25
IS7 0.75–22 kW (3 phase) inverters have EMC filters built-in and activated as a
factory default design. An EMC filter prevents electromagnetic interference by
reducing radio emissions from the inverter. EMC filter use is not always
recommended, as it increases leakage current. If an inverter uses a power source
with an asymmetrical grounding connection, the EMC filter must be turned off.
Asymmetrical Grounding Connection
One phase of
a delta
connection is
grounded
(TN Systems)
Intermediate
grounding
point on one
phase of a
delta
connection
(TN
Systems)
The end of a
single phase
is grounded
(TN Systems)
A 3-phase
connection
without
grounding
(TN
Systems)
•
200 V products require Class 3 grounding. Resistance to ground must be
≤
100 Ω.
•
400 V products require Special Class 3 grounding. Resistance to ground must be
≤
10 Ω.
•
Keep the ground wire connections as short as possible.
•
Do not ground one inverter to another in a “daisy chain” fashion.
Follow the motor manufacturer wiring requirements.