United States Patent 1191
1 1111
Norman et a1.
[73]
[22]
[21]
TRANSFORMERS WITH POLYPHASE
SLIDING CONTACT ASSEMBLY
Inventors: Sivert Norman; Jan Syren, Uno
Zetterlund, all of Ludvika, Sweden
Assignee: Allmanna Svenska Elektriska
Aktiebolaget, Vasteras, Sweden
Filed:
June 5, 1973
Appl. No.: 367,098
2,717,296
9/1955
Foley et al ................ .. 200/11 B UX
3,045,090
3,192,328
3,639,706
‘3,673,364
7/1962
6/1965
2/1972
6/1972
Wilson, Jr. et al. ......... .. 200/11 B
Wilson, Jr. ...................... .. 200/11
Purdy .......................... .. 200/16 F
Klein ........................... .. 200/16 F
Foreign Application Priority Data
June 27, 1972
Sweden ............................. ., 8402/72
X
B
X
X
FOREIGN PATENTS OR APPLICATIONS
950,794 10/1956 Germany
139,352v 3/1953 Sweden
Primary Examiner-James R. Scott
[57]
[30]
3,824,355
145] July 16, 1974
154] DE-ENERGIZED TAP CHANGER FOR
[75]
_
’
ABSTRACT
A tie-energized tap changer for transformers com
prises avframe of insulating material, a‘ slide which car
ries movable contacts, the slide being displaceable in
[52]
us. (:1 ............ .. 200/16 F, 200/17 11,200/16 c
the frame, and a drive for the slide. The frame of the
[51]
[58]
1111.01. ......................................... ..u0111 15/06
Field 61 Search ......... .. 200/11 B, 11 TW, 16 B,
tap changer is manufactured in one piece and consists
200/16 E, 16 F, 17 R, 11 TC, 18,156, 162,
163, 16 c, 16 D
[56]
References Cited
UNITED STATES PATENTS
2,502,438
2,577,955
4/1950
12/1951
Deakin ._ ...................
200/16 F X
Dixon .......................... .. 200/16 F X
of a terminal "bar with attachment means for connec
tions from the transformer windings, a carrier member
carrying the drive, and cross-bars connecting the ter
minal bar and the carrier member. The movable slide
is displaceable in grooves in the cross-bars and can be
inserted in the grooves only when situated outside its
ordinary working area.
7 Claims, 4 Drawing Figures
3,824,355
PATENTEDJUL 1 6 I974
sum '1 (IF 2
3,824,355 A f
1
2
DE-ENERGIZED TAP CHANGER FOR
bar '2 are connected to each other by means of two
TRANSFORMERS WITH POLYPHASE SLIDING
CONTACT ASSEMBLY
cross-bars 6.
‘
When the frame is manufactured a number of tubes
7 of brass or the like are cast into the terminal bar. The
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to de-energized tap changers
tubes project slightly from one side of the terminal bar.
The pins 3 applied by contact pressure, for example, to
the conductors 4 are constructed so that their free ends
can be inserted in the tubes 7 and said pin ends are so
for transformers.
2. The Prior Art
'
long that they protrude from the tube when the pins are
There are a number of prior art de-energized tap
‘fully inserted, as can be seen in FIG. 1, thus forming the
stationary contacts of the tap changer. Each pin has a
changers, but these are rather complicated and the
conversion of them from linear to zig-zag connection of
the control winding is complicated.
peripheral groove 8 and, when the pin is fully inserted
~
in the tube, the sleeve is pressed into the groove so that
the pin and sleeve are joined together and the pin is se
SUMMARY OF THE INVENTION
curely anchored in the frame.
In a preferred embodiment of the invention the pins
The present inventionrelates' to a de-energized tap
changer for transformers and comprises a frame of in- I
are made of aluminium. This is particularly suitable if
the transformer winding is also of aluminium since
sulating material, a slide having movable contacts, said
contact pressure between conductor and pin then per
slide being displaceable in the frame, and drive means mits a reliable connection to be achieved very quickly.
for the slide. According to the invention the frame,
The pin 3 is designed partially in the form of a socket
manufactured in one piece, comprises a terminal bar
into which the transformer-conductor 4 is inserted and
with attachment means for connections from the trans
‘the socket is pressed around the conductor in known
former windings, a carrier member supported by cross
manner. The free end of the pin, which projects out of
bars from the drive means and grooves arranged in the
25 the tube is silver-plated in order to give the best possi
cross-bars for the movable slide.
_
.
ble current-transmitting properties between the pin and
Because the frame is manufactured in one piece and
the movable contact.
_
constructed as described hereinafter, the job of assem
bling the de-energized tap changer is considerably sim
plified in comparison with the types of tap changers
now in use. Furthermore, the tap changer can be modi~
fied so that it can be used both for linear and zig-zag
connection ofthe control winding and for Y or D con
nection of the transformer.
