Note: Descriptions are shown in the official language in which they were submitted.
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This :Lnventlon relates general~y to air core reactors ~or
use inindustrialor utility power systems and more particularly, to
improvements ln a tapped air core reactor.
The present applicant has over the years developed and
~rketed in many countries throughout the world, air core reactors
consisting essentially of rigid cylindrical coil onits disposed in spaced
apart concentric relation and having a spider unit at each of opposite
ends thereof serving as line terminals for connecting to the power lines
and means to connect the coils in parallel. Applicant's earlier develop-
ment of such type reactor is disclosed in Canadian Patent 756~250 issued
April 4th, 1967. Further developments are disclosed in applicant~s
Canadian Patent 965,166 issued March 25th, 1975 and ln pending Canadian
application 27~,630 ~iled 2Iarch 23rd, 1977. In the latter application
there is disclosed a tapped air core reactor constructed in such a manner
as to permit the reactors to be stacked one on top of the other when
used in a three-phase system. The tapping coil is a pancake type coil
mounted on one of the end spiders. The draw-back, however, with such
arrangement is that when the reactors are stacked one on top of the
other the tapping terrninals are located between the reactor units.
A principal object of the present invention is to provide
a structurally rigid, tapped reactor with the tapping terminals located
such as to Eacilitate making connections thereto.
Another principal object of the present invention is to
~; ; provide a tapped changing method designed to maintain the input and output
terminals at a Eixed location such that permanent three-phase bus work
nstallation is feas1b1e.
- A further priDcipal object of the present invention is to
` provide~a tapped alr core reactor wherein changing from one tap to another
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may be eEfected with~-lL di~co~necti~g the ~Ain ter~inals utllized ln
connecting the reactor to the power system.
In keeping wlth the foregoing, there is provide~ in accord-
ance with the present invention a tapped air coil reactcr comprising
two or more open ended cylindrical rigid coil units disposed in concentric
spaced apart relation, a structurally rigid, electrical conducting, spider
unit at each of opposite ends of said coils, electrical insulating means
interconnecting said spider units to provide a structurally rigid reactor
unit, all of said coil units, except the radial outermost one thereof,
10 having coil windings connected at each of opposite ends to the respective
spiders, said radial outermost coil having a winding extending axially
along only a portion of the length of the other coils and the remaining
length being constituted by a cylindrical insulating sleeve, said radial
outermost coil having a plurality of tap terminals secured to the coil winding
thereof and located at various different peripheral positions and adjust-
able means for connecting any one of the tap terminals to one of said
spider units.
The invention is illustrated by way of example with reference
to the accompanying drawings wherein:
Figure 1 is an elevational view of three identical single
phase reactors provided in accordance with the present invention stacked
vertically in coaxial juxtaposed relation;
Flgure 2 is essentially a top plan view of Figure l;
Figure 3 is a cross-sectional view taken along section 3-3
of Figure 2;
Figure 4 is similar to Figure 3 but illustrating minor
modifications thereto;
Figure S is a partial, enlarged sectional, view of a portion
of the tapping coil :Lllustrating one of the tap terminals;
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Figure 6 is a leEt-hand s~de eLevational view of ~igure 5; and
Figure 7 is a sche~atic circuit dia~rarl for the alr core
reactor provided in accordance with the present invention;
Referring to the drawings, there is lllustrated in Flgure 1
three tapped reactDrs 10 stacked vertica:Lly one on top of the other in
coaxial relation for connecting to a three-phase electrical system by
terminals A and B of the respective unit~;. Terminal A the input, and
terminal B the output, are in fixed locations on the respective units
permitting permanent three-phase bus work installations.
Each reactor un:it designated generally by the reference
numeral 10 consists of a plurality of open endedcylindrical coil units l:L,
12, 13 and 14 disposed in spaced a~art concentric relation and located
between a pair of end spiders 15 and l6. Eac'n of the end spiders is a
rigid electrically conducting unit consisting of a central hub 17 having
a plurality of arms 1~ radiating outwardly therefrom. The end spiders
15 and 16 are interconnected by a plurality of tie members 19 tensioned
to hold the spider units tight against opposed ends of the cylindrical
coils. The tie members 19 are made of an insulating material or at least
are insulated from the spiders in such a manner as to prevent short circuiting
from one spider to the other 'oy way of the tie means.
Each reactor unit has a plurality of pedastal and insulator
units 20 attached to the lowermost spider thereof for mounting one reactor
unit on top of the other and supporting the lowermost reactor unit on
a suitable foundation.
