Ground-To-Phase Varistor - ABB ACS380 Hardware Manual

64 Electrical installation
The EMC grounding screw is
located on the bottom of the
frame in R3 and R4 frames.

Ground-to-phase
varistor
The metallic varistor screw
(VAR) connects the varistor
protection circuit to electrical
ground.
To disconnect the varistor
circuit from ground, remove
the varistor grounding screw.
Refer to Hardware overview
on page 28.
In some product variants, the
varistor protection circuit is
disconnected from electrical
ground at the factory with a
non-conducting (plastic)
screw.
WARNING! If you connect the drive to an IT system (an ungrounded power
system or a high-resistance-grounded [over 30 ohms] power system),
disconnect the varistor from ground. Failure to do so can cause damage to the
varistor circuit.