Dell PowerConnect J-8208, Руководство по оборудованию

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3.
Calculate the maximum system power consumption by dividing the maximum internal
power consumption by the efficiency of the power supply. This accounts for the loss
of energy within the power supply.
NOTE: The efficiency of a 2000 W AC power supply is approximately 90
percent when input voltage is high line (200–240 VAC).
The efficiency of a 2000 W AC power supply is approximately 87 percent
when input voltage is low line (100–120 VAC).
For example, for a switch fully loaded with 8-port SFP+ line cards and using N+1 power
redundancy with high-line input voltage, the maximum system power consumption:
= (maximum internal power consumption) / (power supply efficiency)
= (5200 W) / (0.90)
= 5778 W
Calculating System Thermal Output for Your J-EX8208 Switch Configuration
Use the following procedure to calculate the system thermal output in British thermal
units (BTU) per hour for your switch configuration.
To calculate the system thermal output:
1.
Determine the maximum system power consumption of your switch in watts. See
“Calculating the Power Consumption of Your J-EX8208 Switch Configuration” on
page 79 for how to do so.
2.
Multiply the maximum system power consumption by 3.41.
For example, for a switch fully loaded with 8-port SFP+ line cards and using N+1 power
redundancy with high-line input voltage, the system thermal output:
= (maximum system power consumption) x (3.41)
= (5778 W) x (3.41) =
= 19,703 BTU/hr
NOTE: Using the maximum system power consumption values to calculate
the system thermal output often results in overprovisioning the cooling
systems. Typical power consumption is about one-third lower than these
calculated values.
Calculating the Number of Power Supplies Required for Your J-EX8208 Switch Configuration
Use this procedure to calculate the number of power supplies required by your switch
configuration. The required power configuration for J-EX8208 switches is N+1. You can
optionally configure your switch for N+N configuration. For example, you might want
dual power feed redundancy with AC power supplies, which requires an N+N configuration.
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Chapter 7: Planning Power Requirements