The **PWR-500AC-R** is a specific Power Supply Unit (PSU) designed primarily for enterprise-grade networking hardware, such as the Cisco Nexus 3000 and 9000 series switches. The "R" in the model name indicates **Red (Reverse/Exhaust) Airflow**, meaning the air flows from the front of the chassis and exits out the back (Port-side Intake). --- ### Technical Specifications The following table highlights the core electronic and operational parameters: | Feature | Specification | | :--- | :--- | | **Input Voltage Range** | 90V to 264V AC | | **Nominal Input Voltage** | 100V to 240V AC | | **Input Frequency** | 47 Hz to 63 Hz | | **Output Capacity** | 500 Watts | | **Efficiency Rating** | 80 Plus Platinum (typically >90%) | | **Airflow Direction** | Port-side Intake (Red color-coded) | | **Hot Swappable** | Yes | --- ### Key Electronic Components & Functions 1. **AC-to-DC Rectification Stage**: * Converts the incoming alternating current (AC) from the wall outlet into a stable direct current (DC). * Features **Power Factor Correction (PFC)** circuitry to reduce harmonic distortion and improve energy efficiency. 2. **Internal Cooling System**: * Contains a high-speed internal fan module. * The "R" designation means the fan is polarized to pull air over the switch components and push it out the power supply faceplate. 3. **Protection Circuitry**: * **Over-Voltage Protection (OVP):** Shuts down the unit if the output voltage exceeds safe limits to protect the switch's motherboard. * **Over-Current Protection (OCP):** Prevents damage from short circuits or excessive power draw. * **Thermal Sensors:** Monitors internal heat and adjusts fan speed or triggers an emergency shutdown if temperatures exceed safety thresholds. 4. **Status Monitoring (I2C Bus)**: * The unit communicates with the switch's CPU via an I2C management bus. * It reports serial numbers, temperature data, fan speed, and power consumption statistics to the Network Operating System (e.g., Cisco NX-OS). --- ### Indicators and Connectivity * **LED Indicators:** Usually features a "Status" LED. Green indicates normal operation; Amber indicates a fault or a "Power Standby" mode where input is present but output is disabled. * **Connector Type:** Standard IEC C14 inlet for AC power input.