Note: Descriptions are shown in the official language in which they were submitted.
CA 02902921 2015-09-02
HIGH VOLTAGE SWITCH BLADE CLOSING DETECTOR
TECHNICAL FIELD
[0001] The present invention relates to electric power switchgear and, more
particularly, to a switch blade closing detector for a high voltage electric
power
disconnect switch.
BACKGROUND
[0002] Electric power blade-type disconnect switches utilize elongated
blade
arms to make physical and electrical connections at high voltages, such as sub-
transmission and transmission voltages. The blade arms pivot into and out of
connection with a receptacle typically referred to as the jaws. When the blade
is in the
closed position but not properly engaged within the jaws, the loose connection
generates arcing that can damage the blade and jaws and inject unwanted noise
onto
the electrical system. A variety of techniques have therefore been developed
to ensure
that the blade arm makes a good physical and electrical connection with the
jaws when
the switch is closed. In particular, the blade arm typically rotates as it
comes into
contact with the jaws to form a tight interference fit with leaf springs
within the jaws often
referred to as the fingers. This causes the blade to first enter into the
jaws, and then
rotate so that it is squeezed between the leaf springs of the jaws, to create
an
interference fit ensuring a solid mechanical fit and a good (non-arcing)
electrical
connection between the blade and the jaws.
[0003] The blade and jaws are ordinarily exposed to the elements during
normal
operations. The conventional rotating blade connection works well provided
that the
there is no physical interference between the blade and jaws. During winter
storms,
however, ice can accumulate on the blade and jaws causing the blade to remain
outside
the jaws after the closing action. When the blade is in close proximity but
not fully
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received and rotated into proper engagement within the jaws, the blade is
close enough
for arcing to develop between the blade and jaws. In addition, it may be
difficult for a
technician to visibly detect the poor connection when inspecting the switch
from the
ground, particularly during poor weather. Moreover, power line faults often
occur during
poor weather, making switch operation more likely. The resulting poor
connection may
not be detected until significant damage has been incurred by the switch. An
arcing
contact may also inject current spikes into the power line, which can be
potentially
damaging to sensitive devices, such as computers and other electronic devices.
[0004] Techniques used in prior detectors to indicate a properly engaged
closed
position requires a technician to look at the rotation of a "vertical pipe"
that is part of the
switch linkage, but visually inspecting the linkage is difficult from the
ground, which is a
long distance for viewing. The difficulty is complicated by the fact that
there are a
number of different types of mechanical malfunctions that can occur between
the
linkage and the critical elements of the blade and jaws. Significant
operational
difficulties can occur if there are false indications of proper engagement.
Relying on the
position of the "vertical pipe" in the linkage as the only indication of
proper engagement
of the blade within the jaws has resulted in too many failures of technicians
to detect
improper engagement of the blade within the jaws. Even experienced technicians
can
fail to determine the actual state of blade engagement and the error rate
increases
when with lower level of experience of the technicians.
[0005] As a result, there is significant need for a more reliable and
prominently
visible blade closing detector to prevent false indications of proper blade
engagement
and the resulting damage that can occur from improper blade engagement.
SUMMARY
[0006] The present invention may be embodied in a blade closing detector
for an
electric power switch with an electric indicator, a visual indicator, or a
combination of
electric and visual indicators. A first type of detector uses a gravity switch
and a
magnetic pickup to detect proper engagement between the blade and the switch.
A
second type of detector uses a sliding latch with a visual indicator rod to
provide a visual
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indication of proper engagement of the blade within the jaws. A third type of
detector
uses a magnetic switch with a pivot arm and a dome shaped visual indicator.
These
detectors may be deployed individually or in combination and may be augmented
with
communication equipment to transmit the switch status to a remote location.
Each
embodiment has an indication sensitivity sufficient to distinguish between
proper
engagement of the blade within the jaws and the situation where the blade is
in close
proximity to the jaws but not in proper engagement, for example where
accumulated ice
has prevented the blade from moving into proper engagement.
