The Hekatron THM 439/485 is an Electromagnetic Door Retainer for wall, floor or ceiling mounting. The THM 439/485 is used to keep self-closing doorways, such as fire doors, smoke doors and other doors or gates open. The THM 439/485 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 head of the THM 439/485 can be turned and tilted, making it possible to arrange the pole face parallel to the mounting surface or at right angles to it. The length of the THM 439/485 can be adjusted to suit local conditions by shortening its tubular support.
The THM 439/485 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.
