-pressure stud 142, the lower end of whlch ls
secured into the upper end of the lnsulator support 120.
Thus, in the closed-circuit position of the vacuum-interrupter
assembly 7, as illustrated in Fig. 7, the contact compression
spring 128 is compressed, thereby apply~ng contact-closing
30 pressure between the separable contacts 138 and 139, the
-18-
:' .
\ 43,102
1~36644
overtravel ad~usting nut 140 accommodating the "wide" travel
distance by continued closing travel of the contact-actuating
arm 114. Thus, Fig. 7 illustrates the closed-circuit ~-
positlon of the lnterrupter device 7 with the operatlng
magnet 57 energlzed and the compression spring 128 provlding
the desired contact pressure ln the closed-clrcult posltion
of the devlce. ~-
It wlll be obvious that durlng the openlng opera-
tlon, the operating shaft 69 will rotate in a counterclock-
wlse direction, as vlewed in Fig. 7, carrying downwardly with
- . . .
it the two operating arms 114 and 116 together with the
cross-bar 112 and the three insulator supports 120. Also
. . ~.: ~
carried downwardly will be the abutment plates 122 and the -
contact pressure studs 142 until the overtravel ad~usting
nuts 140 engage the yoke portions 130 of the contact actuating
- arms 105, as illustrated in Fig. 9 of the drawings.
.
~- Assumlng that there does not exlst a welded condltion at the
separable contacts 138, 139, the operating mechanism 144 will ~ ~ .
contlnue its counterclockwlse openlng movement carrylng the
20 separable contacts 138, 139 to thelr fully-open clrcult
- position, as lllustrated ln Flg. 9 of the drawlngs.
. ~ . .
The interrupter unit 103 may be of any sultable type
manufactured commercially by a number of companles, and, ln
general, comprises an evacuated envelope 145 having end
metallic plates 146, 147 hermetlcally sealed to the ends of
the insulating envelope 145 ~ such as a ceramic sleeve, for
example. The vacuum "bottle" 103 ls provlded havlng support-
lng stud portions 149, say three in number, for example,
. . .
; extending upwardly and downwardly, as illustrated in Flgs. 7
and 9, and also havlng the movable contact stem 150 extending
19
. - . .: . -
.
,.- . . :
43,102
' - '
366~4
externally, as illustrated ln Flgso 7 and 9. In lts manu-
factured component assembly form, lt 1R, therefore, provided ~;
ln a form enabllng lts ready mounting by the six mountlng
studs 149 and the movable contact 139 may be opened and closed
by an actuatlng clamplng portion 152 secured to the extending
end 150a of the movable contact stem 150. The present equip-
ment utilizes preferably, one of these manufactured "bottles"
1~3 for each pole-unlt 39, 41, 43. As lllustrated in Flg. 6,
there ls provlded an upper interrupter support castlng 154,
cast, ln thls partlcular instance, of aluminum, which has a
horlzontally-extendlng apertured support-flange portion 154a
havlng mounting poles 154b therein to accommodate the three
upwardly-extending mounting studs 149, the latter, as
mentloned, constltuting a part of the manufactured bottle
103.
Mountlng nuts 156 threadedly secure the support- -
flange portlon 154a of the casting 154 to the vacuum "bottle" -
103 and maintain it flxedly in a proper position. The
. .
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 support 158 (Fig. 6) and
to a metallic conductor support strap 160, the latter belng
securely mounted to an upper fuse-flnger terminal assembly,
generally deslgnated by the reference numeral 162, and
illustrated more clearly ln Fig. 6 Or the drawings. As
. :~ .. ,
illustrated in Fig. 11, ~he fuse-finger assembly 162 accom-
modes a power fuse 164 for each of the individual pole-units
39, 41, 43 of the equlpment 7. A fuse-finger contact-
pressure spring 166 is utillzed, as illustrated in Fig. 6,
-20-
'
43,102
. ~ ',.
~)36~44 ~:~
.
supported between the pivotal fuse-finger portion 168 of the ~
terminal assembly 162 and a spring seat 170 associated with -
a mounting bolt 172, the latter extending through a
vertically-disposed insul spacer block 174, the latter being
secured by mounting bolts 172, 176 to a laterally-extending
insulatlng suport plate 178 of the fram 180. In addition,
a metalllc angle 181 is provlded to rigidly lnterconnect the
horizontally-extending line-connectlon strap 160 with the
horizontally-extending conductor strap 182, Fig. 6 again
. . .
showing this construction more clearly. A mounting bolt 184
extends vertically through the several component parts, as
also shown in Fig. 6.
