MK 9163N ATEX and MK 9003 ATEX avoid reliably thermal overload on motors. The devices of the VARIMETER EX series of DOLD monitor and protect standard motors and explosion proof motors equipped with PTC resistors fulfilling the directive 94/9/EC.
The devices that are tested for functional safety (EN 50495, EN 61508 und EN ISO 13849) are used in applications with harsh environment or conditions e.g. fast switching cycles, heavy duty starting or limited power dissipation due to dirty environment.
The main features of the thermistor motor protection relays MK 9163N ATEX and MK 9003 ATEX are overtemperature detection, broken sensor wire detection and sensor short circuit detection. If one sensor in the monitoring circuit reaches the response temperature value the monitoring device indicates a fault via its output contacts.
The thermistor motor protection relay MK 9003 ATEX in the variant with no voltage proof fault memory stores the failure status also on loss of power. The reset of the fault has to be done by using the built in reset button or an external connected remote reset.