AC Power Supply in a QFX3008-I Interconnect Device

The AC power supply in a QFX3008-I Interconnect device is a hot-insertable and hot-removable field-replaceable unit (FRU).

The QFX3008-I Interconnect device has six power supplies and two wiring trays. Power supplies are installed at the rear bottom of the chassis in slots 0 through 5 (left to right when viewed from the rear of the chassis). Wiring trays are installed at the rear bottom of the chassis on either side of the power supplies. The wiring tray in slot Wiring Tray 0 provides input power to the power supplies in slots 0 through 2. The wiring tray in slot Wiring Tray 1 provides input power to the power supplies in slots 3 through 5.

Warning: The chassis is pluggable type A equipment installed in a restricted-access location. It has a separate protective earthing terminal provided on the chassis. This separate protective earthing terminal must be permanently connected to earth ground.

Note: The QFX3008-I Interconnect device has two protective earthing terminals provided on the rear of the chassis. Only one of these protective earthing terminals needs to be permanently connected to earth ground. The first pair is sized for M6 screws and is located below the wiring tray on the bottom left corner at the rear of the chassis. The second pair is sized for UNC ¼-20 screws and is located below the second wiring tray on the bottom right corner at the rear of the chassis. The grounding points are spaced at 0.625 in. (15.86 mm).

Each power supply is cooled by its own fans. The airflow is from the front of the power supply to the back. Hot air exhausts from the rear of the chassis. Three LEDs on the faceplate indicate the status of the power supply. See Figure 1.

Figure 1: AC Power Supply

Each power supply contains two isolated 2000-W channels that produce 54 VDC. The midplane distributes the output power produced by the power supplies to different system components.

The distribution of power to the QFX3008-I Interconnect device is divided between components, and each power supply provides power to different components. Together, the three power supplies in slots 0 through 2 provide power for the entire system. Likewise, the power supplies in slots 3 through 5 also provide power to the entire system. In standard power redundancy terminology, the two sets of three power supplies provide 2N redundancy for the QFX3008-I Interconnect device, where N is the number of power supplies.

Because each power supply provides power to a subset of components, a second power supply that provides power to the same components must be installed for redundancy. For example, during normal operation the power supplies in slot 1 and slot 4 provide power to the same components on a load-sharing basis. If the power supply in slot 1 fails, the power supply in slot 4 can provide full power to the components indefinitely.

Table 1 lists the pairs of power supplies and the components they power in a QFX3008-I Interconnect device.