Fixedly secured to the upper extremity of a line- -~
connection strap 160 is a terminal clamp 186 havlng a ~
clamping portlon 186a whlch encircles the upper extending
end 188 of the stationary contact stem 189, as more clearly
:; shown ln Fig. 7. Due to the inherent flexlbllity provlded
.... . ..... ..
by the line-connection strap 160 (Fig. 7), there ls not
exerted any stress nor torqueing action upon the ~tationary
contact stem 188. However, with reference to Fig. 7, it will
be observed that the bottle structure 103 itself is rlgldly
supported by the relatlvely masslve and heavy upper lnter-
rupting casting support 154.
To counteract the lnward closing force exerted
because of the evacuated environment 190 wlthln the evacuated
enclosure 145, a klckout spring 192 ls provlded to compensate
; for the atmospheric pressure, the latter, of course, tending
to force the separable contacts 138, 139 lnto the closed-
circuit position, as illustrated in Fig. 7. The kickout
; 30 spring 192 ls interposed between a lower metallic washer 193
-21-
:'`. ' -.
- , - - - - - . - . . . . . . . . .: .
` 43,102
,' ' ~''
~` ~Q36644
and the upper end of contact operator 152.
With reference to Figs. 6, 7 and 9 of the drawlngs,
lt wlll be observed that there is provided at the lower end
of the contactor-assembly 7 a reverse-current connector-
assembly 126 comprlsing a generally loop-shaped flexible
connector 195 having an upper terminal 196 fixedly secured
by a connector bolt 197 to the lower end of the movable
contact operator 152. The flexible connector 195 extends
rightwardly, as viewed in Fig. 7, into a loop portion "L",
and then extends toward the left, as viewed in Flg. 7, to be
secured by a connector bolt 199 to the mid-portion 200
(Fig. 12) of a stationary U-shaped current-feeding member
`4 :.
generally designated by the reference numeral 201 and having
a configuration more readily apparent from a study o~ Flgs.
1?-14 of the drawings. ~ -
- With reference to Fig. 16 of the drawings, lt wlll
~- be observed that placlng the load-connectlon feed member 203
toward the front of the contactor assembly is commercially
~; inappropriate. Also, as set forth in Flg. 17, providing the
constructlon as set forth therein~ with a relatively close
spacing "S" between the stationary portlon 205 of the
reverse-current loop-connector 207 and the feed-strap member
208 provides an undesirable neutralizatlon effect, as
determined by the distance "S" ln Fig. 17.
The more deslrable form is as indicated in Fig. 18 of
the drawings, where the current-feed structure 201 comprises a
pair of stationary 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 portlon at the front
thereof, deslgnated by the reference numeral 200. The bight
-22-
"'''.,
.;
` 43,102
~036~44
portlon 200 is electrically connected to the lower termlnal
198 of the loop-shaped reverse-current loop assembly 126, as
lndicated more clearly ln Fig. 9, whlch has the deslrable
advantage, as seb forth in Flgs. 21 and 22 of the drawings, -
- namely an augmentation of the upper movable flexible strap -
portion 219 by the magnetlc field around the leg portlons
221, 222 of the U-shaped reverse-current feed structure 126.
It wlll be observed that the reverse-current loop
force "F" acts to break contact welds when the magnet
structure 57 is de-energized, as is the condition set forth
in full lines in Fig. 20 of the drawings. Under this
particular state of affairs, the force "F" acting is such '
as to create a fulcrum point at the pivot point lOi, thereby ``
tendlng to create a counterclockwise rotative action upon
the reverse-current arm 136, thereby bearing agalnst the
abutment plate 122, and asslsting the acceleratlng sprlngs ~ s
128 and the operating mechanism 144 in effecting a separation
of the contacts 138, 139 within the vacuum-interrupter 103.