The slide 9 is displaceable in the two cross-bars 6 and
has three movable contacts 10, one for each phase. The
30 construction of the contacts can be seen best in FIG. 3
which is a section along the line III—III in FIG. 1. Each
contact is attached in the slide with the help of two lugs
, 11 which may be moulded in one piece with the slide
or attached to theslide in some known manner. The
'
Essentially, ‘the tap changer includes a frame of insu 35
contact consists of two parallel-trapezoidal contact
piecesl2,
kept in place between the lugs with the help
ber forming parts of the frame, the cross-bars support
of
two
guide
pins 13 passing through the contact pieces
ing the carrier member at a distance from the terminal‘
and nonrotatably mounted in the lugs. The contact
bar. A slide with contacts thereon is displaceably
lating material which has cross-bars and a carrier mem
pieces are kept at the correct distance from each other
mounted in the frame for engagement with connections
from the transformer windings. The contacts on the
slide have contact surfaces, one contact surface being
of a length less than the distance between two adjacent
stationary contacts while the other contact surface is at
by a spacer l4 and pressed against this spacer by two
compression springs 15 which abut the contact piece
with-one end and are arranged in a groove 16 on each
of the. lugs 11 at the other end. Each contact piece has
turned upside down for zig-zag connection.
cinity of the shorter of thetwo parallel edges of the
least as long as a distance between two stationary 45 on one ?at surface two raised contact surfaces 17 and
18, respectively, one of which, 17, is located in the vi
contacts. The contacts‘mounted on the slide can be‘
contact piece while the other contact surface, 18, is lo- _
cated in the vicinity of the long, parallel edge of the
piece. FIG. I shows that the short contact surface is in
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings FIG. I shows the de
contact with one of the contact pins 3. The length of
the short contact surface should be less than the free
distance between two adjacent stationary contacts so
energized tap changer assembled for linear connection
and with connection means for only one phase. FIG. 2
shows a side view of the slide. FIG. 3 is a section along
the line lll-Ill in FIG. I and shows a ‘cross-section
that it can never connect two such contacts together.
The length of the contact surface 18 should be at least
55
through a movable contact on the slide. FIG. 4 is a sec I as long as the distance between the centers of two adja
tion along the line IV—-IV in FIG. I to show how the
slide is fitted in a cross-bar.
,
cent stationary contacts so that it can connect two adjaé
'
cent stationary contacts together.
When the contact piece 12 is in the position shown
DESCRIPTION OF THE PREFERRED
EMBODIMENTS
'
The frame I of the de-energized tap changer is made
of insulating material and compression-moulded in one
piece. It comprises a terminal bar 2 supporting pins 3
which are connected to conductors 4 from the trans
former windings. The Figure shows only‘pins for a sin
gle phase. The frame also comprises a carrier member
5 for the drive means. The carrier arm and the terminal
60
in FIGS. 1 and 3, the fourth stationary contact from the
right is joined to a busbar 19 which in turn is connected
to a terminal pin 20 furthest to the left in the group of
contact pins in the terminal bar. The short contact sur
face I7 is then in contact with the stationary contact
and the long contact surface 18 is in contact with the
busbar 19. The three terminal pins 20, one for each
phase, are connected in known manner to earth or to
a zero point. How this is done is immaterial for an un
3
3,824,355.
1
derstanding of the invention. The busbar 19, one for
each phase, is attached by one end to the‘ terminal pin
20 and by the other end to the frame. ln'FIG. l the bar
is assumed to be a tub, its righthand end being pushed
over a pin 21. For the lefthand and center bar, the pins
are placed on the cross-pieces 6 whereas the support
4
The de-energized tap changer is assembled as fol
lows:
‘
Theslide, together with its three movable contacts,
is placed over the grooves in the frame with the reces
ses 25 above the guide-bosses 24. In this position the
slide can be placed in the grooves. The slide is then
moved tov one side, to the right in the embodiment
pin for the ,righthand bar is on a lug 22 on the frame.
shown in FIG. 1, so that the recesses 29 are opposite
the position of the toothed wheel. The toothed wheel
is then positioned with its teeth engaging the recesses.
