ABB ACH580-01 - Ground-To-Phase Varistors; When to Disconnect EMC Filter or Ground-To-Phase Varistor: TN-S, IT, Corner-Grounded Delta and Midpoint-Grounded Delta Systems

filter. See sections When to disconnect EMC filter or ground-to-phase varistor: TN-S,
IT, corner-grounded delta and midpoint-grounded delta systems (page 116), and
Guidelines for installing the drive to a TT system (page 117).
WARNING!
Do not install the drive with the EMC filter connected to a system that the filter is
not suitable for. This can cause danger, or damage the drive.
Note: When the internal EMC filter is disconnected, the drive EMC compatibility is
considerably reduced. See EMC compatibility and motor cable length (page 290).
￭ Ground-to-phase varistors
A drive with the ground-to-phase varistor connected can be installed to a symmetrically
grounded TN-S system. If you install the drive to another system, you may need to
disconnect the varistor. See sections When to disconnect EMC filter or ground-to-phase
varistor: TN-S, IT, corner-grounded delta and midpoint-grounded delta
systems (page 116), and Guidelines for installing the drive to a TT system (page 117).
WARNING!
Do not install the drive with the ground-to-phase varistor connected to a system
that the varistor is not suitable for. If you do, the varistor circuit can be damaged.
￭ When to disconnect EMC filter or ground-to-phase varistor: TN-S, IT,
corner-grounded delta and midpoint-grounded delta systems
Requirements for disconnecting EMC filter and varistor and additional requirements for
different electrical power systems are given below.
IT systems (ungrounded or
high-resistance grounded
[>30 ohms]) (C)
Corner-grounded (B1) and
midpoint-grounded delta
systems (B2)
≤ 600 V
Symmetrically groun-
ded TN systems (TN-S
systems) ie. center-
grounded wye (A)
Frame
size
Disconnect EMC and VAR
screws.
Disconnect EMC screw.
Do not disconnect VAR
screw.
Do not disconnect EMC
or VAR screws.
R1…R3
R4 v2
Disconnect EMC screws (2
pcs) and VAR screw.
Not evaluated
1)
Do not disconnect EMC
or VAR screws.
R4…R5
Disconnect EMC screws (2
pcs) and VAR screw.
Do not disconnect EMC AC
or VAR screws.
Do not disconnect EMC
or VAR screws.
R6…R9
Disconnect EMC DC screw.
116 Electrical installation – IEC