The thermistor relay is used as a protective relay for motors against thermal overload (unacceptable heating). This heating can occur due to mechanical overload on the shaft or when the motor is operated with unacceptable voltages. A PTC thermistor is used as a sensor, which is placed on the part of the motor that heats up the most when overloaded (e.g. integrated in the motor winding). The device can also be used with motors that have an integrated thermal switch. Integrated error memory with reset button on the front, or connection of an external reset button (terminals B1 - B2). Variants: 230 V AC or 24 V AC/DC 1 changeover contact or 2 changeover contacts Operating voltage AC 230 V AC Operating voltage AC/DC 24 V AC/DC Pick-up delay 10 ms Input / thermistor voltage 12 V Input / thermistor current 1 mA Input / switch-on resistance 1.8 kOhm Input / switch-off resistance 3.0 kOhm, +/- 5% Output / contact 1 changeover contact (SPDT) or 2 changeover contacts (DPDT) Output / switching voltage 250 V Output / continuous current 4 A Mechanical life 3 x 107 switching cycles Electrical life 1 x 105 switching cycles Switching frequency 1200 switching cycles/h Display LED green, red Dimensions W x H x D 22.5 x 75 x 95 mm Weight 150 g Operating temperature range 0 °C to +55 °C Storage temperature range -20 °C to +70 °C Protection class Housing / terminals IP40 / IP20
