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Патент USA US3090862

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May 21, 1963
F. KRETZSCHMAR
3,090,854
PERMANENT MAGNET BLOWOUT FOR A CONTACTOR
Filed NOV. 21, 1960
I5 Sheets-Sheet 1
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INVEN TOR.
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May 21, 1963
F, KRETzscHMAR
3,090,854
PERMANENT MAGNET BLOWOUT FOR A CONTACTOR
Filed Nov. 21, 1960
3 Sheets-Sheet 2
4'
7°
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INVENTOR.
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May 21, 1963
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3,090,854
F. KRETZSCHMAR
PERMANENT MAGNET BLOWOUT FOR A CONTACTOR
3 Sheets-Sheet 3
Filed Nov. 21, 1960
INVENTOR.
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United States Patent Gifl1€€
2
1
3,090,854
PERMANENT MAGNET BLOWOUT FOR
A CONTACTOR
Frederick Kretzschmar, Nanuet, N.Y., assignor to Ward
Leonard Electric Co., Mount Vernon, N.Y., a corpora
tion of New York
3,ti%,854
Patented May 21, 1963
magnet or otherwise suitably actuated. The contact but
tons are located in the cavity 13 between the side por
tions and transfer the current from one contact to the
other, and on separation of the contacts an arc may be
formed between the contact buttons. The are quenching
device may be used with other types of contacts and its
use is not restricted to the form illustrated and described
herein.
The side portions 11 and 12 have inner walls 20, 21 and
the intermediate portion 14 has an inner end wall 22.
This invention relates to blowout devices for quench
ing a spark formed on separation of two conducting 10 The side walls and end wall de?ne three sides of the
cavity. There is an opening 23 at the top of the cavity
electrical contacts.
and an opening 24 at the bottom. The ends of the side
It is well known that a circuit tends to maintain the
portions form an end opening 25 through which the mov
current across two contacts as the contacts are separated
able contact 18 enters the cavity 13. The contact 17
to produce an are. This arcing causes the engaging
15 enters the cavity through the lower opening 24.
surfaces of the contacts to become pitted, thereby reduc
As best illustrated in FIG. 5 the ?xed contact 17 is
ing the amount of current the contacts are capable of
positioned in the middle of the cavity with the contact
passing without overheating and causing the surfaces to
button 26‘ adjacent the end wall 22. The movable con
unevenly engage. Various means may be provided to
prevent or stop this sparking and reduce its adverse 20 tact 18 may be positioned above or below the ?xed con
tact and moves in and out of engagement with the ?xed
affects. One method is to produce a magnetic ?eld ex
contact through a stroke within the cavity 13.
tending transverse to the relative movement of the con
As illustrated in FIG. 5 the pairs of contacts are in
tacts which quenches or extinguishes the are.
side by side relation. The side portions ?t between the
An object of this invention is to provide a spark
quenching device that is small and easily mounted on 25 pairs of contacts. The side walls 2%, 21 and end wall
22 of each holding member form an arc barrier between
a contactor or relay and has a magnetic ?eld for quench
the pairs of contacts.
ing the are formed between separating electrical con
The side portions have sui?cient thickness for form
tacts.
ing recesses 30, 31 in which the magnets are located.
Another object of this invention is to provide an arc
The recesses 30, 31 are rectangular in shape and are de
quenching device comprising a few parts.
30 ?ned by side walls 34 and end wall 35 in side portion
Other and further objects of the invention will be ap
11 and side walls 36 and end wall 37 in side portion 12.
