Chapter 2 Preparing for Installation
Ventilation
Appendix A, “Specifications,” lists the operating and nonoperating environmental site requirements for the switches. To maintain normal operation and ensure high system availability, maintain an ambient temperature and clean power at your site. The environmental ranges listed in Appendix A, “Specifications,” are those within which the switch will continue to operate; however, a measurement that approaches the minimum or maximum of a range indicates a potential problem. You can maintain normal operation by anticipating and correcting environmental anomalies before they exceed the maximum operating range.
Calculating System Heat Dissipation
To calculate the expected heat dissipation from a switch, add the total amount of power drawn from power supply by the system's configuration, then divide the total amount of power by the efficiency of the power supply. Multiply the result by 3.415 to get the system heat dissipation in BTUs/hr.
First example (System without any powered devices):
Components
Output Power
1 | - Catalyst 4506 with fans | 50 W |
1 | - Supervisor Engine IV | 145 W |
1 | - | 72 W |
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| total output power | 267 W |
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Total heat dissipated by system = (267/.75) * 3.415 = 1215 BTUs/hr
Note All Catalyst 4000/4500 power supplies have different efficiencies, An average efficiency figure of 75% was chosen.
Second example (same system but this time with one IEEE class 3 device):
Components
Output Power
1 - Catalyst 4506 with fans
1 - Supervisor Engine IV
1 -
50W
145W
72W
| Catalyst 4500 Series Switches Installation Guide |
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