According to the embodiment of the invention shown
in FIG. 1, the de-energized tap changer is assembled for
The shaft 27 which transfers the driving movement to
linear connection, but it can easily be converted for use
with zig-zag connections. In such a connection the ,5 the toothed wheel is inserted and locked in position so
that the toothed wheel cannot be moved from its plane.
transformer control winding is divided into two parts
and the connections from the two parts are connected
We claim:
alternately to the pins 3. Two adjacent pins or station
'
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l. De-energized tap changer for transformers, com
ary contacts are then permanently connected together
prising a frame of insulating material, a slide having one
by the movable contact 10. With this connection no
movable contact for each phase, means mounting said
busbar is necessary and the terminal pin 20 may be re
slide displaceably in the frame, and drive means'for the
placed by a pin 3 if necessary. In order to be able to
slide,'in which the frame (1) is manufactured in one
connect two stationary contacts, the two contact pieces 20 piece and comprises a terminal bar (2) with stationary
12 are turned upside down so that the long contact sur
. contacts thereon for connection with the transformer
face 18 abuts the stationary contacts. The short contact _
‘windings and engageable by said movable contacts,
surfaces then have no function-to ful?l.
4 said mounting means comprising cross-bars (6) form
In order to allow reversal of the positions of the
ing a part of the frame and extending transversely to
contacts 12, they may for example be provided with
square central holes ‘which engage the squared central
25
the direction of movement of the slide and having
grooves (23) therein for mounting the movable slide
portion of the pin 13 which is fixed in the lugs 11. How
(9), and a carrier member forming a part of the frame
and supported by the cross-bars at a distance from the
ever, the pin 13 adjacent the outermost positions of the
terminal bar and supporting the drive means for the
contact piecesl2 is round in cross-section, so that by
outward movement of the contact pieces they can be 30 slide.‘
2. De~energized tap changer according to claim 1, in
reversed or turned upside down.
The slide 9 is displaceably journalled in grooves 23
which each cross-bar (6) is'provided with a guide boss
' (24) projecting slightly over the groove (23) for the
24 which protrudes slightly across the groove. This can ' slide and the slide is provided with-recesses (25) corre
be seen best in FIG. 4. The slide is thus normally locked 35 sponding'to the guide bosses so that the slide can be
placed in the groove when the recesses are opposite the
in the grooves. So that the slide can be put in position
guide
bosses and that, after longitudinal displacement,
in the grooves, it is provided with two recesses 25, the
it is held in the groove by the guide bosses.
distance between these being equal to the distance be
3. De-energized tap changer according to claim 1, in
tween the guide bosses 24. When the slide is placed
which
the drive means for the slide (9) comprises a
40
over the grooves 23 with the recesses 25 opposite the
toothed wheel (26) journalled in the carrier member
guide bosses24, the slide can be moved into place in
'(5), said slide having recesses (29) therein, said wheel
the groove, but as soon as the slide is then moved in one
engaging in said recesses.
in the two cross-bars 6. Each cross-bar has a guide boss
direction or the other, itv becomes locked in position by
the bosses. The recesses 25 are so positioned that they
cannot be located opposite a guide boss during the nor
'mal operating movements of the tap changer. The
guide boss 24 may be at the side of the groove as shown
in FIG. 1 orit maybe placed differently, for example
above the groove.
‘
4. De-energized tap changer according to claim 3, in
i which the recesses (29) in the slide corresponding to
the teeth in the'toothed wheel (26) terminate at a dis
tance from both side surfaces of the slide.
5. De-energized tap changer according to claim 1, in
which the slide is provided with three pairs of lugs ( 1‘1) '
which carry the movable contacts (10).
The movement of the slide is effected with the help 50 6. De-energized tap changer according to claim 1, in I
which the movable contacts (10) are composed of-two
ofa toothed wheel 26. The, wheel is driven with the
similar contact plates ( 12) having the shape of a paral
help of some known device, not shown here. The
lel-trapezium, with contact surfaces (17,18) at the par
toothed wheel is non-rotatably joined to a shaft 27
allel edges, one contact surface (17) being shorter than
passing through a lug 28 at one end of the carrier mem
ber 5. The carrier arm is preferably provided with a 55 the free distance between adjacent stationary contacts
(3) on the terminal plate while the other contact sur
journalling lug at each end‘ so that the toothed wheel
face (18) is at least as long as the distance between the
can be positioned either to the right or the left depend
centers of two adjacent stationary contacts.
I
ing on the position of the tap changer in the trans
7. A de-energized tap changer according to claim 1,
former.
The toothed wheel cooperates with recesses 29 on 60 in which the frame is provided with a bus bar (19) for
each phase arranged parallel with and at a distance
the side of the slide facing the toothed wheel. As can
from the terminal bar, and said movable contacts (10)
be seen from FIG. 2, the recesses 29 terminate a little
way from the upper and lower surfaces of the slide.
This means that when the slide is in position in its
on the slide are reversible and assymme'trical, each
contact in each ' of its positions effecting electrical
65 contact between a single stationary contact and said
grooves 23 and the toothed wheel is placed with its - bus bar and in another position effecting connection
teeth in the recesses of the slide; the wheel cannot be
between adjacent stationary contacts.
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moved in the direction of the axis of shaft 27.