The **FAN-7002H-R** is a specific fan assembly typically used in server rack environments, most notably associated with Cisco Nexus series switches (like the Nexus 7000 series). Below is a detailed breakdown of its electronic components, specifications, and architecture. --- ### 1. Technical Specifications This unit is a high-performance, hot-swappable fan tray designed for mission-critical cooling. | Parameter | Specification | | :--- | :--- | | **Input Voltage** | 12V DC (Nominal) | | **Max Current** | Variable based on RPM (High-draw during boot) | | **Airflow Direction** | Front-to-Back (Port-side Exhaust) | | **Hot Swappable** | Yes | | **Compatibility** | Cisco Nexus 7002 Chassis | | **Redundancy** | N+1 Internal Fan Redundancy | --- ### 2. Key Electronic Components The assembly is not just a plastic housing; it contains several sophisticated electronic layers: #### A. DC Brushless Motors (BLDC) * **Commutation:** Uses electronic commutation instead of brushes, reducing mechanical wear and electrical noise. * **Bearings:** Typically utilizes dual-ball bearings for a high Mean Time Between Failures (MTBF). * **Stator/Rotor:** Permanent magnet rotor with a multi-pole stator coil configuration. #### B. Control PCB (Printed Circuit Board) Every FAN-7002H-R contains an internal logic board that manages: * **PWM (Pulse Width Modulation):** Receives signals from the chassis supervisor engine to adjust speed based on thermal sensors. * **Tachometer Output:** Sends a "Tach" signal back to the system to monitor actual RPM. * **I2C / EEPROM:** Contains an identification chip that tells the switch the part number, serial number, and power requirements upon insertion. #### C. Status Indicators (LEDs) * **Status LED:** A bi-color LED (Green/Amber). * *Green:* Normal operation. * *Amber:* Fan failure or individual motor stall detected. --- ### 3. Pinout & Interconnect The fan tray connects to the backplane via a high-density blind-mate connector. The wiring logic generally follows this structure: ```cpp // Logic-level representation of the Connector Pins Pin 1: VCC (+12V Power) Pin 2: GND (Return) Pin 3: PWM Control (Speed Input) Pin 4: Tachometer (Speed Feedback) Pin 5: Presence (Ground link to notify system of insertion) Pin 6: I2C Data (SDA/SCL for FRU inventory data) ``` --- ### 4. Advanced Features * **Soft Start Logic:** To prevent high inrush current that could trip the power supply, the internal electronics ramp the motors up slowly. * **Locked Rotor Protection:** If an object obstructs the blades, the controller cuts power to the motor to prevent the coils from burning out.