Eaton Moeller CMD, Руководство пользователя

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10/12 MN04913001Z-EN
1 CMD contactor monitoring relays
Application of the CMD In the event of an emergency in safety-related electrical
control circuits, the hazardous plant section is shut down
from the main power supply by means of contactors
a Emergency stop (stopping in the event of an emergency)
in accordance with IEC/EN 60204-1.
For Category 3 control systems in compliance with EN/ISO
13849, the connection of two contactors in series is recom-
mended. This technique can be replaced using one contactor
and the CMD contactor monitoring device connected to the
backup circuit-breaker/motor-protective circuit-breaker in
the plant.
The contactors must be provided with an auxiliary NC
contact that operates as a mirror contact in accordance with
IEC/EN 60947-4-1 Annex F. The contactors also require an
additional auxiliary NO contact. The motor-protective circuit-
breakers/circuit-breakers are provided with an undervoltage
release.
In the event of a hazard the contactor is disconnected via an
upstream safety PLC or a safety relay by means of an enable
contact. The CMD compares the control voltage of the
contactor with the status of the main contacts. The status of
the main contacts is monitored via an auxiliary NC contact
that acts as a mirror contact in accordance with IEC/
EN 60947-4-1 Annex F.
If the contactor is welded, the status of the main contacts
does not correspond to the status of the control voltage. The
undervoltage release of the backup circuit-breaker is tripped
via an internal relay in the CMD. This disconnects the
outgoer. The undervoltage release prevents the welded
contactor from be switched on again.