By avoiding the utillzatlon of relatlvely-heavy
springs, which ln and of themselves would be ¢apable of
breaking welds, avoidance of a heavy operating mechanism 144
is advantageoùsly obtained. That is, if relatively heavy ;; ~-~
accelerating springs 128 are utilized, it would take a con- ;
siderably stronger operating mechanism 144 to effect their
compression, and thereby bring about the closed-circuit con-
dition of the contactor assemblage 7.
In the closed-circuit position of the interrupter,
as shown in Flg. 18 9 with the operating magnet 57 energized,
the fulcrum polnt ls relocated so as to effect a desirable
increase of pressure at the separable contacts 138, 139
-23-
` 43,102
~.~)3664~
during the attainment of heavy-fault current conditions. At
thls time the fulcrum point ls at the movable contact plvot
pln, as designated by the rererence numeral 132 ln Flg. 18. --
Wlth reference to Flg. 11, the flow of electrical
power through the starter 3 can be traced by referrlng to
Fig. 11, where the starter 3 is shown in the energized
position. The line stab assembly 19, mounted at the back of
the cabinet 2 also serves as the starter line terminals Ll,
L2 and L3. The stabs themselves are engaged by the fuse
~aws 223 of the lsolation switch 3 which is mounted on rails
at the top of the cablnet 2. The llne ferrules 224 of the
Type CLS power fuses 164, cllp into the fuse ~aws, and the
load ferrules 226 fit into the fuse holders 162 which are
part of the contactor line terminals. Power flow through
the contactor 7 is from the load ferrules 226 of the power
fuses 164, through the interrupter contacts 138, 139 shunt
195 and then to the contactor load terminals 45. The con-
tactor 7 is mounted on rails 53 in the lower part of the ;
cabinet 2, immediately ad~acent to the current transformers
27, which are bolted to a panel 9 1n the side of the cabinet2, with the }oad terminals 21 for the starter 1.
Spring-loaded contact ~aws 228 (Fig. 6) mounted on
the contactor load terminals 45 plug into a lower stab
assembly 21, provlding a convenient connection to the motor
load terminals Tl, T2 and T3.
Electrical protection ls provided by the Type CLS
power fuses 164 and by the overload relay 230. The CLS
current limiting power fuses 164 have a speclal time/current
characteristic for motor service, and this characteristic is
coordinated with the characteristic of the overload relay 230.
-24-
~''`'. '~
~~ 43,102
'' . , , . '
11~36644
Currents greater than full load motor current, up through
locked rotor current, will operate the overload relay 230
and trlp the contactor 7 before the fuses 164 blow. This
prevents unnecessary blowlng of the fuses 164. Since the
lnterruptlng capaclty of the contactor 7 is 50,000 KVA, the
power fuses 164 must operate faster than the overload relay
230 when current exceeds thls value, ln order to prevent
damage to the contactor 7. In all faults above 50,000 KVA -
and wlthin the ratlng of the equipment, the CLS fuses 164
will operate flrst.
The current transformers, overload relay heaters,
and power fuses are coordlnated wlth the motor characterlstlcs,
so that the starter 1 must be used wlth the motor for whloh
;,, . :. . '
lt was designed. Motors wlth special character~stic or loads
requlring special protectlon often require other or additlonal
protectlve relays.
j Vacuum contactors are relatlvely new on the market
'~ and have en~oyed only llmlted success dur to several short-
. .
comlngs.
In an efrort to mlnlmize the most ~erious of the~e
shortcomings, the vacuum interrupter manufacturers have found
lt necessary to use contact materlals whlch are susceptlble
to welding.
; The weldlng problem, however, can be minlmlzed by
the use of contact and weld breaking forces approximately ten
tlme~ those usually found ln a conventional alr break contactor
, :
of comparable rating.
, Vacuum lnterrupters havlng the most deslrable
,.......................................................................... .
lnterruptlng characterlstics and longest contact life have
been found to weld at currents considerably below their
-25-
. . .
43,102
':
1036644
lnterruptlng llmit, so the lnterrupting rating of a contactor
uslng these lnterrupters is limited by the ability of the
actuating mechanism to overcome the weldlng problem rather
than by the arc interrupting ablllty of the lnterrupter.
