Juniper Networks M160 manual Fuses, Cooling System

Hardware Component Overview

Figure 19: Circuit Breaker Box

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Fuses

The router uses fuses from the Cooper Bussman brand GMT series for the FPCs, MCSs, PCGs, and SFMs. The fuses are located in a fuse box on the rear of the midplane. When the fuse for a component blows, the component stops functioning even though it is installed correctly and the power supplies are providing power to the router. For more information, see “Blown Fuse Indicators” on page 211. For fuse replacement instructions, see “Replacing a Fuse” on page 204.

Cooling System

The cooling system includes a fan tray and several impellers that draw room air into the chassis to keep its internal temperature below a maximum acceptable level. When the temperature is below the maximum, the fans and impellers function

at less than full speed. If the MCS detects that the temperature of a component has exceeded the acceptable maximum—for example, because an impeller is removed—it automatically increases the speed of the remaining impellers and fans to reduce the temperature. The fans and impellers can function at the higher speed indefinitely.

For more information about the cooling system, see the following sections:

Cooling System Components on page 40

Airflow through the Chassis on page 40

Cooling System 39