EX9204 Power System

AC Power Supply Description

The AC power supplies in EX9204 switches are fully redundant, load-sharing, and hot-insertable and hot-removable field-replaceable units (FRUs).

You can install up to four AC power supplies in an EX9204 switch. Power supplies are installed in the rear of the chassis in slots PEM0 through PEM3 (left to right).

Each AC power supply weighs approximately 6.6 lb (2.99 kg) and consists of one AC appliance inlet, an AC input switch, a fan, and LEDs to monitor the status of the power supply. See Figure 1.

Figure 1: AC Power Supply for an EX9204 Switch

Each power supply has its own fan and is cooled by its own internal cooling system.

EX9204 switches support 2520 W AC power supply. The AC power supply supports the low-line (100–120 VAC) and the high-line(200–240 VAC) AC power configurations.

Each AC power supply has a single AC appliance inlet located on the power supply that requires a dedicated AC power feed. We recommend that you use a customer site circuit breaker rated for 16.0 A @ 100 VAC or 16.0 A @ 200 VAC circuit breaker minimum for each AC power supply, or as required by local code. Doing so enables you to operate the switch in any configuration without upgrading the power infrastructure.

AC Power Supply Configurations

The EX9204 switch supports either the low-line (100–120 V) AC power configuration or the high-line (200–240 V) AC power configuration.

• In the low-line (100–120 V) AC power configuration, the EX9204 switch contains either two AC power supplies in base AC configuration, located horizontally at the rear of the chassis in slots PEM0 and PEM1 (left to right); or four AC power supplies in the redundant AC configuration, located in slots PEM0 through PEM3 (left to right). Each AC power supply provides power to all components in the switch.

  The low-line configuration requires minimum two power supplies to provide the maximum configuration with full power for as long as the switch is operational. When only two power supplies are present, they share power almost equally within a fully populated system and removing one of the power supply will disturb switch functions. Four AC power supplies provide full power redundancy; if one power supply fails or is removed, the remaining power supplies assume the entire electrical load without interruption.

• In the high-line (200–240 V) AC power configuration, the EX9204 switch contains either one power supply in the base AC configuration, located horizontally in the slot PEM0; or two power supplies in the redundant AC configuration, located in slots PEM0 and PEM2 (left to right). In a high-line AC power configuration, each AC power supply provides power to all components in the switch.

  In high-line configuration, one power supply provide the maximum configuration with full power for as long as the switch is operational. Two power supplies provide full power redundancy; if one power supply fails or is removed, the remaining power supply assume the entire electrical load without interruption. The high-line configuration requires one power supply, with the second providing redundancy. See AC Power Supply Specifications for EX9204 Switches.

Ensure that you install sufficient number of power supplies to provide the power necessary for the line cards you install in the switch. See Power Requirements for EX9200 Switch Components to know the power required by each component in the switch and AC Power Supply Specifications for EX9204 Switches for the power supply specifications including the output power provided by the power supplies.

Table 1 shows an example for power requirement calculation. To install three EX9200-32XS line cards in the switch, the power required is 2300 W, calculated as shown in the table:

The output power provided by each low-voltage line power supply is 1167 W and the output power provided by each high-voltage line power supply is 2050 W.

Starting in Junos OS Release 18.4R1, on EX9204 switches, the enhanced AC PEM in the high-line power configuration supplies a power output of 2400 W. On Junos OS versions prior to 18.4R1, the PEM provided 2050 W of power output.

Therefore, to provide sufficient power to support three EX9200-32XS line cards, you must install at least two low-voltage line or high-voltage line power supplies in the switch.

DC Power Supply Description

The DC power supplies in EX9000 switches are fully redundant, load-sharing, and hot-insertable and hot-removable field-replaceable units (FRUs).

You can install two DC power supplies in an EX9204 switch. Power supplies are installed in the rear of the chassis in slots PEM0 and PEM2 (left to right).

A DC power supply weighs approximately 6.2 lb (2.81 kg) and consists of one DC input (–48 VDC and return), one 70 A (–48 VDC) circuit breaker, a fan, and LEDs to monitor the status of the power supply. See Figure 3.

Each DC power supply has a single DC input (–48 VDC and return) that requires a dedicated circuit breaker. We recommend that you provision 60 A or 75 A per feed, depending on the selected DIP switch setting. If you plan to operate a maximally configured DC-powered switch with DC power supplies, we recommend that you use a dedicated customer site circuit breaker rated for 70 A (–48 VDC) minimum, or as required by local code.

If you plan to operate a DC-powered switch at less than the maximum configuration, we recommend that you provision a circuit breaker according to respective National Electrical Code and customer site internal standards to maintain proper level of protection for the current specified above or each DC power supply rated for at least 125% of the continuous current that the system draws at –48 VDC.

Figure 3: DC Power Supply for an EX9204 Switch

DC Power Supply Configurations

In the DC power configuration, the EX9204 switch comes with two DC power supplies located at the rear of the chassis in slots PEM0 and PEM2 (left to right). One power supply provide the maximum configuration with full power for as long as the switch is operational. Two power supplies provide full redundancy; if one power supply fails or is removed, the redundant power supply takes over without interruption. . A single DC power supply provides power to all components and the second DC power supply provides redundancy. See DC Power Supply Specifications for EX9204 Switches.

Ensure that you install sufficient number of power supplies to provide the power necessary for the line cards you install in the switch. See Power Requirements for EX9200 Switch Components to know the power required by each component in the switch and DC Power Supply Specifications for EX9204 Switches for the power supply specifications including the output power provided by the power supplies.

Table 6 shows an example for power requirement calculation. To install three EX9200-32XS line cards in the switch, the power required is 2300 W, calculated as shown in the table:

The output power provided by each power supply is at least 2400 W.

Therefore, one DC power supply can provide sufficient power to support three EX9200-32XS line cards.