A three-pole contactor havlng a magnet and frame
assembly proportloned to meet the design requlrements of the
requirements of the vacuum interrupter and still have a -
reasonable mechanical life would be much too large and
costly to compete with exlstlng alr-break contactors whlch
- 10 requlre only a fraction of the contact force. As a result of
this "squeeze," presently avallable vacuum contactors are a
deslgn compromise which do not completely satisfy the requlre-
ments of the vacuum lnterrupter and as a result do not perform
as well as exlstlng alr-break contactors.
The very hlgh contact forces mentloned above are
requlred only when lt ls necessary to obtaln the maximum
momentary rating of the vacuum lnterrupter whlch is ln the
event of a power system fault. Slnce the contactor may seldom
see thls condltion ln a¢tual servlce, a contactor designed to
-- 20 contlnuously provlde these hlgh forces would represent a
rather lnefflclent use of space and materlal.
A reasonable-slzed magnet coupled to the lnter-
rupter shaft through a toggle mechanism or other system of
levers could be advlsed to develop hlgh contact force, but -
the hlgh mechanlcal advantage of this mechanism would act
to reduce the contact operating speed far below the values
~ ~ .
recommended for the vacuum lnterrupter. The hlgh mechanlcal
advantage of this mechantsm would, ln addition, result in
low contact overtravel whlch in turn would make frequent
adjustment of contact overtravel necessary. ;~
-26-
. ,~ ' .. ' .
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.', '.
. .
lQ36644
Reverse current loops slmilar to the one shown in
Flg. 15 have been employed in the past to increase contact
force under heavy fault conditions, but have the tendency to
override the operating magnet. A reverse current loop 232
(Fig. 15~ of this type, designed to supply the required
contact forces of a three-pole vacuum contactor, would exert
so much force that the reverse current loop 233 would hold
the contacts and magnet closed even after the magnet is de-
energlzed. A weak reverse current loop 233 of this type
would not hold the contacts closed, but would act to reduce
opening speed and weld-breaklng forces, which is also unde-
i slrable.
In the disclosed vacuum contactor design 7 (Fig. ;~ ;-
20), contact sprlngs, operating magnet and contactor frame
details are proportioned to provide contact forces sufficient
to insure satisfactory performance under startlng, running,
and locked-rotor conditions for the maximum size motor with
which the contactor 7 will be used.
These are the operating conditions the contactor 7
wlll see in everyday service, and the mechanical forces which
the operating mechanism must be able to endure Por a million
or more operatlons.
; Occasionally the contactor 7 may, however, be sub-
~ected to power-system fault conditions in which event the
contactor 7 may be called on to interrupt or withstand peak
currents 10 times or more the maximum peak currents en-
- countered in everyday service under locked-rotor or motor-
... .
startlng conditions.
In order to handle these higher currents, the
vacuum interrupter 103 will require much higher contact and
` ` 43,102
:`
' la36644
weld breaking forces than were necessary for handling the
normal motor currents encountered in everyday service. ;
To obtain the higher mechanical ~orces only during
an occaslonal system fault, without increasing the mechanical
forces in e~ect in normal operation, a novel reverse current
loop ls provided as shown in Fig. 20.
This reverse-current loop 126 provides an increase
in contact force and also weld-breaklng force which is in
proportlon to the square of the current "I" flowing through
the reverse current loop.
By properly proportioning the reverse-current loop ~,
126, it is possible to provide a substantial increase in the
contact and weld breaking forces under hlgh-current conditions -
while only slightly increasing these forces under normal
operating conditlons.
The reverse-current loop 126 consists of upper and `~
lower shunt legs 221, 222 plus parallel load connectlon bus
bars 210, 211 as shown in Figs. 12 and 20.
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 varlous 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 strlkes ~; -
' the right-hand end o~ the reverse-current loop-arm 136.
When the contactor 7 is sub~ected to a power system
fault, of high current magnitude, the reverse current loop
30 126 will apply a force upward on the right-hand end of the ~ ;
-28-
. ~ .
`` 43,102 ~ i
'
, -
1~3669~
- reverse-current loop-arm 136 which will in turn pry the inter- -
rupter contacts 138, 139 closed as shown ln Flg. 17 assuming the
contactor magnet 57 remains closed.
A second reaction of the reverse-current loop-arm
136 is to apply a downward force on the contact spring support
plate 122 which wlll in turn increase the openlng veloclty of
the magnet and cross-bar assembly 112 once the magnet 57 is
de-energized.
