The **FTG-52-R** is a specific type of thermal fuse (thermal cutoff) manufactured by **UCHIYA**. It is primarily designed as a safety component to protect electrical appliances from overheating by permanently breaking the circuit when a specific temperature is reached. --- ### Technical Specifications | Parameter | Details | | :--- | :--- | | **Type** | Thermal Cutoff (Non-Resettable) | | **Rated Functioning Temperature ($T_f$)** | 52°C | | **Holding Temperature ($T_h$)** | Approx. 37°C | | **Voltage Rating** | 250V AC | | **Current Rating** | 2A to 5A (depending on specific model variation) | | **Construction** | Ceramic or Resin body with axial leads | --- ### Key Components and Construction 1. **Thermal Element:** A heat-sensitive pellet or fusible alloy that melts at exactly 52°C. 2. **Spring Mechanism:** Once the thermal element melts, a pre-loaded spring pushes the contacts apart. 3. **Housing:** Usually a ceramic or high-temp plastic casing to prevent electrical leakage after the fuse has tripped. 4. **Lead Wires:** Tinned copper wires used for soldering or crimping into the circuit. ### Working Principle The FTG-52-R operates as a **One-Shot Operation** device: * **Normal State:** The circuit is closed, and electricity flows through the internal contacts. * **Overheat State:** If the ambient temperature reaches **52°C**, the internal fusible element melts. * **Open State:** The internal spring forces the contacts to separate. The circuit is permanently broken to prevent fire or damage. * **Replacement:** Unlike a circuit breaker, once this part activates, it **cannot be reset** and must be replaced. ### Common Applications * **Small Household Appliances:** Coffee makers, rice cookers, and hair dryers. * **Power Supplies:** Protecting transformers and PCB components from thermal runaway. * **HVAC Systems:** Used in fan motors or heaters as a fail-safe. * **Battery Packs:** To prevent overheating during charging or discharging cycles. --- ### Installation Safety Notes > [!CAUTION] > When soldering the FTG-52-R, use a heat sink (like a pair of pliers) on the lead between the fuse body and the soldering iron. Excessive heat from the iron can accidentally trigger the fuse during installation.