AC Power Supply in EX4500 Switches
The AC power supply in EX4500 switches is a hot-insertable and hot-removable field-replaceable unit (FRU).
EX4500 switches are shipped with one power supply. A cover panel is installed in the second power supply slot. You can add a second power supply to the switch.
Power supplies are installed at the rear of the chassis in slots labeled 1 and 0. Both power supplies are accessible from the rear of the chassis.
 | Warning: The switch is pluggable type A equipment installed in a restricted-access location. It has a separate protective earthing terminal provided on the chassis in addition to the grounding pin of the power supply cord. This separate protective earthing terminal must be permanently connected to earth ground. See Connecting Earth Ground to an EX Series Switch |
Each AC power supply weighs approximately 3 lb (1.3 kg) and has an independent 12 A rated AC appliance inlet on its front. Each inlet requires a dedicated AC power feed. Each AC power supply has a fan, a bicolor LED on the faceplate that indicates the status of the power supply, and a colored ejector lever. See Figure 1.
Figure 1: AC Power Supply
Each AC power supply has an ejector lever that holds the power supply in place. The ejector lever locks into the corresponding hole in the chassis on the left side of the AC appliance inlet. For instructions for installing the power supply, see Installing a Power Supply in an EX4500 Switch.
Each AC power supply comes with a power cord retainer that holds the power cord in place. See Figure 2. The power cord retainer has a clip and an adjustment nut. The L-shaped ends of the retainer clip hook into the bracket holes on each side of the AC appliance inlet. The adjustment nut holds the power cord in the correct position. For instructions for installing the power cord retainer, see Installing a Power Supply in an EX4500 Switch.
Figure 2: Power Cord Retainer for an AC Power Supply
Each power supply has its own fan and is cooled by its own internal cooling system. The airflow for a power supply is either from the front of the power supply to the back or from the back of the power supply to the front depending on the switch model you purchase.
The color of the ejector lever on the power supply indicates the direction of airflow of the power supply.
- Green—Front-to-back airflow
- Orange—Back-to-front airflow
The color of the power supply's ejector lever must match the color of the intake or exhaust label visible through the vents of the installed fan tray. The color match indicates that the direction of airflow through the fan tray matches the direction of airflow through the power supply.
 | Caution: Verify that the direction of airflow through the power supply matches the direction of airflow through the fan tray to prevent overheating of the chassis. |
Each AC power supply provides power to all components in the switch. The two power supplies provide full power redundancy to the switch. If one power supply fails or is removed, the second power supply balances the electrical load without interruption. The switch reassesses the power required to support the switch configuration and issues error messages if the available power is insufficient.
The output for the AC power supply is 12 VDC. The output power is 1000 W.
