Note: for most applications, a single power supply can power a 7750 SR-a4 system.

However, Alcatel-Lucent recommends calculating the maximum power consumption of all chassis components and installing a second power supply if necessary. For the 7750 SR-a8, two power supplies are required to meet all system needs if you are operating without power.

Three power supplies must be installed and powered at all times to ensure redundancy (N + 1). All unused slots must be equipped with impedance panels to maintain electromagnetic interference containment and adequate airflow within the chassis.

The cooling system is designed to keep the internal components within an acceptable temperature range. The cooling system for the 7750 SR-a4 and 7750 SR-a8 includes the following components: • a fan tray • an air filter with a reusable metal frame and a site-replaceable filter • the air intake on the right side and the exhaust on the left side of the chassis

The 7750 SR -a system is cooled by variable-speed fans housed in a fan tray. Air is drawn into the system through a filtered intake located on the right side, through the chassis and the line components, and then exits through the fan tray located on the left side of the chassis.

The fan speed is reduced to normal temperatures and gradually increases to maximum speed as the ambient temperature rises. The fan trays are energy-efficient and meet NEBS3 acoustic requirements.