The **TN-R-35** is a high-performance, rotary-action electronic thermal protector (or circuit breaker) typically used in industrial machinery, heavy-duty power tools, and household appliances. Its primary function is to monitor current flow and disconnect the circuit if an overload or overheating occurs. --- ### 1. Key Electronic & Mechanical Components The device operates using a combination of thermal-sensing elements and mechanical switching components. | Component | Function | Description | | :--- | :--- | :--- | | **Bimetallic Strip** | Sensing Element | Two bonded metals with different expansion rates that bend when heated by excessive current. | | **Heating Coil** | Current Monitor | A resistive wire that generates heat proportional to the current passing through the device. | | **Silver Alloy Contacts** | Switching | High-conductivity points that open or close the circuit. Silver prevents oxidation and pitting. | | **Reset Button/Knob** | Manual Interface | A rotary or push-mechanism that allows the user to re-engage the circuit after a trip. | | **Phenolic Housing** | Insulation | High-temperature resistant plastic casing that prevents electrical arcing and heat damage. | --- ### 2. Technical Specifications The "35" in the model name usually refers to the **Amperage (35A)** or a specific frame size depending on the manufacturer. * **Rated Voltage:** Usually 125V AC to 250V AC. * **Trip Current:** 35 Amperes (standard for this specific model variant). * **Operating Temp:** -10°C to +60°C. * **Reset Type:** Manual Reset (TO-type) or Automatic (depending on specific sub-series). --- ### 3. Functional Operation The TN-R-35 utilizes the **Inverse Time Characteristic** principle: 1. **Normal Flow:** Current passes through the heating coil and bimetallic strip without causing enough heat to deform the metal. 2. **Overload Detection:** When current exceeds 35A, the heating coil warms the bimetallic strip. 3. **Mechanical Trip:** The strip bends sufficiently to trigger a spring-loaded latch, snapping the silver contacts open. 4. **Cooling & Reset:** Once the strip cools down, the user can manually rotate or press the reset button to restore the connection. --- ### 4. Circuit Diagram Representation In an electrical schematic, the TN-R-35 is represented as a thermal overload switch: ```text (Line) L1 ----[ Thermal Element ]----(Contact / \ )---- L2 (Load) | (Manual Reset) ```