[0007] Generally described, the blade closing detector is configured for or
installed on a high voltage electric power switch that includes a pivoting
blade arm and
jaws for receiving the blade arm to form a high voltage electrical connection
in which a
proper electrical connection is created by proper physical engagement of the
blade arm
within the jaws. The blade closing detector includes a first detector
component having a
first indicator actuation element carried by the blade arm, and a second
detector
component having a second indicator actuation element located near the jaws.
The first
and second detector components are positioned to cause the first indicator
actuation
element to become positioned adjacent to the second indicator actuation
element when
the blade arm is properly engaged within the jaws. In addition, the first and
second
indicator actuation elements have an indication sensitivity causing an
indicator actuation
to be caused by the first and second indicator actuation elements when the
blade arm
comes into proper physical engagement within the jaws. Similarly, the
indication
sensitivity causes no indicator actuation to be caused by the first and second
indicator
actuation elements when the blade arm comes into close proximity of the jaws
without
entering into proper physical engagement within the jaws.
[0008] The blade closing detector may also include an indicator providing a
visual
distinction between a detector indicator actuation and no detector indicator
actuation.
For example, the visual indicator may include an indicator rod that changes in
position
to provide the visual distinction, such as a "dip stick" moved by a latch
operated during
proper blade engagement. As another alternative, the visual indicator may
change in
color to provide the visual distinction. The blade closing detector may also
include an
electric indicator producing an electric signal providing a distinction
between an
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indicator actuation and no indicator actuation caused by the first and second
indicator
actuation elements and a transmitter for communicating the electric signal to
a location
remote from the blade closing detector. As examples, the remote location may
be a
control panel at the premises where the blade closing detector is located or a
control
center located away from the premises where the blade closing detector is
located.
[0009] There are several alternatives described for the blade closing
detector to
illustrate various approaches for the realizing embodiments of the invention.
In a first
configuration, the first indicator actuation element includes a gravity
activated magnetic
element that moves from an open position when the blade arm is in an open
position to
a closed position when the blade arm is in proper engagement within the jaws.
The
second indicator actuation element includes a magnet that detects the presence
of the
gravity activated conductive element when the blade arm is in proper
engagement
within the jaws. As a specific option, the gravity activated magnetic element
may be a
ferro-magnetic, AINiCo magnetic or other magnetically sensitive ball that
moves within a
tube as the blade is rotated into a horizontal orientation. But the magnetic
pickup has
an indication sensitivity that only detects the presence of the magnetically
sensitive ball
when the blade arm is fully received within the jaws and rotated to
horizontal.
[0010] In another configuration, the first indicator actuation element
includes a
hook and the second indicator actuation element includes a latch configured to
be
moved by the hook as the blade arm moves into proper engagement within the
jaws.
For this option, the visual indicator may be an indicator rod that moves with
the latch to
provide a visual indication of the state of the switch. The hook and latch are
sized and
positioned to exhibit an effective indication sensitivity requiring the blade
arm to be fully
received within the jaws and rotated to horizontal in order for the hook to
physically
engage and move the latch.
[0011] In an third illustrative configuration, the first indicator
actuation element
includes a first magnet and the second indicator actuation element includes a
second
magnet located on a pivot arm that that moves the second magnet from an open
position when the blade arm is in an open position to a closed position when
the blade
arm is in proper engagement within the jaws. For this option, the pivot arm
may be
connected to a linkage that operates an indicator providing a visual
distinction between
'=
an indicator actuation and no indicator actuation caused by the first and
second
indicator actuation elements. But the first and second magnets has an
indication
sensitivity that only move the pivot arm when the blade arm is fully received
within
the jaws and rotated to horizontal.
