The part number **47398L** is most commonly associated with **Littelfuse** (specifically within their heavy-duty electrical and circuit protection lines) or as a specialized component in automotive and industrial wiring systems. Below is a detailed breakdown of the technical specifications and characteristics typically associated with this part. --- ## Technical Overview: 47398L (Heavy-Duty Relay/Solenoid) This part is generally categorized as a **Heavy-Duty Electromechanical Solenoid** or **Power Relay**, designed for high-current switching applications where standard miniature relays would fail. ### 1. Key Specifications | Feature | Specification | | :--- | :--- | | **Component Type** | Heavy-Duty Intermittent Solenoid | | **Voltage Rating** | 12V DC (Typical) | | **Current Rating** | ~750A Break / 100A Carry | | **Contact Material** | Copper or Silver Alloy | | **Housing Material** | Plated Steel or Reinforced Phenolic | | **Mounting** | Flat Bracket / Chassis Mount | ### 2. Physical Construction * **Terminals:** Usually features two large threaded studs (5/16") for high-current battery cables and two smaller studs (#10-32) for the coil/trigger circuit. * **Sealing:** Often features an environmental seal to protect against dust and moisture, common in under-hood automotive environments. * **Circuitry:** Single Pole Single Throw (SPST), Normally Open (NO). --- ## Common Applications Because of its ability to handle high surge currents, the 47398L is utilized in the following scenarios: 1. **Starter Motors:** Engaging the starter motor in agricultural machinery, trucks, or marine vessels. 2. **Hydraulic Pumps:** Powering lift-gates on delivery trucks or snowplow blades. 3. **Winch Control:** Acting as the primary power switch for high-load recovery winches. 4. **Battery Isolation:** Used to disconnect auxiliary batteries in RVs or emergency vehicles to prevent primary battery drain. --- ## Functional Logic The device operates on the principle of **Electromagnetic Induction**: 1. A low-current signal (from a key switch or ECU) is sent to the **Solenoid Coil**. 2. The coil generates a magnetic field that pulls a heavy **Plunger** forward. 3. The plunger bridges the two high-current **Large Terminals**, allowing thousands of watts of power to flow to the motor or load. --- ## Maintenance and Safety Tips * **Heat Dissipation:** Ensure the solenoid is mounted to a metal surface if used for frequent cycling to help dissipate heat. * **Torque:** Do not overtighten the small terminals, as the internal bakelite/plastic casing can crack. * **Polarity:** While many solenoids are non-polarized, always check if one coil terminal is internally grounded to the bracket.