4
EMI
All electromagnetic interference (EMI) sources, from outside or inside of the switch and application
system, adversely affect the switch in the following ways:
•
A conduction pattern of capacitance coupling.
•
Inductance coupling.
•
Electromagnetic wave radiation.
•
Common impedance (including the grounding system) coupling.
To prevent EMI, perform the following tasks:
•
If AC power is used, use a single-phase three-wire power receptacle with protection earth (PE)
to filter interference from the power grid.
•
Keep the switch far away from radio transmitting stations, radar stations, and high-frequency
devices to make sure the EMI levels do not exceed the compliant range.
•
Use electromagnetic shielding, for example, shielded interface cables, when necessary.
•
To prevent signal ports from getting damaged by over-voltage or over-current caused by
lightning strikes, only route interface cables indoors.
Grounding
Using a good grounding system to protect your switch against lightning shocks, interferences, and
ESD is essential to the operating reliability of your switch. Make sure the resistance between the
chassis and the ground is less than 1 ohm. For more information about the grounding methods of the
7500 switches, see "Installing the switch."
Power
Perform the following steps to satisfy the power supply requirements of the 7500 switches:
1.
Calculate the total power consumption
The total power consumption of a 7500 switch depends on module type and quantity and fan
tray power consumption. If the switch provides PoE power, the total power consumption also
depends on PoE power consumption. For more information about the total power consumption
of the 7500 switches, see "Appendix A Chassis views and technical specifications."
2.
Select power supplies according to the total power consumption
To ensure correct operation of the switch, make sure the maximum output power of the power
supply that supplies power to the switch is higher than the total power consumption of the
switch. After determining the total power consumption of the switch, you can select appropriate
power supplies according to the total power consumption. For more information about the
optional power supply models, see "Appendix B FRUs and compatibility matrixes."
3.
Verify that the power supply system on the installation site satisfies the input requirements of
the power supplies and parameters such as rated voltage.
Cooling
For adequate heat dissipation, plan the installation site according to the airflow of your switch, and
adhere to the following requirements:
•
Leave a clearance of a minimum of 10 cm (3.94 in) around the air inlet and outlet vents.
•
The rack for installing the switch has a good cooling system.
•
The installation site has a good cooling system.
