ACS550-02/U2 User’s Manual 45
Installation
Disconnecting the varistor on IT (ungrounded) and corner grounded TN systems (frame
size R7)
WARNING! If a drive with its varistor connected is installed on an IT system [an
ungrounded power system or a high resistance-grounded (over 30 ohm) power
system], the system will be connected to earth potential through the varistor. This
may cause danger or damage the drive.
If a drive with its varistor connected is installed on a corner grounded TN system, the
drive will be damaged.
1. Ensure that the power is removed from the drive.
2. Remove the upper front cover by undoing the screws.
3. Disconnect the varistor cable.
4. Fasten the front cover.
3