KSD301 Snap Disc Thermostat, Flat Terminals, Fixed Ring, 180°C, Normally Closed

Product Description:

Qimao  Disc Thermostat KSD301 Snap Disc Thermostat, Flat Terminals, Fixed Ring, 180°C, Normally Closed unit uses a 1/2″ bimetal disc as the sensing element. At 180°C (±5°C tolerance), the disc snaps from convex to concave, driving the single-pole single-throw contact open. The circuit closes again after cooling—standard differential is 10–30K . Flat terminals accept 6.3mm quick-connect or direct solder. The fixed ring seats against the heated surface, ensuring repeatable thermal coupling across production runs. Housing is heat-resistant phenolic, rated for 220°C max continuous exposure. Contact life exceeds 50,000 actuations under resistive load. Auto-reset configuration. No arc suppression circuit required for most applications.

Specification:

Working Principle:

The KSD301 Snap Disc Thermostat, Flat Terminals, Fixed Ring, 180°C, Normally Closed uses a bimetallic disc as both the sensing element and the switching mechanism. At room temperature the disc stays convex, holding the normally closed contact together. When the mounting surface reaches 180°C, the disc snaps to concave, pushing the contact open and cutting power to the load. As the surface cools, the disc snaps back at the reset point, typically 10–30K below the action temperature, and the contact closes again. There is no coil, no spring, and no external sensor—the disc does everything. This is why response is fast and repeatable, and why the trip point does not drift with age.

Features:

• The product KSD301 Snap Disc Thermostat, Flat Terminals, Fixed Ring, 180°C, Normally Closed,180°C fixed action temperature, ±5°C tolerance
  The bimetal disc snaps within a narrow band around 180°C. No field calibration, no adjustment drift over time.

• Normally closed SPST, opens on temperature rise
  Circuit is closed at room temperature and opens when the disc reaches 180°C. Fail-safe logic for overheat protection.

• Automatic reset, 10–30K differential
  Contact re-closes after the surface cools below the reset threshold. No manual reset button needed.

• Flat terminals, 6.3mm width
  Standard quick-connect or direct solder. Low wiring profile, fits tight appliance layouts.

• Fixed ring mounting
  Seats the housing flat against the heated surface for repeatable thermal contact and consistent trip points.

• ≤50mΩ circuit resistance
  Low voltage drop at rated current, less self-heating at the contact.

• Silver contacts, 10A/250VAC resistive
  Resists oxidation and pitting. Rated for 50,000+ cycles at resistive load.

• Snap action with minimal arcing
  Fast contact opening reduces arc duration and RF interference. Suitable near control electronics.

• Heat-resistant phenolic housing
  Rated for 220°C max continuous exposure, giving headroom above the 180°C action point.

Application:

• KSD301 Snap Disc Thermostat, Flat Terminals, Fixed Ring, 180°C, Normally Closed for electric kettles and water dispensers
  Dry-boil cutoff on the heating plate. Auto-reset version re-closes after cooling.

• Rice cookers and food warmers
  Overheat limit on the main heating plate. Narrow differential helps hold stable warm temperature.

• Microwave ovens
  Thermal cutoff on the magnetron or cavity wall. Opens before the magnetron overheats.

• Space heaters and fan heaters
  Overheat protector on the heating element. Opens if airflow is blocked or the fan stalls.

• Clothes dryers
  Limits exhaust air temperature. Fixed ring keeps the sensing surface against the duct wall.

• Coffee makers and espresso machines
  High-limit cutoff on the boiler or heating block. 10A rating covers most small heating elements.

• Industrial heating plates
  Surface temperature limit on hot plates and small industrial heaters. Can drive a relay for higher loads.

• Automotive seat heaters
  Prevents overheating if the controller fails or the seat is covered. Compact body fits under seat foam.

Customization Service:

We build KSD301 Snap Disc Thermostat, Flat Terminals, Fixed Ring, 180°C, Normally Closed in-house, which means customization starts at the disc—not at the assembly line. Action temperature can be set anywhere from 40°C to 220°C, and we adjust disc heat treatment and contact gap to match your trip point and differential requirements. Flat terminals can be bent, lengthened, or changed to different widths. Fixed ring dimensions, housing height, and lead wire length are all open to modification. If you send us your appliance model, load current, and mounting space, we can match a thermostat to your design rather than forcing your design around a standard part. Samples typically ship within 7–10 days.