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16
G R I D S H I E L D
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5 Operation
All GridShield
phase and single-phase trip and close operations.
You can achieve electrical opening and closing
using the associated control. For single-tank units
(3P), you can achieve mechanical opening by pulling
down the yellow trip handle. For 3SP units, you
need to pull down three separate yellow handles,
one per pole, to achieve mechanical opening.
5.1 Closing
When in the open position, the armature is
positioned against a spacer in the actuator
assembly. It remains there due to the force exerted
by the opening spring and a small force generated
by the magnet. When the coil is energized correctly,
it produces a magnetic flux in the same direction
as the magnet assembly. This magnetic force pulls
the armature into the coil, causing it to make
contact with the upper pole piece.
Once the armature is in contact with the upper pole
piece, the coil is no longer energized, and the
magnet alone holds the armature in place. As the
armature is drawn into the coil, the operating rod,
which is connected to the adjustment rod, moves
the moving contact of the vacuum interrupter to
the closed position.
It's worth noting that the actuator has a greater
range of movement than the vacuum interrupter.
Therefore, the interrupter contacts make contact
before the actuator completes its full stroke.
The additional movement of the operating rod
after the contact closes is necessary to allow the
contact pressure spring to compress at the top
of the operating rod. This extra travel, also known
as contact wipe, accounts for contact wear during
operation and helps maintain low contact
resistance.
®
3 P/ 3 S P R E C L O S E R
reclosers can perform both three-
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5.2 Opening
When the coil is energized with the opposite
polarity, the magnetic flux it produces counteracts
the force generated by the magnet assembly.
As a result, the holding force decreases, and the
armature is released. Subsequently, the opening
spring, with some initial assistance from the
contact pressure spring, propels the operating
rod to the open position.
5.3 Mechanical opening
If the electrical system becomes disabled or
de-energized, the upper recloser unit can be safely
opened using a mechanical method. To manually
open it, simply pull down quickly and firmly on the
yellow trip lever located on the side of the HV unit.
This action will mechanically open all three poles
at the same time.
In the case of a 32-/42-pin single-tank recloser unit,
the yellow trip handle should be turned a full 90
degrees from a horizontal to a vertical position.
This position provides a clear and visible
indication. The recloser unit includes a standard
feature called block close (69 function), which
prevents a local or remote close. The 69 switch
is connected to a relay input and programmed
to block the closing operation. For single-tank
reclosers, the yellow handle mechanically prevents
the closing operation until it is reset.
In 3SP units, each pole has its own individual yellow
trip handle. The handle should be turned at 45
degrees from the horizontal position to activate
the block close (69 function). To perform a manual
mechanical 3-phase open, you need to pull down
each trip handle individually. Alternatively, you can
program the relay to simultaneously open all poles
when any one of the yellow handles is pulled down.
An optional CLOSE BLOCK feature can be added
to enable manual trips.
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