ABB ACQ580-34 - When to Disconnect EMC Filter and Ground-To-Phase Varistor: TN-S, IT, Corner-Grounded Delta, and Midpoint-Grounded Delta Systems; Guidelines for Installing the Drive to a TT System

￭ When to disconnect EMC filter and ground-to-phase varistor: TN-S,
IT, corner-grounded delta, and midpoint-grounded delta systems
Symmetrically grounded TN systems (TN-S systems)
Do not disconnect EMC AC and VAR wires.
PE
L2
L3
L1
N
Corner-grounded delta systems
Do not install the drive on a corner-grounded system.
PE
L3
L2
L1
Midpoint-grounded delta systems
Do not install the drive on a midpoint grounded system.
PE
L3
L2
L1
IT systems (ungrounded or high-resistance grounded [>30 ohms])
Disconnect EMC AC and VAR wires.
L3
L2
L1
￭ Guidelines for installing the drive to a TT system
The drive can be connected to a TT system under these conditions:
98 Electrical installation