3Com 9000 manual Overheat Power Down Mode

Managing Power Systems 33

■The EME may shut down selected interface modules in an attempt to bring installed module power consumption under the now-reduced power budget.

In power fault-tolerantmode, power equivalent to one power supply is held in reserve. This reserve power is not available to installed modules unless a power supply fails, or if you switch the power mode from power fault-tolerant mode to power non-fault-tolerant mode.

While the chassis is running in power fault-tolerant mode:

■All installed power supplies are functioning and contributing power to the chassis and modules. No single power supply is a dedicated standby power supply. Rather, a factory-defined power limit ensures that power that is equivalent to at least one power supply is available to replace power lost if a power supply fails.

■The amount of power that installed modules require must not be greater than the number of installed power supplies, minus one (n-1). When you reserve power that is equivalent to one power supply in power fault-tolerant mode, the failure of a single power supply has no impact on installed modules that are already powered on.

If a power supply fails while the chassis is running in fault-tolerant mode:

■The EME automatically disables fault-tolerant mode.

■Power formerly reserved is made available to modules to prevent them from powering off.

■All modules that had power before the power supply failure continue to receive power without interruption.

■Upon power supply recovery (or replacement), the EME automatically reenables fault-tolerant mode.

Overheat Power Down Mode

An overheat condition exists when one of the chassis temperature sensors detects a chassis internal operating temperature that exceeds a predefined threshold. The allowable ambient temperature operating range is 0 °C through 50 °C (32 °F through 122 °F). The default threshold setting is fixed at an upper limit of 60 °C (140 °F) or higher to prevent module damage.