Eaton CMD Manual

Also see for CMD: Original operating instructions Manual Instruction leaflet Instruction leaflet

Contents

1 CMD contactor monitoring device1.1 Application of the CMD24 CMD(220-240VAC), CMDB 12/17 MN121002ZU-DEEN www.eaton.com1 CMD contactor monitoring device1.1 Application of the CMDIn the event of an emergency in safety-related electrical control circuits, thehazardous plant section is shut down from the main power supply by meansof contactors a Emergency stop (stopping in the event of an emergency) inaccordance with IEC/EN 60204-1.For Category 3 control systems in compliance with EN/ISO 13849, theconnection of two contactors in series is recommended. This technique canbe replaced using one contactor and the CMD contactor monitoring deviceconnected to the backup circuit-breaker/motor-protective circuit-breaker inthe plant.The contactors must be provided with an auxiliary NC contact that operatesas 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 undervoltagerelease.In the event of a hazard the contactor is disconnected via an upstream safetyPLC or a safety relay by means of an enable contact. The CMD compares thecontrol voltage of the contactor with the status of the main contacts. Thestatus of the main contacts is monitored via an auxiliary NC contact that actsas 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 notcorrespond to the status of the control voltage. The undervoltage release ofthe backup circuit-breaker is tripped via an internal relay in the CMD.This disconnects the outgoing section. The undervoltage release preventsthe welded contactor from be switched on again.The CMD contactor monitoring device is approved by the IFA in combinationwith Eaton contactors and circuit-breakers (￫ section 1.2, “Systemoverview”, page 24).A CE declaration of conformity and a prototype test certification are alsoavailable.1.2 System overviewFigure 1: Contactor monitoring devicesThe CMD contactor monitoring device requires a control power supply.• CMD(220-240VAC), CMDB:Control voltage 220 to 240 V, 50/60 Hz