Digital Equipment AlphaServer 2000, Owner'S Manual

Page: 135 / 196

Power Supply Configurations
Power Supply
Modes
The power supplies for AlphaServer 2000 systems support three
different modes of operation. In addition, UPS options are
available.
Power supply modes of operation:
1. Single power supply—Supports systems with:
— One CPU
— Two memory modules
— One diskette drive
— Two removable drives
— Eight 3.5-inch StorageWorks hard disks
— Ten I/O slots
2. Dual power supply (redundant mode)—Provides redundant
power (n + 1) for the system described above.
In redundant mode, the failure of one power supply does not
cause the system to shut down. Normal operation continues
with no impact on the system.
The power supply mode jumper (J3) on the I/O backplane
module must be installed to activate redundant mode power.
Figure 3–11 shows the jumper installed
!
and the jumper
not installed
"
.
3. Dual power supply (full power mode)—Provides full power for
systems with two CPUs. If you purchased a system with two
CPUs, or plan to upgrade to two CPUs, you need a second
power supply.
If you have two power supplies, the current share cable
should be installed between them, as shown in Figure 3–12.
Options and Upgrades 3–51