The temperature limit switch is a readily available accessory. It is a thermostat especially designed for overheat protection for small assemblies.

The thermal response is excellent due to its miniaturized housing. It becomes an effective thermal cutout due to the fact that this limit switch can be fitted close to the heatsink of the relay.

When connected serial with the control voltage, the TLS will switch off the relay as soon as the operating temperature of the switch is reached. The relay will be activated again when the temperature drops (approx. 30°C) below its cutout value.

In the RZ3 relay, the TLS can be connected to two free (internally non-connected) terminals (B1/B2).

Thermal compound must be added when inserting the TLS (to guarantee a fast thermal response).

The heatsink selection charts (load current versus ambient temperature) for RSO types provide information about which thermal switch to use.

Type Selection:

Switching temperature

UP 62-70 70°C (158°F)

UP 62-80 80°C (176°F)

UP 62-90 90°C (194°F)