Motor protection based on PTC sensors is one of the most effective and reliable protective measures against thermal overload in electrical machines.
The protection unit is composed of the INT69 TM motor protector and the PTC sensors. Due to its compact construction, the INT69 TM is suitable for installation in electrical devices or in the terminal boxes of electrical machines.
At the measuring circuit input of the INT69 TM, it is possible to connect up to nine DIN 44081, DIN 44082 conform PTC sensors. Sensors with different nominal response temperatures may be used. Thus it is possible to monitor several measuring points with only one INT69 TM motor protector.
If the temperature in one of the monitored parts or sections reaches the nominal response temperature of the respective PTC sensor, the sensor becomes highly resistive and the motor protector switches off.
After cooldown or elimination of the error and a subsequent reset delay, the machine can be restarted. The relay's switching output is a potential-free changeover contact.This circuit works in accordance with the closed-circuit principle, i.e.even in the event of a sensor or cable break, the relay returns to its rest position and switches off.
The sensor, relay and supply current circuits are galvanically isolated from each other.
INT-69 TM 22A463S021