The Hekatron THM 442 is a Wall Mounted Electromagnetic Door Retainer. The THM 442 is used to keep self-closing doorways, such as fire doors, smoke doors and other doors or gates open. The THM-442 must be connected to a smoke detection system, which will break the circuit to de-energize the electromagnet, if a fire occurs. This will allow the door to close, and stop the fire from spreading.
The Hekatron THM442 has a hermetically sealed terminal box with a PG cable gland. Both the pole face and the mating counter plates have an electroplated nickel finish. The THM442 is rated IP65, making it suitable for use in hazardous area Zone 2.
The THM 442 is provided with a spark-suppression diode (free-wheeling diode) to protect the contacts against premature erosion and voltage surges, plus a reverse polarity protection diode.
