After removing the connection of the internal mains filter to PE, the device is not classified in respect
of emitted interference in accordance with EN 61800-3. External filter measures are required.
When operating servo drives in IT networks, the distributor must provide an EMC concept for the over-
all system.
This comprises as a minimum:
–
A concept for feeding the converter leakage currents back into the converter intermediate circuit
(Y capacitors to the intermediate circuit)
–
Use of external filter measures such as mains filter and converter output filter
Earth-leakage monitor
For IT systems, an earth-leakage monitor is required so that an insulation fault between the mains
phase and PE can be detected immediately. An insulation fault must be rectified immediately after
detection.
Interrupting the connection of the internal mains filter to PE (for IT networks only)
Before using the CMMT-AS in IT networks, the internal connection of the integrated mains filter to PE
must be interrupted. Interrupting the connection prevents unwanted disconnection on faults of the
device and damage to the integrated filter. The connection of the mains filter to PE is interrupted by
removing a screw in the lower area of the right-hand side of the housing.
To unscrew the screw, lever out the housing element in front of the screw. A protective cap for sealing
the recess in the housing is included in the delivery of the plug set NEKM-C6-...-S and NEKM-C6-...-D
(accessories from Festo).
To interrupt the connection of the filter capacitors to PE:
1. Completely disconnect the servo drive from the power supply.
2. Wait 5 minutes until the intermediate DC circuit has discharged.
Fig. 9 Levering out the housing element
3. Place a suitable screwdriver against the upper notch in the housing recess provided and carefully
lever the housing element out using the screwdriver.
Installation
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Festo — CMMT-AS-C2/C4-3A-... — 2018-02