When the magnet 57 is released, the moving assembly
ls accelerated by the comblned forces of the contact springs
128 and reverse current loop 126 until there is no gap at the
; contact overtravel ad~ustlng nut as shown ln Flg. 20.
At this point, the klnetic energy of the moving
system imparts a hammer blow to the contact actuating arm 105
~ which acts to break any contact welds which might exist.
- When the overtravel ad~usting nut 140 makes con-
tact wlth the upper contact spring seat 130, as shown in
^ Figure 20, the function of the reverse current loop 126
automatically takes a complete reversal to apply an additional
contact openlng force to the lnterrupter 7 rather than a con-
tact closlng, as lt prevlously had done when the magnet 57
was closed.
Use of a flexible shunt 195 doubled back on itself
in a conventional manner as shown in Fig. 16 brings the load
, connection 203 out the front of the contactor, which is
undesirable for use with plug-in devices.
Doubling the load connection back under the lower
leg of the shunt 195 as shown in Fig. 17, acts to weaken the
magnetic fields and mechanical forces o~ the reverse current
loop 207 unless dimension "S" is made relatively large.
-29-
''' '~ ' ''''
` 43,102
.
~(~36644
The disclosed design employs a novel arrangement of
the current-carrying parts 210, 211 of the reverse current
loop 126 which makes it possible to bring the load connections
45 out at the rear of the contactor 7 and at the same time
increase rather than decrease the ~orce o~ the reverse current
loop as shown in Fig. 22.
In this design the connection ~rom the contactor
load terminal 45 to the lower leg 222 of the shunt 195 is
dlvided into two parallel legs 210, 211 which straddle and
are mounted at the same elevation as the upper leg 221 o~ the
shunt.
The magnetlc fields of the two parallel connections
210, 211 to the load terminal 45 combine with the magnetic
fields surrounding the shunt 195, as shown in Fig. 22 to
shape and to strengthen the resulting magnetic field of the
' reverse current loop 126 in such a manner that the net
.;. ,'. ::
s reverse-current loop force "F" ls greater than for the con-
.~ ,~ . ..
ventional reverse-current loop shown in Fig. 16. ~`
- A kickout sprlng 192 ls mounted directly 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, 139. Without a kickout spring 192 in this lo-
cation, the contacts 138, 139 could touch momentarily under
low contact force conditions while play is being taken up in
the operating mechanism 144. Play between the contacts and
operatlng mechanlsm 144 would aggravate the contact erosion
and weldlng problems both on the opening and closlng
operations.
The kickout springs 192 also minimize armature
bounce on openlng and in addition are proportional to apply
~ ~3~ `
: ' ',;
: ' '
` 43,102
:
:
1(~;31~;644 :
sufflcient load on the magnet 57 at open gap position to
prevent the magnet 57 from picking up unless its operating
voltage is sufficlent for the magnet 57 to seal-in from the
contact-touch posltion.
Each pole 39, 41 and 43 of the contactor may be
installed or removed from the contactor as an individual sub-
assembly, so that it may be efficiently assembled or main-
tained at a work-beach rather than ln the contactor 7.
. .
; The interrupter unit itself may also be installed
or removed from the contactor as a smaller sub-as~embly con-
sisting of the interrupter 103, its support 154, moving
contact actuating arm 105, and reverse current loop details
126 as shown in the exploded view of Fig. 10.
In order to obtain maximum mechanical life of the
interrupter bellows 235 and also avoid friction between the
interrupter contact shaft 150 and its bushlng, it is important ,
that the relatlonship between the contact drlve pin 132 and
the plvot pin 107 for the contact actuating arm 105 be
; accurately maintalned.
To accomplish this, the lnterrupter 103 and the
,. . .
.; contact actuating arm 105 are both mounted on a single rlgld
.; . .
mechanlcal detail 110 which can be accurately manufactured.
This detail 110 is the lower interrupter mounting bracket
shown in Figs. 28-30.
In connection with the above allgnment of parts,
it is also desirable that the contacts 138, 139 touch when
the contact drive pin 132 ls on the same horizontal center-
line 237 as the plvot pin 107 for the contact-actuating arm
105.
