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🚚 Fast UK Dispatch 📦 Worldwide Delivery Available
⭐ Japanese Design, Build +Quality • Reliable Thermal Protection
🛡️ Designed for Motors, Transformers, Power Supplies, LED Drivers & Electronic Equipment
🌡️ Open Switch Temp ranges of 60°C • 70°C • 80°C • 90°C • 100°C
🔄 Normally Closed • Automatic Reset • Snap Action

Automatic Reset Thermal Switch SEKI ST-22

🔄 Automatic Reset Thermal Protection — resets after the switch cools
🌡️ Normally Closed Operation — opens at the selected temperature
📐 Compact & Space-Saving — ideal where installation space is limited
⚡ AC & DC Compatible — suitable for a wide range of applications
🔌 70 mm Insulated Lead Wires — supplied ready for installation
⚙️ Precision Snap-Action Bimetal Design — fast, reliable thermal switching
🛡️ International Safety Standards — designed for dependable thermal protection
🚚 Fast Worldwide Dispatch from the UK

The SEKI ST-22 is a compact automatic-reset bimetal thermal switch designed to protect electrical equipment from overheating. Using a precision snap-action bimetal mechanism, the switch opens the circuit when its calibrated temperature is reached and automatically reconnects once the device has cooled.

Its small footprint, reliable switching performance and sealed construction make it an excellent choice for motors, transformers, LED drivers, battery chargers, power supplies and many other industrial or commercial applications.

Thermal Fuse V Thermal switch

ST-22 is a resettable thermal switch

ST-22 Thermal Switch Thermal Fuse
Over-temperature protection ✓ ✓
Automatic reset ✓ ✗
Reusable ✓ ✗
Requires replacement after trip ✗ ✓
Good for repeated thermal cycling ✓ Usually no


Typical Applications

The ST-22 is widely used to provide over-temperature protection in:

  • Electric motors

  • Power transformers

  • LED drivers

  • Power supplies

  • Battery chargers

  • Solenoids

  • Heating elements

  • Lighting equipment

  • Industrial control systems

  • OEM electronic products

How It Works

Inside the ST-22 is a calibrated bimetal disc that reacts to temperature changes. Under normal operating conditions the contacts are closed, allowing current to flow. When the pre-set temperature is reached, the disc rapidly changes shape, opening the contacts and interrupting the electrical circuit.

As the device cools below its reset temperature, the contacts automatically close, restoring normal operation without requiring manual intervention.

Technical Specifications

Specification Value
Switch Type Automatic Reset Bimetal Thermal Switch
Operating Temperatures 50°C to 150°C
Temperature Tolerance 5°C
Contact Rating 7A @ 250VAC
DC Rating Up to 5A @ 24VDC (application dependent)
Reset Differential Approximately 30°C (typical)
Housing Material Epoxy-sealed PBT resin
Protection Rating IP45/IP65 depending on installation and version
Standard Lead Length 70 mm XLPE insulated leads
Mounting Option Surface mounting clip available


ST-22 Thermal Switch Dimensions

Package Includes

  • 1 × SEKI ST-22 Automatic Reset Thermal Switch

ST-22 Thermal Protection Approvals

SEKI

ST-22 Normally Closed Thermal Switch Automatic Reset UK

£1.75
£1.75
Temperature Cut Out:

🚚 Fast UK Dispatch 📦 Worldwide Delivery Available
⭐ Japanese Design, Build +Quality • Reliable Thermal Protection
🛡️ Designed for Motors, Transformers, Power Supplies, LED Drivers & Electronic Equipment
🌡️ Open Switch Temp ranges of 60°C • 70°C • 80°C • 90°C • 100°C
🔄 Normally Closed • Automatic Reset • Snap Action

Automatic Reset Thermal Switch SEKI ST-22

🔄 Automatic Reset Thermal Protection — resets after the switch cools
🌡️ Normally Closed Operation — opens at the selected temperature
📐 Compact & Space-Saving — ideal where installation space is limited
⚡ AC & DC Compatible — suitable for a wide range of applications
🔌 70 mm Insulated Lead Wires — supplied ready for installation
⚙️ Precision Snap-Action Bimetal Design — fast, reliable thermal switching
🛡️ International Safety Standards — designed for dependable thermal protection
🚚 Fast Worldwide Dispatch from the UK

The SEKI ST-22 is a compact automatic-reset bimetal thermal switch designed to protect electrical equipment from overheating. Using a precision snap-action bimetal mechanism, the switch opens the circuit when its calibrated temperature is reached and automatically reconnects once the device has cooled.

Its small footprint, reliable switching performance and sealed construction make it an excellent choice for motors, transformers, LED drivers, battery chargers, power supplies and many other industrial or commercial applications.

Thermal Fuse V Thermal switch

ST-22 is a resettable thermal switch

ST-22 Thermal Switch Thermal Fuse
Over-temperature protection ✓ ✓
Automatic reset ✓ ✗
Reusable ✓ ✗
Requires replacement after trip ✗ ✓
Good for repeated thermal cycling ✓ Usually no


Typical Applications

The ST-22 is widely used to provide over-temperature protection in:

  • Electric motors

  • Power transformers

  • LED drivers

  • Power supplies

  • Battery chargers

  • Solenoids

  • Heating elements

  • Lighting equipment

  • Industrial control systems

  • OEM electronic products

How It Works

Inside the ST-22 is a calibrated bimetal disc that reacts to temperature changes. Under normal operating conditions the contacts are closed, allowing current to flow. When the pre-set temperature is reached, the disc rapidly changes shape, opening the contacts and interrupting the electrical circuit.

As the device cools below its reset temperature, the contacts automatically close, restoring normal operation without requiring manual intervention.

Technical Specifications

Specification Value
Switch Type Automatic Reset Bimetal Thermal Switch
Operating Temperatures 50°C to 150°C
Temperature Tolerance 5°C
Contact Rating 7A @ 250VAC
DC Rating Up to 5A @ 24VDC (application dependent)
Reset Differential Approximately 30°C (typical)
Housing Material Epoxy-sealed PBT resin
Protection Rating IP45/IP65 depending on installation and version
Standard Lead Length 70 mm XLPE insulated leads
Mounting Option Surface mounting clip available


ST-22 Thermal Switch Dimensions

Package Includes

  • 1 × SEKI ST-22 Automatic Reset Thermal Switch

ST-22 Thermal Protection Approvals

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Total price£42.75

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