Generic KSD9700/BK05-BB1D Metallic Shell Temperature Control Switch - 40°C NC, 5A 250V

This KSD9700/BK05-BB1D switch is rated for 5 Amperes at 250 Volts, compatible with both AC and DC circuits. It is configured as Normally Closed (NC), meaning the circuit is complete under normal conditions and opens to break the connection when the temperature reaches its 40°C setpoint.

The switch uses a bimetallic disc that snaps between two positions based on temperature. When the ambient temperature rises to 40°C, the disc snaps open, breaking the circuit. Once the temperature cools sufficiently below the setpoint (typically by 5-10°C), the disc snaps back to its original position, automatically closing the contacts and restoring the circuit without manual intervention.

Install the switch in direct thermal contact with the component or area you need to monitor (e.g., motor housing, heatsink). Connect its two wire leads in series with the load (e.g., heater, motor) you wish to control or protect. Ensure the metallic shell is securely mounted for optimal thermal transfer. The switch is not polarized, so either wire can be connected to the source or load side.

While primarily designed as a safety cut-off, its discrete on/off action at a fixed temperature can be used for simple on/off control in applications like maintaining a minimum temperature in an enclosure or activating a cooling fan. It is not suitable for proportional or precise temperature feedback, as it provides only a binary signal (open/closed) at its single setpoint.