The **FCA-1A-R** is a specific type of high-performance **electromagnetic relay** manufactured by **TE Connectivity (CII brand)**. These components are designed for high-reliability environments, primarily in the aerospace, defense, and military sectors. Below is a breakdown of its electronic parts, specifications, and architecture. --- ### 1. General Specifications The FCA-1A-R is a mid-range power relay. The alphanumeric code typically indicates its configuration: | Feature | Specification | | :--- | :--- | | **Contact Arrangement** | 1 Form C (SPDT - Single Pole Double Throw) | | **Contact Rating** | 25 Amperes | | **Coil Voltage** | 28 VDC (Nominal) | | **Termination** | Stud Terminals (typically) | | **Mounting** | Raised Vertical Brackets | | **Standard** | MIL-PRF-6106 (Military Grade) | --- ### 2. Internal Electronic Components #### A. The Electromagnetic Coil The heart of the relay is the coil. When energized with 28 VDC, it creates a magnetic field that pulls the armature. * **DC Resistance:** Usually calibrated for specific power consumption to ensure the relay triggers at the "Must Operate" voltage (approx. 18VDC). * **Duty Cycle:** Designed for continuous duty. #### B. Contact System The "1A" in the series often refers to the contact power level. * **Materials:** Contacts are typically made of **Silver Cadmium Oxide** or similar alloys to prevent "welding" (sticking) under high current loads. * **Arcing Control:** Because it handles 25A, the internal geometry is designed to extinguish electrical arcs quickly to prevent damage to the contact surfaces. #### C. Hermetic Sealing The "R" suffix and the general FCA series build involve a **hermetically sealed** enclosure. * **Environment:** The internal parts are cleaned and the casing is filled with an inert gas (usually Nitrogen) and sealed. This prevents oxidation of the contacts and ensures functionality at high altitudes (low pressure). --- ### 3. Connection and Wiring Diagram The FCA-1A-R usually features a 3-terminal or 5-terminal layout depending on the specific sub-variant: ```text [Coil +] ----( Coil )---- [Coil -] | [Common (C)] / \ [Normally Closed] [Normally Open] (NC) (NO) ``` --- ### 4. Key Applications Due to its rugged construction, this relay is found in: 1. **Aviation Control:** Switching fuel pumps or hydraulic actuators. 2. **Military Vehicles:** Power distribution for onboard electronics. 3. **Space Systems:** High-vibration environments where standard industrial relays would fail. ---