parent from the following description taken in connec
The side walls are narrow to form a shallow recess. The
tion with drawings in which:
magnets are rectangular and approximately the same
FIG. 1 is a perspective view of the single piece hold
size as the recesses. The end walls 35 and 37 have
ing member supported by a bracket;
35 grooves 38, 39 adjacent the side walls forming the raised
FIG. 2 is a sectional view taken along lines 2—2 of
centers 40, 41. The magnets 32, 33 ?t in the recesses
the embodiment of FIG. 1;
and are securely fastened to the supporting member by
FIG. 3 is another sectional view taken along lines 3-3
Filed Nov. 21, 1960, Ser. No. 70,508
6 Claims. (Cl. 200-147)
means of an epoxy resin on the centers 40', 41. The
of FIG. 2;
FIG. 4 is a top view of the single piece embodiment of 40 grooves 38, 39 extending around the centers 41}, 41 pro
vide space for the excess resin so that the resin does not
FIG. 1;
?ow to the outside surfaces. The outer surfaces of the
FIG. 5 is a diagrammatic illustration of the relation
magnets and the respective side portions are generally
ship of the contacts to the permanent magnets and the
magnetic ?eld;
even.
The width and length of the magnets are slightly less
FIG. 6 is a perspective view of the two piece holding 45
than the width and length of the side portions so that
member separated for purposes of illustration;
the magnets horizontally overlap with the entire cavity
FIG. 7 is a perspective view of one of the pieces of the
13. The permanent magnets may be of any permanently
holding member of the second embodiment;
magnetizable material. However, to secure all the ad
FIG. 8 is an end view of the assembled two piece em
vantages of the invention it is preferred that the non
bodiment supported by a bracket;
conducting ceramic type be used. Thus the magnets and
FIG. 9 is a sectional view taken along lines 9--9 of
holding member form a non-conducting body. The mag
FIG. 8;
net 32 is formed with the north pole on the side surface
FIG. 10 is a top view of the two piece embodiment; and
65 and the south pole on the other side surface 66, and
FIG. 11 is a sectional view taken along lines 11-11
of FIG. 9.
55 magnet 33 is formed with the north pole on the side sur
face 66a and the south pole on the side surface 65a. Thus
Referring to the embodiment shown in FIGS. 1—4,
the inner or facing walls of the magnet are of opposite
the holding or supporting member 10 is a single piece
polarity and the line of magnetic force flow across the
of :molded plastic insulating material. The member is
cavity 13 transverse or normal to the movement of the
symmetrically formed on each side of the vertical plane
parallel to the sides and on each side of the horizontal 60 movable contact 18. The extensive overlap between the
magnets and the cavity ?lls the cavity with lines of force
plane. The member 10' comprises spaced side portions
normal to the side walls.
11 and 12 and an intermediate mounting portion 14
Thus as the movable contact button 27 disengages the
between the side portions and forming a cavity 13 there
?xed contact button 126 while current is being transferred,
with. A bracket 15 is attached to the mounting portion
and supports the holding member 10 to position the 65 any are or spark formed will be ‘generally normal to the
lines of force and the arc is drawn up and out by the
ends of the ?xed contact 17 and the moving contact 18
magnetic ?eld. This drawing or stretching of the arc
in the cavity 13 between the side portions 11 and 12.
The contact 17 comprises a contact button 26 attached
extinguishes it.
The contact buttons ‘are positioned so that 30% or
in a ?xed position to the stationary contact post assembly
16 of the relay by means of the threaded portion 17a and 70 less of each magnet is adjacent to the contacts with the
remaining portion of the magnets positioned away from
nut 17b. The contact 18 is of the resilient ?nger or
bar type mounted on a movable armature of an electro
the contacts in order to draw‘ the are away from the con
3,090,854
4
tacts. As illustrated in FIGS. 4 and 9 the contact buttons
are positioned off from the mid-point of the magnets.
The end wall 22 is located adjacent the middle of the
magnets. Thus in the mounting of the arc quenching de
vice on a contactor or relay, the contact buttons are
preferably off center.
The holding member 19 is positioned by the bracket
15 fastened to the intermediate portion 14. The inter
mediate portion is formed with identical notches 4-2, 413
spaced by a web 44. The web 44 forms a supporting 10
means to fasten the holding member 10 in two positions
to a bracket. The notches have side walls 45, 45a, 46,
and member against which the bracket 15 may bear to
prevent rotation of the holding member on the bolt 61,
complementary blocks 90, 90a extend from a respective
side portion, intermediate portion and barrier.
