The **HFE27-AS/3-1DTG-L2-R** is a specific part number for a high-power magnetic latching relay manufactured by **Hongfa**. These relays are primarily used in smart meters and smart home energy management systems. --- ### Part Number Breakdown The following table decodes the specifications based on the manufacturer's nomenclature: | Code Segment | Feature | Description | | :--- | :--- | :--- | | **HFE27** | Series | High-power magnetic latching relay series | | **AS** | Contact Load | Standard power rating (Specific to HFE27 design) | | **3** | Rated Voltage | 3V DC coil voltage | | **1D** | Contact Form | 1 Form B (Single Pole Single Throw - Normally Closed) | | **TG** | Contact Material | AgSnO₂ (Silver Tin Oxide) for high inrush currents | | **L2** | Coil Type | Dual coil (Double-winding) latching | | **R** | Polarity | Standard polarity configuration | --- ### Technical Specifications This relay is designed for switching high current loads while maintaining low power consumption. * **Switching Capacity:** Capable of handling up to **100A** (standard for HFE27 series) at 250VAC. * **Latching Mechanism:** Being a **Latching Relay**, it only requires a short pulse of energy to switch states. Once switched, it remains in that position without needing continuous power to the coil. * **Dielectric Strength:** Typically 4kV between coil and contacts, providing high insulation. * **Creepage Distance:** Designed to meet international standards for electricity meters (e.g., IEC 62055-31). ### Key Application Areas 1. **Smart Electricity Meters:** Used for remote disconnection and reconnection of power. 2. **Electric Vehicle (EV) Charging:** Managing power flow in AC charging stations. 3. **Solar Inverters:** Used for grid connection and safety isolation. 4. **IoT Power Switches:** Large-scale building automation for heavy appliances. --- ### Wiring and Control (L2 Dual Coil) Since this is an **L2 (Dual Coil)** model, it has three pins for the coil: * **Pin 1:** Reset pulse. * **Pin 2:** Common connection. * **Pin 3:** Set pulse. To flip the relay, you apply a pulse (approx. 50ms to 100ms) to the specific coil winding. This prevents the component from heating up and significantly reduces energy waste in the system. ---