Generic KSD301 140°C NC Thermostat Switch - Bakelite Housing, 250V 10A

Yes, the KSD301 is an automatic reset thermostat. Once the bimetallic disc cools below its setpoint (typically a few degrees below 140°C), the contacts will automatically close again, restoring the circuit. This cycle repeats each time the temperature rises and falls around the actuation point.

A Normally Closed (NC) thermostat, like this KSD301, has contacts that are closed at normal temperatures, allowing current to flow. When the set temperature (140°C) is exceeded, the contacts open, breaking the circuit to stop the connected device (e.g., a heater). A Normally Open (NO) thermostat does the opposite, closing the circuit to activate a device (like a fan) when a high temperature is reached.

Yes, you can safely use this switch in a 12V DC system. The 250V rating is the maximum voltage it can withstand. The current rating of 10A is the critical limit; ensure your DC load does not exceed 10A. The switch's operation is voltage-independent, relying solely on thermal actuation of the bimetallic disc.

For optimal thermal response, mount the thermostat's metal sensing face (typically the side opposite the terminals) directly against the surface or component you wish to monitor, using the provided mounting holes. Ensure good mechanical and thermal contact, often using thermal paste or a mounting clamp, to minimize response lag and accurately reflect the target's temperature.