[0011A] In a broad aspect, the present invention pertains to a blade
dosing
detector for a high voltage electric power switch that includes a pivoting
blade arm
for receiving the blade arm to form a high-voltage electrical connection in
which a
proper electrical connection is created by proper physical engagement of the
blade
arm within the jaws. The blade closing detector comprises a first detector
component having a first indicator actuation element carried by the blade arm,
a
second detector component having a second indicator actuation element located
near the jaws, and the first and second detector components positioned to
cause
the first indicator actuation element to become positioned adjacent to the
second
indicator actuation element when the blade arm is properly engaged with the
jaws.
The first and second indicator actuation elements have an indication
sensitivity
causing an indicator actuation to be caused by the first and second indicator
actuation elements when the blade arm comes into proper physical engagement
with the jaws. The indication sensitivity causes no indication actuation to be
caused
by the first and second indicator actuation elements when the blade arm comes
into close proximity of the jaws without entering into proper physical
engagement
within the jaws.
[0011B] In a further aspect, the present invention a high voltage
electric
power switch comprising a pivoting blade arm, and jaws for receiving the blade
arm
to form a high voltage electrical connection in which a proper electrical
connection
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is created by proper physical engagement of the blade arm within the jaws. A
blade
closing detector comprises a first detector component having a first indicator
actuation element carried by the blade arm, and a second detector component
having a second indicator actuation element located near the jaws, the first
and
second detector components being positioned to cause the first indicator
actuation
element to become positioned adjacent to the second indicator actuation
element
when the blade arm is properly engaged within the jaws. The first and second
indicator actuation elements have an indication sensitivity causing an
indicator
actuation to be caused by the first and second indicator actuation elements
when
the blade arm comes into proper physical engagement within the jaws. The
indication sensitivity causes no indicator actuation to be caused by the first
and
second indicator actuation elements when the blade arm comes into close
proximity of the jaws without entering into proper physical engagement within
the
jaws. Further, an indicator provides a visual distinction between an indicator
actuation and no indication actuation caused by the first and second indicator
actuation elements.
[0011C] In a
still further aspect, the present invention embodies a method for
indicating proper physical engagement of a blade arm within a jaws blade of a
high
voltage electrical power switch in which a proper electrical connection is
created by
the proper physical engagement of the blade arm within the jaws. The method
comprises providing a first detector component having a first indicator
actuation
element on the blade arm, providing a second detector component having a
second
indicator actuation element near the jaws, and positioning the first and
second
detector components positioned to cause the first indicator actuation element
to
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become positioned adjacent to the second indicator actuation element when the
blade arm is properly engaged within the jaws. The first and second indicator
actuation elements have an indication sensitivity causing an indicator
actuation to
be caused by the first and second indicator actuation elements when the blade
arm
comes into proper physical engagement within the jaws. The indication
sensitivity
causes no indicator actuation to be caused by the first and second indicator
actuation elements when the blade arm comes into close proximity of the jaws
without entering into proper physical engagement within the jaws. An indicator
provides a visual distinction between an indicator actuation and no indicator
activation caused by the first and second indicator actuation elements.
[0012] It will be understood that specific embodiments may include a
variety
of features in different combinations, as desired by different users. In view
of the
foregoing, it will be appreciated that the present invention provides a cost
effective
blade closing detector for a high voltage switch. The specific techniques and
structures for implementing particular embodiments of the invention and
accomplishing the associated advantages will become apparent from the
following
detailed description of the embodiments and the appended drawings.
BRIEF DESCRIPTION OF THE FIGURES
[0013] The numerous advantages of the invention may be better
understood with reference to the accompanying figures in which:
[0014] FIG. 1A is a conceptual illustration of a blade-type
disconnect switch
with blade closing detectors in an open position.
[0015] FIG. 1B is a conceptual illustration of the blade-type
disconnect
switch with the blade closing detectors in a closed position.
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,
[0016] FIG. 2A is a conceptual illustration of the blade-type
disconnect
switch with a gravity switch blade closing detector as the blade arm
approaches the
jaws.
[0017] FIG. 2B is a conceptual illustration of the blade-type
disconnect
switch with the gravity switch blade closing detector after the blade arm has
entered into correct engagement with the jaws.