Holes 97, 97a are provided through the intermediate
members for passing the bolt 61 threaded in the brack
et 15.
It is thus seen from the foregoing description that an
arc quenching device is provided that is formed in either
one or two pieces to form a unitary member to support
permanent magnets providing the quenching flux. The
unitary holding member is easily mounted on the con
tactor or relay by means of a bracket and two threaded
46a and end walls 47, 4% respectiveiy. Since the magnets
are identical and are identically positioned by the side
bolts. Also, the holding member is small with relatively
portions except for the polarity of the sides, the bracket 15 thin side portions to ?t between the pairs of contacts.
may be attached to the holding member either in notch
42 or 43, depending on the desired relation of the polarity
of magnets.
The permanent magnets provide a ?ux that is inde
pendent of the current through the contact. Thus the full
magnetic ?eld is always available independently of the
load current and is effective over a wide range of currents.
The bracket 15 has a generally L-shaped end 49 at
The holding member may be marked with an indicia
tached to the holding member and an L-shaped end 49a 20
such as a plus or minus sign to indicate the polarity of the
attached to the stationary contact post assembly 16. The
magnets. Since the assembly is symmetrical it may be
end 49:: is fastened by a bolt 67 and has a raised portion
63 ?tting in a notch 6%‘ in the frame 16 to position the
mounted to create a force in either of two directions. The
assembly may be mounted in one position when the posi
bracket vertically. The L-shaped end 49' ?ts snugly into
either notch 42, 43 engaging the side walls 45, 45a or 25 tive lead is connected to the stationary contact, or in the
opposite position if the negative lead is connected to the
46, 46a to prevent rotation or movement of the support
stationary contact.
ing member. The web 44 has a hole 60 and a bolt 61
The versatility and adaptability of the device is apparent
passes through the hole and threads into the bracket 15
from the foregoing description. The improvements made
to securely and ?xedly fasten the number 1.0 to the
frame 16.
30 are de?ned in the claims appended hereto.
I claim:
Another embodiment is illustrated in FIGS. 6-11 in
1. An arc quenching device comprising a ?rst molded
which the holding member is formed in two separable
piece having a side panel, a fastening panel extending
and identical pieces 59, 50a. The piece ‘5% is rotated
normal to said side panel, a locking block extending from
180° to interleave with the piece 5% ‘and form a unitary
holding member symmetrical about horizontal and ver 35 said side panel and spaced from said fastening panel, a
second molded piece having a second side panel, a second
tical planes in the same manner as the holding member
fastening panel extending normal to said second side
of the single piece embodiment. There are differences
panel, a second locking block extending from said second
between the single piece embodiment and the two piece
side panel and spaced from said second ‘fastening panel,
embodiment. The holding member 143:: has side portions
51, 51a with recesses '79, 76a for the permanent magnets 40 said ?rst and second fastening panels overlapping to span
the space between said side panels and overlap with a
32, 33. The recesses 79, 76a have side walls 74, 74a and
respective locking block, ?rst and second barrier mem
end walls 75, 75a respectively. The end walls 75‘ and
bers extending between said panels and in opposite direc
75a have grooves 78, 78a for receiving the epoxy resin
tions from a respective fastening panel to de?ne with said
securing the magnets in place. The recesses 76, 70a are
identical to recesses 36, 31 and the magnets are more 45 side panels a contact receiving cavity and form an arc
barrier between supporting means attached to said fasten
or less even with the outer side surfaces.
The cavity 53 is formed by the assembled pieces 50,
59a and the ?xed and ‘movable contacts are positioned
in the same manner as in the embodiment of FIG. 1. The
ing panels and ?rst and second magnets in a respective
side panel overlapping with a substantial portion of said
cavity to provide a flux extending across said cavity to
intermediate portions form overlapping fastening mem 50 extinguish an are created across separating current carry
ing contacts positioned in said cavity.
bers 55, 55a extending from one side portion to the other.
