Thermal Cutoffs (Thermal Fuses)

Image Part Number Description / PDF Quantity Rfq
NTE8010

NTE8010

NTE Electronics, Inc.

THERMAL FUSE 102*C RADIAL

19408

NTE8070

NTE8070

NTE Electronics, Inc.

THERMAL FUSE 72*C AXIAL

252

NTE8213

NTE8213

NTE Electronics, Inc.

THERMAL FUSE 216*C AXIAL

7479

NTE8081

NTE8081

NTE Electronics, Inc.

THERMAL FUSE 84*C AXIAL

5168

NTE8182

NTE8182

NTE Electronics, Inc.

THERMAL FUSE 192*C AXIAL

4376

NTE8167

NTE8167

NTE Electronics, Inc.

THERMAL FUSE 169*C AXIAL

5481

NTE8025

NTE8025

NTE Electronics, Inc.

THERMAL FUSE 136*C RADIAL

8084

NTE8030

NTE8030

NTE Electronics, Inc.

THERMAL FUSE 145*C RADIAL

1345

NTE8242

NTE8242

NTE Electronics, Inc.

THERMAL FUSE 240*C AXIAL

6800

NTE8085

NTE8085

NTE Electronics, Inc.

THERMAL FUSE 87*C AXIAL

484

NTE8005

NTE8005

NTE Electronics, Inc.

THERMAL FUSE 86*C RADIAL

2800

NTE8098

NTE8098

NTE Electronics, Inc.

THERMAL FUSE 100*C AXIAL

2960

NTE8000

NTE8000

NTE Electronics, Inc.

THERMAL FUSE 76*C RADIAL

3154

NTE8020

NTE8020

NTE Electronics, Inc.

THERMAL FUSE 130*C RADIAL

6643

NTE8125

NTE8125

NTE Electronics, Inc.

THERMAL FUSE 128*C AXIAL

6408

NTE8115

NTE8115

NTE Electronics, Inc.

THERMAL FUSE 117*C AXIAL

6147

NTE8139

NTE8139

NTE Electronics, Inc.

THERMAL FUSE 142*C AXIAL

7489

NTE8076

NTE8076

NTE Electronics, Inc.

THERMAL FUSE 77*C AXIAL

2735

NTE8096

NTE8096

NTE Electronics, Inc.

THERMAL FUSE 98*C AXIAL

6768

NTE8226

NTE8226

NTE Electronics, Inc.

THERMAL FUSE 228*C AXIAL

3392

Thermal Cutoffs (Thermal Fuses)

1. Overview

Thermal cutoffs, also known as thermal fuses, are non-resettable overtemperature protection devices designed to interrupt electrical circuits when temperatures exceed predefined thresholds. They act as critical safety components in electrical and electronic systems, preventing overheating-related failures, fires, or equipment damage. These devices are widely used in appliances, industrial machinery, and automotive systems due to their reliability and compliance with international safety standards.

2. Main Types and Functional Classification

TypeFunctional CharacteristicsApplication Examples
Single-shot Thermal FusesOne-time use; permanently breaks circuit after activationHousehold appliances (e.g., hair dryers, coffee makers)
Auto-resetting Thermal SwitchesResets automatically after cooling; limited cycle lifePower tools, battery packs
High-Temperature CutoffsOperates above 150 C; ceramic-based constructionIndustrial ovens, heating elements
Low-Temperature CutoffsTriggers below 100 C; polymer-based materialsConsumer electronics, LED lighting

3. Structure and Components

Typical thermal cutoffs consist of:

  • Temperature-sensitive element: Bimetallic strip, fusible alloy, or polymer-based material
  • Contact system: Silver-plated contacts for low resistance
  • Insulation housing: Flame-retardant thermoplastic or ceramic materials
  • Termination: Axial leads, radial leads, or surface-mount pads

Advanced designs incorporate hermetically sealed chambers for environmental protection and precise calibration mechanisms for accurate trip temperatures.

4. Key Technical Specifications

ParameterImportanceTypical Range
Rated Temperature ( C)Determines activation threshold accuracy50-300 C 3 C tolerance
Rated Current (A)Defines maximum operational current capacity0.1-15A
Response Time (ms)Time to interrupt circuit after threshold breach10-500ms
Reset TypeManual vs. automatic recovery capabilityNon-resettable/partial auto-reset
Dielectric Strength (V)Insulation resistance under overvoltage1500-5000VAC

5. Application Fields

  • Consumer Electronics: Smartphones (battery protection), power adapters
  • Home Appliances: Washing machines (motor protection), rice cookers
  • Industrial Equipment: Transformers, CNC machine tools
  • Automotive: Battery management systems, HVAC units

Case Study: In electric kettles, thermal cutoffs prevent boil-dry damage by disconnecting heating elements at 158 C 5 C.

6. Key Manufacturers and Products

ManufacturerRepresentative ProductKey Features
LittelfuseThermal Cut-Off (TCO) SeriesUL/CSA certified, 85-240 C range
TE ConnectivityKlixon 1TS SeriesMiniature SMD package, 5A rating
OmronThermal Protector KSD SeriesAuto-reset function, 10,000 cycle endurance

7. Selection Guidelines

  • Match rated temperature to system's maximum safe operating temperature
  • Verify current/voltage ratings exceed circuit requirements
  • Consider environmental factors (vibration, humidity, thermal cycling)
  • Select appropriate form factor (through-hole, SMD, panel mount)
  • Check compliance with safety standards (UL 1434, IEC 60675)

8. Industry Trends

Future developments include:

  • Nanomaterial-based temperature sensors for faster response times
  • Integration with IoT-enabled thermal management systems
  • Miniaturization for wearable electronics (sub-5mm packages)
  • Eco-friendly designs eliminating cadmium-based alloys
  • AI-driven predictive thermal cutoff systems
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