[0018] FIG. 2C is a conceptual illustration of the blade-type
disconnect
switch with the gravity switch blade closing detector where the blade are is
in the
closed position but ice buildup had prevented the blade from entering into
proper
engagement with the jaws.
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CA 02902921 2015-09-02
[0019] FIG. 3 a conceptual illustration of the blade in proper engagement
with the
jaws showing details of the gravity switch blade closing detector.
[0020] FIG. 4A is a conceptual illustration of a blade-type disconnect
switch with
a sliding latch closing detector in an open position.
[0021] FIG. 4B is a conceptual illustration of the blade-type disconnect
switch
with the sliding latch blade closing detector in a closed position.
[0022] FIG. 5 is a conceptual illustration of the blade-type disconnect
switch with
a gravity switch blade closing detector and a sliding latch blade closing
detector.
[0023] FIGS. 6A is a perspective view of a magnetic blade closing detector
in an
open position.
[0024] FIG. 6B is a front view of the magnetic blade closing detector in
the open
position.
[0025] FIG. 6C is a rear view of the magnetic blade closing detector in an
the
open position.
[0026] FIG. 6D is an end view of the magnetic blade closing detector in
the open
position.
[0027] FIGS. 7A is a perspective view of the magnetic blade closing
detector in a
partially closed position.
[0028] FIG. 7B is a front view of the magnetic blade closing detector in
the
partially closed position.
[0029] FIG. 70 is a rear view of the magnetic blade closing detector in the
partially closed position.
[0030] FIGS. 8A is a perspective view of the magnetic blade closing
detector in a
closed position.
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[0031] FIG. 8B is a front view of the magnetic blade closing detector in
the closed
position.
[0032] FIG. 80 is a rear view of the magnetic blade closing detector in
the closed
position.
[0033] FIG. 9 is an assembly view of a detector box of the magnetic blade
closing
detector.
DETAILED DESCRIPTION
[0034] In particular embodiments, a blade-type disconnect switch may
include a
gravity switch blade closing detector, a sliding latch blade closing detector,
or a
magnetic switch with a pivoting arm that operates an indicator. The detector
may
include a visual indicator, and electric indicator, or a combination. The
blade closing
detector is not dependent on the service voltage and, therefore, may be
operated at any
voltage at which a blade-type disconnect switch is operation. It will be
appreciated that
in a blade-type high voltage switch, the blade arm both moves down into the
jaws and
rotates to enter into proper engagement between leaf spring fingers within the
jaws. A
false indication of a proper closing can result if the detector is not capable
of
distinguishing between proper engagement and the situation where the blade arm
is
positioned near the jaws but has not properly engaged within the jaws, which
can result
from ice accumulation, a bent blade arm, a bent or loose blade arm actuator,
an
obstructed blade arm or actuator, or another type of blade closing failure.
The blade
closing detector therefore has an indication sensitivity that distinguishes
between proper
engagement and the situation where the blade arm comes into close proximity of
the
jaws without entering into proper physical engagement within the jaws. As a
result, the
indicator only changes state when the blade arm has moved into its closed
position and
has also rotated into proper engagement within the jaws, and not merely in
response to
the blade arm coming into close proximity of the jaws without entering into
proper
physical engagement within the jaws.
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[0035] The blade closing detectors are typically utilized in high voltage
substations, such as those operating a sub-transmission and transmission
voltages.
The blade-type disconnect switches operate in open air, which exposes them to
weather elements which can include icing, high winds and flying debris.
Although the
switches utilize arcing in open air, they include arcing horns to conduct the
arcing
current before the blade are comes into close proximity to the jaws to protect
the blade
and jaws from damage caused by arcing. Arcing can damage the blade and horn,
however, if the blade arm moves past the arcing horn, comes near the jaws, and
rotates
to the horizontal orientation but without fully entering into the jaws and
engaging into the
desired interference fit between the leaf spring fingers of the jaws. This can
happen, for
example, when ice buildup or a bent or loose component prevents the blade from
fully
entering the jaws at the bottom of the closing stroke before the blade arm
rotates to the
horizontal orientation. Alternatively, the blade arm may fully enter into the
jaws but fail
to properly rotate to the desired horizontal orientation to engage with the
leaf springs
within the jaws. This can happen, for example, when the blade arm actuation
mechanism is loose, broken, bent or obstructed. In both instances, the blade
arm ends
up in close proximity to the jaws without properly engaging within the jaws.
