The **HFE39-1/3-2DST-L2-R** is a high-power, polarized bistable (latching) magnetic relay typically used in smart meters, lighting control, and industrial automation. --- ### 1. Part Number Breakdown The nomenclature reveals the specific technical characteristics of the device: | Segment | Meaning | Detail | | :--- | :--- | :--- | | **HFE39-1** | Series Name | High-power subminiature latching relay series. | | **3** | Rated Coil Voltage | 3V DC operating voltage. | | **2D** | Contact Arrangement | 2-Pole (Double Pole), Form A (Normally Open). | | **S** | Protection Structure | Sealed (Plastic sealed) for environmental protection. | | **T** | Contact Material | AgSnO₂ (Silver Tin Oxide) for high inrush resistance. | | **L2** | Coil Type | Dual Coil Latching (Two coils for Set/Reset). | | **R** | Polarity | Reversed polarity configuration. | --- ### 2. Key Technical Specifications Below are the typical electrical and mechanical limits for this specific model: | Parameter | Specification | | :--- | :--- | | **Contact Capacity** | 32A @ 250VAC | | **Coil Power** | Approx. 1.0W to 2.0W (Pulse driven) | | **Dielectric Strength** | 4,000VAC (between coil and contacts) | | **Mechanical Life** | 1,000,000 operations | | **Electric Life** | 10,000 operations (at rated load) | | **Dimensions** | Approx. 39.0 x 15.0 x 30.2 mm | --- ### 3. Core Electronic Features #### A. Dual Coil Latching (L2) Unlike standard relays that require constant power to stay "on," this is a **bistable** relay. * **Operation:** A short voltage pulse (typically 50ms to 100ms) on one coil "Sets" the relay, and a pulse on the second coil "Resets" it. * **Benefit:** Zero power consumption once the state is changed, making it ideal for energy-efficient or battery-powered applications. #### B. Contact Material (AgSnO₂) The use of Silver Tin Oxide allows the relay to handle high inrush currents (such as those from LED drivers or motors) without welding the contacts together. #### C. High Switching Capacity Designed for heavy loads up to **32A**, which is significantly higher than standard PCB-mount signal relays. --- ### 4. Typical Applications * **Smart Energy Meters:** Remote disconnection and reconnection of electricity. * **Lighting Controls:** Handling high inrush currents in commercial LED arrays. * **Industrial Controls:** Power distribution units (PDUs) and motor control.