2. A permanent magnet holding member for an arc
The facing surfaces 81, 81a are flat and in ?rm contact
quenching device comprising spaced side portions extend
as illustrated in FlGS. 8 and 9. Barriers 82, 82a extend
ing parallel to one another, an intermediate portion be
along the end adjacent to the cavity 53 to separate the
cavity from the bracket 15 fastened to the intermediate 55 tween said side portions having a web normal to said side
portions.
At the other end raised portions 83, 85a ex
tend between the side portions to recess the exterior sur
portions and narrower than the width of said side portions
to form notches between said side portions on opposite
sides of said web and said intermediate portion ‘having a
faces 84, 84a of the intermediate portions. The two
barrier extending from one side portion to the other and
pieces are laterally and longitudinally interlocked so
that where the two pieces are ?tted together no relative 60 de?ning a cavity with said side portions for receiving
movement can occur between the two pieces except the
separating ‘movement away from one another. Blocks
85, 85a are formed as part of a respective side portion
making and breaking contacts, each of said side portions
having a recess adapted to receive a permanent magnet
and overlapping with a substantial part of said cavity to
create in said cavity a ?ux generally normal to said side
ate portion attached to the same side portion. The inter 65 portions to extinguish an are formed by current carrying
contacts breaking in a movement generally parallel to said
mediate portions of the respective pieces ?t into either
and extend inwardly and are spaced from the intermedi
space 86 or 86a to interlock the two pieces. The barriers
side portions.
3. In combination with an electric contactor having a
82, 82:: also overlap with the blocks 85, 85a. The raised
pair of make and break current carrying contacts, an arc
portions 83, 830 also extend to the side portion of the
other piece and are provided with steps 87, 87a to permit 70 quenching means attached to the contactor by a support
ing bracket, said arc quenching means having two spaced
the overlapping of identical pieces. The surface 88‘ en
side portions and an intermediate portion between said
gages the step 87a and the surface 88a‘ engages the step
side portions, said side portions ‘having inwardly facing
87. Thus the two pieces are interlocked against endwise
movement in either direction.
in order to provide symmetry to the assembled pieces
walls to form with said intermediate portion an open
ended contact receiving cavity and having outwardly
8,090,854
5
facing walls with permanent magnets on opposite sides of
said side portions from said cavity in an overlapping re
lation to provide a flux through said cavity normal to
the relative movement of said contacts for extinguishing
an are formed on separation of said contacts, and sup
porting means located on the other side of said inter
mediate portion from said cavity and between said side
portions, said supporting means having opposite mounting
means for {fastening the arc quenching means in one of
6
6. An arc quenching device for mounting on a relay
having make and break contacts comprising spaced side
portions, a barrier extending from one side portion to the
other side portion intermediate the ends of said side por
tions to ‘form a cavity between said side portions for re
ceiving making and breaking contacts, each of said side
portions having a permanent magnet overlapping with a
substanital part of said cavity to create a flux across said
cavity to extinguish an are formed by current carrying
two positions to relate the ?ux of the magnets with the 10 contacts breaking in a movement transverse to the ?ux,
a web extending generally normal to said barrier and said
polarity on contacts located within said cavity and for
interlocking said supporting bracket and said are quench
side portions and intermediate the edges of said side por
tions to form notches on opposite sides of said web for
mounting the device by single fastening means with the
4. A permanent magnet holding member as set forth in
claim 2 wherein said intermediate portion has means for 15 polarity of the ?ux in the desired relation with the polarity
of the contacts.
attaching said magnet holding member to a bracket in
either of said notches to orientate the ?ux in relation to
References Cited in the ?le of this patent
the polarity of said contacts.
UNITED STATES PATENTS
5. A permanent magnet holding member as set forth in
Wells _______________ __ Apr. 27, 1954
claim 4 wherein the desired relation of the polarity of the 20 12,677,032
Immel et a1. __________ __ vFeb. 24, 1959
2,875,303
contacts and the direction of the ?eld is indicated.
ing means in a non-rotative relation.
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