The blade
closing detectors provide an indication when either of these blade closing
failures occur
allowing technicians to take corrective action, such as clearing the switch of
ice or
replacing bent, loose or obstructed components.
[0036] The blade-type disconnect switch may be motorized or operated
manually.
Accordingly, an electric blade closing indication or a visible indication may
be
appropriate depending on the type of switch. It may also be advantageous to
deploy
both types of indicators to provide backup confirmation of proper blade
closing. A
backup gravity switch may also provide an alternate indication in the event
that ice
interferes with operation of the sliding latch indicator. It will be
appreciated that the
specific indicator designs are merely illustrative, and that a variety of
alternatives and
modifications may be employed in accordance with the principles of the
invention. For
example, while two specific types of visual indicators (an indicator rod and a
dome-
shaped color indicator), any suitable type of visual indicator may be
employed, such as
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a pop-up flag, a display surface that flips or rotates, an arm that pivots
from horizontal to
vertical, and so forth.
[0037] FIG. 1A is a conceptual illustration of a blade-type disconnect
switch 10
with a blade closing detectors 20 and 40 in an open position. The disconnect
switch
includes a blade side having a pair of insulators 12 that support a pivoting
blade arm 14.
A receiving side of the switch includes an insulator 16 supporting a jaws 18
that
receives the blade 14 when the blade is pivoted into the closed position, as
shown in
FIG. 1B. This embodiment includes two blade closing detectors, a gravity
switch
detector 20 and a sliding latch detector 40. The gravity switch detector 20 is
described
in greater detail with reference to FIGS. 2A-2C and 3, whereas the sliding
latch detector
40 in greater detail with reference to FIGS. 4A-413. An embodiment including
both types
of detectors is shown in FIG. 5.
[0038] Referring to FIG. 2A and 2B, the jaws 18 includes a pair of fingers
that act
as leaf springs to engage in a tight interference fit with the blade 14.
During the closing
stroke, the blade 14 pivots downward into the space between the fingers with
the blade
arm held at a longitudinal angle. The blade arm then rotates along its
longitudinal axis
to a horizontal orientation causing the blade arm to enter into a tight
interference fit
between the leaf spring fingers within the jaws 18. To provide the blade
closing
detector, the tip of the blade 14 includes a gravity switch 22 serving as a
first indicator
actuation element that is tipped (typically to about 7 declining) into a
gravity activated
position as the blade is rotated into a horizontal orientation for engagement
within the
jaws. Referring to the orientations shown in FIGS. 2A and 2B to illustrate the
operating
principle, the gravity switch is deactivated (moved to the left by the force
of gravity)
when the blade arm is fully rotated counterclockwise, and activated (moved to
the right
by the force of gravity) when the blade arm is fully rotated clockwise to a
horizontal
orientation. A magnetic pickup 24 serving as a second indicator actuation
element is
positioned within or adjacent to the jaws to detect close proximity of the
first indicator
actuation element when the gravity switch has been tipped past horizontal into
a gravity
activated position. The magnetic pickup 24 may be connected to a communication
device 26 operable for transmitting an indication of the status of the
detector 20 to a
CA 02902921 2015-09-02
. .
remote location, which typically includes an electronic indicator located at
the site of the
disconnect switch such as an eye-level control panel in the substation where
the switch
is located, and/or a central control station via SCADA or another suitable
communication system.
