KSD9700 150C Thermal Switch Normally Closed 5A 250V Bimetal Protector

The KSD9700-150 is a normally closed bimetal thermal switch that opens its contacts when the sensed temperature reaches 150°C and closes again automatically after the temperature falls to the reset point. It is built around a dish-shaped high-sensitivity bimetallic element that snaps from one state to the other at the calibrated action temperature, driving a movable contact away from a stationary contact and interrupting the circuit. Because the contact state is normally closed, the KSD9700 thermal switch keeps the appliance energised during normal operation and only breaks the circuit on overheating, which makes it a series safety element rather than a control thermostat. The switch is rated for 5A at 250V AC, uses a metal or aluminium case depending on the variant, and is supplied with two lead wires for in-line connection. Its compact body and fast response suit motors, transformers, battery chargers, fluorescent ballasts, solenoids, heating pads, and office machines, as well as household appliances such as electric kettles and microwave ovens. This 150C temperature switch is a practical, auto-resetting thermal protector for equipment that must be disconnected before heat causes damage.

1. Overheating protection for electric motors in appliances and power tools.
2. Thermal protection of transformers, battery chargers, and power supplies.
3. Fluorescent ballasts and lighting control gear.
4. Solenoids, heating pads, and office machines (OA equipment).
5. Household appliances such as electric kettles and microwave ovens.
6. Automotive, cooling system, and industrial equipment requiring a 150C temperature switch.

1. Model: KSD9700-150.
2. Switch type: normally closed (NC), auto-reset.
3. Action temperature: 150°C.
4. Rated voltage: 250V AC.
5. Rated current: 5A.
6. Body material: aluminium (metal case variant).
7. Dimensions: 20.7 × 3.8 × 7.4 mm (metal case, per source page).
8. Lead wire length: 70 mm (per distributor listings).
9. Contact resistance: less than 50 mΩ.
10. Insulation resistance: greater than 100 MΩ.
11. Dielectric strength: greater than 800V.
12. Response speed: 1°C per minute or faster.
13. Operating temperature range (series): 20°C to 180°C (tolerance ±3°C or ±5°C).
14. Reset temperature range (series): 10°C to 140°C (tolerance ≤15°C).
15. Life: greater than 10,000 cycles (per source page); distributor listings state 100,000 cycles.
16. Sensing element: dish-shaped bimetallic disc.