When the interrupter sub-assembly is being
-31~
`'~' .
. . . ~
~ 43,102
~lJ3664~
assembled, the kickout spring 192 is placed over the contact
shaft 150 and then compressed by the contact operator 152
which ln turn is held in place by the shoulder bolt 239. The
- shoulder bolt 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 239
. design is coordinated ln a manner that the shoulder bolt 239
cannot clamp 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 applying 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 pin 132 is installed, the
contact actuating arm 105 is depressed to take up the play ~ ~
; between the contact drlve pin 132 and contact shaft 150 .;
~: .
; following which the contact operator 152 ls clamped to the
contact shaft 150 by tightening the clamplng bolt 241. ;:
; In normal servlce, the contact shaft 150 wlll be ;~
actuated through the clamped ~olnt between lt and the contact : .
: .
operator 152, but should this ~oint fail the contacts 138,
139 will then be closed by compression of the parts between
the drive pin 132 and the end 150a of the contact shart 150, ~:
and opened by the shoulder bolt 239.
One of the ob~ects of the present invention ls to
,.
prevent excessive torque from being applied to the shaft 150 :~
of the interrupter 103 during malntenance and/or assembly :~
since torque may destroy or shorten the mechanical llfe of .
the interrupter bellows 235. :-
The shoulder bolt 239 acts as an assembly fixture
: -32- -
.' '~ .
` 43,102
..
~'
: ~36644
to compress the kickout spring 192 durlng assembly while
still allowing the contact operator 152 to be rotated as ~:~
required to install the contact drive pln 132. In operation
the shoulder bolt 239 in addition acts as a safety device :;~
to insure opening of the contacts ln the event the contact
- operator 152 ls not securely clamped to the lnterrupter con-
tact shaft 150. -~
' The interrupter 103 is rlgidly supported at its
. upper end, which contains the interrupter stationary contact
`.......... 10 138 so as to avoid transmitting contact forces through the
walls 145 of the lnterrupter 103. The moving contact end
150 of the lnterrupter 103 in addition is clamped to the
statlonary portion of the pole assembly to provide lateral ::-
stability. Clamping of the lower end of the interrupter
sub-assembly "SB" is accompllshed by means of an oversized
~ open slot 243 whlch compensates for the manufacturlng
'~; tolerances of the interrupter 103 and also simpllfies instal-
lation and removal of the interrupter sub-assembly "SB".
Manufacturing tolerances on the interrupter length
dimension "X" are rather large, so khe vertlcal locations of
the lower ends of the lnterrupter 103 may vary considerably
: from contactor 7 to contactor 7 and from pole to pole. Since
the operatlng mechanlsm 144 for each pole is mounted on the
moving contact end "E" of the indlvidual interrupters 103,
rather than on some fixed portion of the pole assembly, thiS : `
is of little consequences. - ~ .
;~ In the event the interrupter length "X" is found to
be other than lts nominal value, the final lengths of the con-
tact springs 128 will also vary from their nominal value
resulting in elther h~gh or low contact forces.
;: -33-
~; ;
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,
~036644
The average contact force in the case of a multlple-
~` pole contactor~ as shown ln the drawings, can, however, be
corrected by adJusting the angular position of the magnet
armature 61 on the operatlng shaft 69 so that the correct
- average contact spring length and force 128 is obtained when
the magnet 57 ls sealed-ln. ` -
Angular posltion ad~ustment of the magnet armature
61 is a standard ~eature of an existing air-break contactor
magnet 57 applied to the disclosed vacuum contactor 7.
Variatlons in contact ~orces between poles existing
after the magnet ad~ustment 61 has been made will fall within
allowable limlts lr the contact springs 128 are designed to
have a low spring rate.
NON-TORQUE ACTION EXERTED BY SHOULDER-BOLT 239 ~;
To avold lmposing torque action upon the movable
contact stem 150 and thereby exerting corresponding torque
action upon the bellows 235, the utllization of a novel
shoulder-bolt 239 ls provided. The construction of the
shoulder-bolt i8 set forth in Figsi 9 and 23 of the drawings.
