ABB UniGear ZS1 - Page 108

108
NALF switch-disconnectors
The NALF switch-disconnectors, combining a
switch-disconnector with fuses and earthing
switches are intended for indoor use in
switchboards. The switch-disconnectors can
open and close loaded and unloaded inductive
and capacitive circuits. In the open position the
device has a visible isolating distance.
The switch-disconnectors are used in
combination with power fuses as short-circuit
protection. This combination excludes two-phase
power supply, because the interruption of any
fuse link causes the opening of the switch-
disconnector by its tripping system.
The earthing switches are constructed with a
snap closing mechanism. They can close and carry
short-circuit currents.
Operating mechanism of the switch-disconnector
for use in UniGear switchgear:
Operating mechanism – with two springs.
The opening spring is always charged before the
closing of the switch-disconnector. This means,
that the closed switch-disconnector always has
stored energy in the opening spring and the
opening follows immediately with the manual
lever, opening shunt release or fuse tripping
mechanism. This mechanism facilitates remote
opening and in combination with the motor
operating mechanism makes completely remote
control possible.
The earthing switch is always operated locally by
the operating lever 1 (Figure 180).
To secure the protection of connected MV
equipment the UniGear switchgear with switch-
disconnector uses CEF medium voltage fuses.
The UniGear switchgear with NALF switch-
disconnector can be equipped with a range of
fuses according to the following table.
In cases that the switch-disconnector without MV
fuses will be required, the current-carrying bars
will be inserted in holders instead of the MV fuses
to maintain the same location of the earthing
switch.
Notice:
The switch-disconnector and earthing switch can
only be operated with the switchgear panel door
closed. The switch-disconnector and earthing
switch are mutually mechanically interlocked.
—
7. Operation of the switchgear
Un [kV]
In min. [A] In max. [A]
7.2
6 200
12 6 125
17.5 6 160
24 6 125
Range of fuses
Figure 179:
1 Lockable operating handle – padlock
2 Position indicator of earthing switch
3 Operating shaft for the earthing switch
Figure 180:
1 Operating lever
Preparation for the operation of
earthing switch in panel with the switch-disconnector
operating lever prepared for the ON operation
Preparation for the operation of
earthing switch in panel with the switch-disconnector
operating lever prepared for the OFF operation