EX9251 Power System

AC Power Supply Description

Each AC power supply weighs approximately 2.2 lb (1 kg) and has a handle, an ejection lever, an AC appliance inlet, a fan, and LEDs to monitor the status of the power supply. Figure 1 shows the power supply.

Each power supply requires a dedicated AC power feed and a dedicated customer-site circuit breaker. We recommend that you use a minimum 20 A (110 VAC) or 16 A (220 VAC) customer-site circuit breaker, or as required by local code.

Figure 1: AC Power Supply in an EX9251 Switch

AC Power Supply LEDs and Other Components

Figure 2 shows the LEDs and other components on an AC power supply without the AC power cord retainer installed.

Figure 2: LEDs and Other Components on an AC Power Supply Without the AC Power Cord Retainer Installed

1 — Handle	4 — Fault LED
2 — Input status LED	5 — Ejector lever
3 — Output status LED	6 — AC power cord retainer port

Figure 3 shows the LEDs and other components on an AC power supply with the AC power cord retainer installed.

Figure 3: LEDs and Other Components on an AC Power Supply With the AC Power Cord Retainer Installed

1 — Handle	4 — Fault LED
2 — Input status LED	5 — AC power cord retainer
3 — Output status LED	6 — Ejector lever

Table 1 describes the LEDs on the AC power supply.

DC Power Supply Description

Each DC power supply weighs approximately 2.2 lb (1 kg) and has a handle, an ejection lever, a fan, LEDs to monitor the status of the power supply, and a terminal block that provides a single DC input (–48 VDC and return) that requires a dedicated customer-site circuit breaker. We recommend that you use a dedicated customer-site circuit breaker rated for 25 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 and do not provision a 25 A (–48 VDC) circuit breaker, we recommend that you provision a dedicated customer-site circuit breaker for each DC power supply rated for at least 125 percent of the continuous current that the system draws at –48 VDC.Figure 4 shows the power supply.

Figure 4: DC Power Supply in an EX9251 Switch

DC Power Supply LEDs and Other Components

Figure 5 shows the DC power supply status LEDs and other components on a DC power supply.

Figure 5: DC Power Supply LEDs and Other Components on a DC Power Supply

1 — Input status LED	3 — Fault LED
2 — Output status LED

Table 2 describes the LEDs on the DC power supply.

Power Requirements for EX9251 Switch Components

Table 4 lists the power requirements for various hardware components when the switch is operating under typical and maximum voltage conditions.

Table 5 lists the power requirements for a fully configured AC-powered switch operating under typical voltage conditions.

Table 6 lists the power requirements for a fully configured AC-powered switch operating under maximum voltage conditions.

Calculating System Thermal Output

After you have calculated the power consumption for your configuration, you can use that information to determine the system thermal output (BTUs per hour). To do so, multiply the power consumption in watts by 3.41.

For example, in Table 5, we calculated the power consumption for a fully configured chassis running at high activity at 25°C typical temperature to be 240 W. Using that information, we can calculate the system thermal output for the configuration: