Fan Tray Assembly

Replacement Fan Tray Assembly for the 8820 Broadband Loop Carrier

Model 8820-S3-900

Installation Instructions

Document Number 8820-A2-GZ48-00

January 2005

The fan tray assembly is a dedicated cooling device installed in the chassis of the 8820 Broadband Loop Carrier (BLC) to provide forced–air cooling of the chassis. The fans, located at the top of the BLC chassis, draw cooling air upwards from the bottom of the chassis, through the circuit cards or card cage, forcing the air out the opening, located at the top rear of the chassis.

The fan tray assembly consists of six fans, a metal bracket, and a printed wiring board (PWB) with a press-fit connector and five status LEDs. Each fan provides a sense wire that indicates the status of the fan. The sense wires are connected to the backplane via the fan tray’s PWB and its connector.

The rated airflow is 900 cfm (based on 6 fans at 150 cfm each) at zero back pressure.

The fan tray is powered by –48 or –60 VDC from the backplane of the 8820 BLC. Nominal power consumption is less than 100 watts.

An LED is on the fan tray so that if a fan failure occurs, a signal is sent to the SCP card or MCP card and the yellow Fan ALARM LED on the chassis lights. Removal of the fan tray also causes the SCP card or MCP card to sense an alarm.

The fan tray assembly weighs 10 lbs (22 kg). It is secured by two fan-locking brackets located on the right and left front of the assembly.

8820-A2-GZ48-00