The inner cyllndrical coilunits 11, 12 and 13 constitute
a main coil section 25 (see Figure 7) of each reactor unit and the
outermost coil 14 constitutes a tapping coil section. Each coil unit ll,
12 and 13 of the main coil section consists of one or more conductors
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26 helically wound aroun~ the axis of the cylinder and embedded in a
resinous materi.al 27 rein~o~ce~, pre;ferably, witl~ fllament glass to provide
a rigid assembly wllen cured. Each coil ~Init 11, 12 and 13 is thus an
independent, rigid cy]indrical unit. TIIe conductor 26 of the respective
coils 11, 12 and 13 is connected at one end to spider 16 and at the other
end to spider 15 electrically connecting the coils in parallel. As
disclosed in applicant's previous applications, the spider arms permit
connecting the coils in fractional turns to balance the coils preventing
circulating currents and avoiding the necessity of transposed windin~s
as required in earlier current limiting reactors.
The outermost cylindrical coil 14 constitutes a tapping coil
section having a plurality of tap terminals 30 to 3~ located at different
positions circumEerentially around the coil. The tap terminals 30 to 36 are
also located at various spacings from the bottom spider 15; tap terminal 30
being closest thereto and tap terminal 36 being furthest thereErom. Any
number of tap terminals may be provided dependent upon the customer needs.
Each tap terminal is a heavy metal plate welded or otherwise
permanently attached to the conductor of coil 14 and has apertures 37 for
receiving bolt and nut UIIitS 38. Any one of the tap terminals may be con-
nected to the bottom spider 15 by a tap changer bar unit designated generally
by the reference numeral 40. The tap changer bar unit consists of a first
angle member 41, apertured to receive bolt and nut units 38 to connect the
same to a tap terminal, and a second bar member 42. Bar members 41 and 42
are interconnected by bolt and nut units 43 slidable in slots 44 in the
bar 42. The length of the slots 44 is such as to permit connecting to
any one of the tap terminals wbich are variously spaced from the spider 15.
The other end of bar member 42 is connected to a plate 45 on the outer end
of an arm of the bottom spider 15. ~or this purpose the arms of the botto~
spider extend radially beyond the outermost coil unit 14 and each has an
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aperturecl p:Late 45 secu~ed ~ reto. The bar 42 ls connected to the bracket
members 45 by bo:Lt and IlUt unit~ 46,
From ~he foregoing arrange~e~t, ~t wil~ be readily apparent
the tap changer 40 may be readily adjusted so as to be connectible
to any one of the tap terminals~ even though located at differen~ spacings
from the bottom spider.
The outermost coil 14, i.e. the tapped coil section of the
reactor, is an open-ended cylindrical unit having a conductor 50 wound
to extend axially along only a portion of the length of the reactor, this
axial length being designated ~ in Figure 3, and the remainder of the length
(designated ~ in Figure 3) is a cylindrical spacer of insulating material
having the same diameter as the wound coil. The conductor 50 may be a solid
rod or cable conductor wound into an open helix or multiple conductors
wound simultaneously. The outermost coil 1~ is preferably made by winding
the conductor 50 onto a winding mandrel and filling the spaces between
adjacent helices with a glass fibre reinforced settable plastics material.
Before the resinous material completely fills the space between adjacent
helices the terminal bars are welded to the conductor and thereafter the
filament glass and resin is wound continuously on the mandrel filling the
remaining space between the adjacent helices and builds up radially outwardly
therebeyond to form a rigid cylinder unit. In Figure 5 the cylindrical
coil 14 has inner and outer peripheral surfaces designated 51 and 52 with
the conductor 50 substantially encapsulated therein, except for perhaps
a minor portion of the conductor which is in contact with the winding
mandrel during forming of the cylinder~
The conductor 50 normally is not connected to the
bottom spider and thus tapping effectively shorts out unwanted turns
of the tapping coil section to the bottom spider. The
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utilized number of tu~ns fPr tlle tapped sectlon is counted from the top
of the winding downwarcl as vlewed in, ~r e~a~ple, Figure 3, and tlle highest
tap terminal on tile tapped coLl sectLon serves as the output terminal
designated B on the drawings. If desirecl for single or three-phase mounting,
the tap winding can be connected to the bottom spider. In such case no
tap changer will be used and tapping is done by bus connection made
directly to a specific tap and the number of utili~ecl turns will be counted
from the bottom of the section upwardly.
From the foregoing it will be seen the cylindrical coils
are concentrically disposed and spaced apart from one another and tlle
spiders at opposite ends interconnected by ties provide a rigid, robust
unit.
Figure 4 illustrates minor alternatives which include arms
on the upper and lower spiders stepped Erom the remaining portion of the
spider arms so that effectively the outermost coil 14, i.e. the tapping
coil section, has an axial length greater than the axial length of the
main coils. Stepping of the spider arms may be done in any one of a number
of different ways, the simplest being joining additional sections(designated
65) tothe respective spider arms. The additional section on the spider arm
may be used on each of the top or bottom spiders or, alternatively, either one
or the other. The purpose of the stepped arm spider is to create extra arcing
distance between the input terminal and the highest tap terminal for
high voltage coils. In Figure 4 there is also illustrated a dummy package
designated 70 which is an insulated cylindrical sleeve of required thickness
to act as a voltage barrier to prevent arcing between the corner of the main
coil part of the spiders to the tap section winding.
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