[0039] The magnetic pickup 24 has an indication sensitivity
requiring sufficiently
close proximity between the pickup and the gravity switch 22 in the gravity
activated
position to avoid a false blade closing detection upon failure of the blade to
fully enter
the jaws and rotate into proper engagement. That is, the magnetic pickup 24
will not
indicate a proper blade closing when the blade is in close proximity to the
jaws but has
not fully entered into the jaws and rotated into the correct horizontal
orientation within
the jaws. FIG. 2C is a simplified depiction of an incomplete blade closing
stroke, where
ice buildup 28 has prevented the blade 14 from fully entering the jaws 18. In
this
position, the blade 14 is in close proximity to the jaws but has not entered
into proper
engagements within the jaws. As a result, the blade 14 has moved past the
arcing horn
(which extends above the jaws) yet is close enough to the jaws 18 to cause
arcing
between the blade and the jaws. With the blade rotated to horizontal, the
interference fit
between the blade and the jaws typically prevents the blade from dropping into
the jaws
even when the ice melts. With the blade is in this position, it is typically
difficult to
visually detect the improper blade-jaws connection from the ground and any
indicator
triggered by rotation of the blade to horizontal will falsely indicate a
proper blade
closing. Breakers and other protection equipment will also fail to detect this
situation
because the poor blade connection does not produce high fault or neutral
currents. As
a result, the poor blade connection may go undetected for days or longer,
potentially
resulting in arcing damage to the blade and jaws as well as the injection of
arcing noise
into the power line.
[0040] FIG. 3 shows an example type of gravity switch detector 20,
which
includes a tube 22 located on the tip of the blade 14 with a magnetically
sensitive ball
30 serving as the first indicator actuation element located in the tube and
sized to roll
within the tube under the force of gravity. For example, the magnetically
sensitive ball
30 may include ferro-magnetic, AINiCo-magnetic, or another suitable type of
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magnetically sensitive component. The tube 22 is declined with respect to the
horizontal orientation of the blade, for example by 7 as shown in FIG. 3.
This causes
the magnetically sensitive ball to roll from the gravity deactivated position
indicated by
the magnetically sensitive ball 30 to the gravity activated position indicated
by the ball
30' when the blade is rotated into engagement with the jaws. The ball 30 is
likewise
rolled from the gravity activated position indicated by the ball 30' to the
gravity
deactivated position indicated by the ball 30 when the blade is rotated out of
engagement with the jaws.
[0041] Since many disconnect switches are manually operated or inspected,
a
visible indicator may also be utilized. FIG. 4A is a conceptual illustration
of a blade-type
disconnect switch 40 with a sliding latch 44 closing detector in an open
position. In this
embodiment, the underside of the blade carries a hook 42 (serving as the first
indicator
actuation element) that engages the sliding latch 44 (serving as the second
indicator
actuation element) as the blade is rotated into engagement within the jaws.
The sliding
latch 44 extends or is connected to an indicator rod (dip stick) located
within an indicator
tube 45, which may be transparent or have a transparent window or other
indicator
located outside the jaws where it can be easily seen from ground level. The
sliding
latch 44 is spring loaded toward the open switch indication position 46 shown
in FIG.
4A. As the blade rotates into engagement within the jaws, the hook 42 moves
the
sliding latch 44 into the closed switch indication position 48 shown in FIG.
4B. The
indicator may also be connected to a communication device 26, which transmits
the
blade closing status information generated by the sliding latch to a remote
location.
[0042] FIG. 5 is a conceptual illustration of the blade-type disconnect
switch
including a combination of the gravity switch detector 20 and the sliding
latch detector
40 utilizing a common communication device 26.
[0043] FIGS. 6A-6D show perspective, front, rear and end views of a third
type of
detector referred to as a magnetic blade closing detector 60. As with any type
of blade
closing detector, this embodiment may be deployed with or without the
communication
device 26 described previously, as desired. This set of figured shows the
magnetic
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blade closing detector in its open position from different orientations. FIGS.
