Allied Telesis AT-PBC18 - Manual (Page 31)

21
Chapter 4
Installing a Power Supply Module
The PowerBlade PBC18 has two expansion slots: one for the main power
supply and one for an optional power supply. The power module installed in
the PWR 1 expansion slot is referred to as the main power supply. The power
module installed in the PWR 2 expansion slot is referred to as the optional
power supply.
An optional power supply, when installed, shares the load of powering the
chassis with the main power supply. This is known as “load-sharing.” In the
event the main power supply fails, the optional power supply will provide full
power to the chassis, thereby preventing a system failure.
The main and optional power supply can be “hot swapped,” meaning that
should either power supply fail, the failed power supply can be removed and
replaced with a new power module while the chassis is operating. Network
operation will not be interrupted. The power modules to be hot swapped must
be the same type. You cannot install an AC power supply and a DC power
supply together in the same chassis.
Powering ON or OFF the chassis depends on the type of power supply
installed. For an AC model, you connect or disconnect the power cord. For a
DC model, you connect or disconnect the DC power cables or power OFF the
DC circuit to which the power supply is connected.