Siemens SINAMICS S120 Device Manual page 474

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8.35 L87, insulation monitoring
Description
On ungrounded systems (IT systems), the insulation monitor checks the entire electrically-
connected circuit for insulation faults. The insulation resistance as well as all insulation faults
from the line supply to the motors in the Cabinet Modules are detected Two response values
(between 1 kΩ and 10 MΩ) can be set. If a set value is undershot, an alarm is output to the
terminal. A system fault is output via the signaling relay system.
In its factory state, the Cabinet Module is not configured for a specific plant constellation
(one or several loads in one electrically-connected network) or protection concept
(immediate shutdown in the event of an insulation fault or restricted continued operation), as
these are unknown. The signaling relays of the insulation monitor must be integrated into the
fault and alarm circuit by the customer.
Note
Number of insulation monitors
Only one insulation monitor can be used within one electrically-connected network.
Removal of the connection clip to the interference suppression capacitor for operation in an IT system
When operating the devices on an IT system, the connection clip to the interference
suppression capacitor must be removed in the following Cabinet Modules:
● Basic Line Modules
● Smart Line Modules
( the connection clip is located behind the fan for frame sizes HX and JX)
● Active Line Modules (connection clip in the Active Interface Module)
For the positions of the connection clips in the respective Cabinet Modules, see the section
"Connection of the Cabinet Modules to ungrounded systems (IT systems)".
Controls and displays on the insulation monitor
Figure 8-48
474
Controls and displays on the insulation monitor
Cabinet Modules NEMA
Manual, 04/2014, A5E03586450A