Cisco CRS-1 System Description page 47

Cooling System
3 Fan tray handle
Each fan tray contains:
• Four fans: Each fan uses a nominal -54 VDC as its input power. The PWM (pulse-width modulation)
signals are adjusted to increase or decrease the speed of the fan. The fans operate:
The fan speed range limits listed in this document are nominal, with a lower tolerance range of minus 5 percent.
The upper tolerance ranges are as follows:
•
• A fan tray board: The board terminates signals to and from the fans, filters common-mode noise, and
contains tracking and indicator parts.
• A front-panel status LED: The LED indicates the following:
• 2950 up to 5450 RPM for normal range
• 6500 RPM for single fan tray failure
• 2950rpm—13.6%
• 3600rpm—20.3%
• 4400rpm—21.9%
• 5000rpm—23.7%
• 5450rpm—24.0%
• 6500rpm—18.5%
• Green: The fan tray is operating normally.
• Yellow: The fan tray has experienced a failure and should be replaced.
• Off: An unknown state exists or the LED is faulty (there is no input power).
Cisco CRS Carrier Routing System 8-Slot Line Card Chassis Enhanced Router System Description
Cisco CRS 8-Slot Line Card Chassis Enhanced Router Fan Tray
37