It wlll be observed that the bore 245 of the contact-shaft
operator 152 has a relatively loose fit on the contact stem
150 as shown in Flg. 23, the shank 239a of the shoulder bolt
239 has a loose fit at "Ct' wlth the movable contact operator
152. The shoulder-bolt 239, for example, may have an Allen
hèad wlth an enlarged portion 239a and a reduced portion 239b
with a shoulder 247 therebetween, so that the shoulder-bolt,
` when tlghtened, will ~orce washers 249 (Fig. 10) against the
lower extremity 150a of the movlng-contact shaft 150 of the
vacuum-type interrupter 103. Th1s is shown in Fig. 23. The
.. . ..
number of washers 249 is arranged to accommodate the
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tolerances provided between the different movable contact
shafts 150 of the several pole-units 39, 41 and 43. Once the
shoulder-bolt 239 is tightened, the contact-shaft operator
152 ls moved manually upwardly, so that there is no clearnace
at the polnt"D" in Fig. 23. Then the clamping bolt 241 of Fig.
: 10 is tightened, so that the movable contact shaft 150 is
operated by the contact-shaft operator 152, the latter
having the apertures 250 provided therein to accommodate the
center-line of the contact-drive pin 132. 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. There may, of course, be relatively
wide tolerances provided in the vacuum-bottle manufacture,
and the foregoing arrangement permits a desirable accommodation
of these tolerances.
~: VACUUM-BOTTLE TOLERANCES
Due to the wlde latitude of the tolerances provided
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 of any of the hermetlc seals 251. To
effect this end, an accurately-machined lower-interrupter
support-plate 110 having the pivot apertures 252 provided
.
therein is supplied. These pivot apertures 252 may be
accurately machlned, and once the vacuum bottle 103 is fixedly
secured by the upper interrupter castlng 154, as a first
operation, subsequently, as a separate operation3 the
U-shaped accurately-machined support plate 110 is secured
into place by the lower three mounting bolts 149. The pivot-
pin 132 may then be accurately located with respect to the
lower interrupter support 110 because of the accurate machining
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of the pivot apertures 252 therein.
Thls wlll accurately locate the contact-actuatlng , -
lever 105 and, addltlonally, accurately locate the contact- ~:.
stem drlvlng pin 132. As mentioned previously, the contact-
shaft clamp bolt 241 i5 tightened as a flnal operation after
prevlous assemblage of the contact-pivot pin 132 and
tightenlng of the shoulder bolt 239.
WIRING CIRCUIT DIAGRAM FIG. 34
Included ln the wiring clrcuit diagram of Flg. 34 ~;
ls a power-operated main contactor 7 wlth separable power
contacts 138, 139 to connect the three-phase load-llnes Tl,~ :
T2, T3 to the power-line conductors 254, 255 and 256, whlch
are normally connected to the main supply lines Ll, L2 and
L3, through a disconnecting or isolating switch 3 including
an arrangement of main power fuses 164 and sets of comple-
mentary dlsconnecting contacts 223 (Fig. 11).
Contactor 7 includes an electromagnetic operator .; ::
57 havlng a coil 59, which is energized by a rectifier 259
in responqe to the operation of a normally-biased-open push-
button "START" switch 261. Closure of the "START" switch 261
energizes a relay 263 whose normally-open contacts 265 and
267, respectively, connect the output of the rectlfier 259
to the operator 59, and the input of the rectifler 259 to the . .
secondary 269 of a stepdown transformer 44, whose primary 271
ls connected across one phase of the main power-lines Ll,
,: .
L2 and L3. The input to the primary 271 includes fuses 273.
The electromagnetic operator 263 of the contro~ re-
lay i8 normally energized from the transformer secondary 269, "-
;but may also be energized by a separate source of control
power 275 for test purposes.
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Included in the output circult of rectifier 259 are the -
normally-open contacts 265, male-female type plug disconnects
277, and resistor 279 shunted by a delayed-break auxiliary
contact 281 mounted on the magnet assembly 57.
A hold or latch clrcuit 283 is shunted across the
"START" button 261 and in¢ludes male-female plug-type discon-
nects 285 and normally-open contacts 287, which are operated
to close thy circuit 289 across the "START" button 261 when
contactor 59 is operated, thereby holding relay 288 and con-
sequently contactor 59 ln the operated energized condition.
When contactor 7 closes, delayed-break auxiliary
contact 286 openB to insert protectlve resistor 279 in series
with the holding coll 59.