7A-7C
show the detector in a partially closed position, and FIGS. 8A-8C show the
detector in
the fully closed position. This detector 60 includes a tip bracket 62 that is
carried on the
end of the blade arm 14 and a detector box 64 with a visual indicator 66
mounted to the
switch stand. The tip bracket 62 includes a mounting brace 70 connected to the
end of
the blade arm and magnet support arm 74 that supports a first magnet 76
(serving as
the first indicator actuation element) below the mounting brace 70 where it
will be
brought into close proximity to the detector box 64 when the blade arm 14
moves into
proper engagement within the jaws. The angle between the mounting brace 70 and
the
magnet support arm 74 is adjustable for calibrating the distance between the
magnet 76
and the detector box 64 once they have been installed.
[0044] FIGS. 6A and 6B show the detector box 64 with its plastic cover
removed
to reveal the internal detector mechanism 68, which includes a lever arm 78
that pivots
about a pivot point 86. A first end of the lever arm 78 carries a second
magnet 80
(serving as the second indicator actuation element) and the opposing end
carries a
counterweight 82. The detector box 64 is positioned with the magnet 80
adjacent to the
magnet 76 when the blade arm 14 is in its closed position. The magnet 80 is
slightly
heavier than the counterweight 82 to bias the lever arm to pivot
counterclockwise under
the force of gravity, which allows the magnet 80 to fall downward into its
open position
when the blade arm is in its open position, as shown in FIGS 6A-6D. The
attractive
force between the magnets 79 and 80 is sufficient to overcome the
gravitational bias to
rotate the lever arm 78 clockwise and pull the magnet 80 upward into its
closed position,
which is shown in FIGS. 8A-C.
[0045] As the lever arm 78 pivots between the open and closed positions, it
rotates a connector arm 88 that operates a linkage that, in turn, operates the
dome
shaped visual indicator 66 mounted on the base plate 84 of the detector box
64. In this
particular embodiment, the visual indicator includes an outer dome divided
into a
number of colored sections 90A-90N (typically black) and a number of
transparent
sections 92A-92N. An inner dome carries corresponding first colored sections
91A-91N
having the same color as the colored sections 90A-90N or the outer dome
(typically
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, .
black), and alternating second colored sections 93A-93N that have a different
color
(typically red). When the detector is in the open position, as shown in FIGS.
6A-6D the
first colored sections 91A-91N of the inner dome are positioned under the
transparent
sections 92A-92N of the outer dome so that the indicator 66 appears to have a
solid
color (typically black). When the detector is in the closed position, as shown
in FIGS.
8A-8C the second colored sections 93A-93N of the inner dome are positioned
under the
transparent sections 92A-92N of the outer dome so that the indicator 66
appears to
have sections with alternating colors (typically red and black).
[0046] FIG. 9 is an assembly view of the detector box 64 the
internal components
of the detector box including the linkage 94 that operates the visual
indicator. The
indicator includes an outer dome 95 (having alternating colored sections 90A-
90N and
transparent sections 92A-92N) and an inner dome 97 (having alternating first
colored
sections 91A-91N and second colored sections 93A-93N). The connector arm 88
operates a linkage 94 under the domes that rotate the inner dome 97 so that
the first
sections of the inner dome are positioned under the transparent sections of
the outer
dome to give the indicator a first appearance to indicate a first switch state
(e.g., solid
color indicating an open switch, as shown in FIGS. 6A-6D). Similarly, when the
blade
arm is properly engaged in the jaws, the connector arm 88 operates a linkage
94 to
rotate the inner dome 97 so that the second sections of the inner dome are
positioned
under the transparent sections of the outer dome to give the indicator a
second
appearance to indicate a first switch state (e.g., alternating colors
indicating a closed
switch, as shown in FIGS. 8A-8C).
[0047] In view of the foregoing, it will be appreciated that
present invention
provides significant improvements in blade closing detectors for high voltage
switches.
The foregoing relates only to the exemplary embodiments of the present
invention, and
that numerous changes may be made therein without departing from the spirit
and
scope of the invention as defined by the following claims.
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