The thermostatic switch 290 is an overload switch
and responds to the overload current conditions Or the load
lines Tl, T2 and T3, as manifested in the heating of resistors
` (not shown) energized respectively from the current trans-
formers 27.
From the foregoing description lt will be apparent
20 that there has been provlded an improved operating mechanism
for the separable contacts of a circuit-interrupter, parti-
cularly applicable to one Or the vacuum-type. Although the
instant invention has been described in connection with a
vacuum-type circuit-interrupter 10 3, it will be obvlous to
those skilled in the art that certain principles, involved in
the present disclosure, are pertinent to many other types of
lnterrupter units, say those of the air-break type, such as
illustrated in Figs. 35-37. In these figures, gas-evolving
materials are utillzed instead of an evacuated environment.
,~ 30 However, the desirable conditlons for effecting the breaking
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o~ welds, or the addition of contact-pressure spring-force
in the closed-circuit position of the lnterrupter, when the
magnet ls energized, is accomplished in a manner similar to
that described heretofore.
Wlth referenct to Figs. 35, 36 and 37 lt wlll be
-` observed that there is provided an air-break circult-
interrupter 300 havlng a hollow movable contact 301 pivotally
connected, as at 132, to the movable contact-actuating arm
105 in a manner ~imilar to that heretofore described in
connectlon with Flgs. 6, 7 and 8 of the drawings. The
movable contact 301 makes separable contacting engagement
wlth a statlonary contact member 303. The movable contact
301 moves downwardly durlngthe openlng operatlon through
a generally tubularly-shaped member 305 ~ compo~sed of gas- -
evolvlng material, such as flber, Delrln, Celcon/ or llke
gas-evolving materlals, as deslred. In addltlon, a follower
member 310, more clearly shown in Flg. 36, ls secured by
a metalllc rod 312, as at the pivotal pln location 315.
; Durlng the openlng operatlon, as in the manner
20 hereto~ore descrlbed ln connection wlth Fig. 7, the movable
tubular contact 301 moves downwardly carrylng wlth lt the
plvotally-mounted follower member 310, the latter also belng
composed Or gas-evolving materlal. An arc ls establlshed,
and the arc ls extlngulshed by the gas evolutlon resulting
from the interaction between arc and the surrounding gas-
evolving materials. An annular coil 320 may be electrically
; lnterposed between the relatively stationary annularly-shaped
contact 303 and a lower-disposed arcing plate 325 to provide
a radial magnetic fleld to bring about the rotation of the
30 established arc, and consequently a more intimate engagement
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thereof with the surrounding gas-evolving material definlng
an annular arcing 330 chamber. As will be obvious from an
inspection of Fig. 37, the annular arcing member is provlded
between the outer surface of the insulating follower member
310, composed of gas-evolving material, and the inner surface
of the surrounding insulating cylindrical member 305 also
composed of gas-evolving material, as mentioned.
The mechanism 144 may be of the same type as here-
tofore described in connection with the vacuum-interrupter
1( 103. Also, in the closed-circuit position of the device,
with the contacts 301 and 303 in a welded condition, again
the augmentation of the reverse-current loop-arm assisting
the operating mechanism 144 is desirable in breaking any welds
established at the separable contacts 301 and 303.
; Certain addltional details regarding the inter-
rupting structure only of Figs. 35 and 37 are set forth in
United States Patent No. 2,294,801, lssued September 1, 1942 to
Herbert L. Rawlins, and assigned to the asslgnee of the
instant application.
Also, it will be observed that with the lmproved
operation mechanism, and the reverse-current loop system, the
function of the reverse-current loop-system changes in
dependence upon wheteher or not the oepratlng magnet 57 is
energized, or is not energized. In the energized state of the
operating magnet 57, an addltlonal force ls provlded to
malntain the contacts 138, 139 closed durlng the exlstance of
heavy-fault-current conditions. When the magnet 57 is not
energize~,the fulcrum point changes, or is relocated to there~y
provide, instead of a closing force, in this instance an
opening force, which assist and augments the accelerating
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opening springs. -~ :~
Although there has been illustrated and described ~::
speciflc embodiments of the lnvention, it is to be clearly
understood that the ~ame 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 invention.
.
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