User`s guide

134 NovaScale 4020 User’s Guide
Hot-swap Power Supplies
The power subsystem contains the power bay. The power bay includes the AC transfer switch,
the power distribution logic, and locations for the three hot-swappable Thin Power Supply
modules (TPS). TPS positions are labled AC1/PS1, AC2/PS2, and PS Shared. The power
system is rated at 650-watts; the requirements of a fully-loaded system require that at least two
operational TPS modules (350-watts each) be installed at any one time. A fully redundant
power configuration requires three modules be installed, with the third module (PS Shared)
acting as standby module in case one of the first two modules fails.
When a failure occurs, the AC transfer switch will immediately fail-over to the standby TPS
module in the PS-shared position. The failing TPS module can be removed and replaced
without powering down the server. After replacing the failed TPS module, the AC transfer
switch will engage the replaced module and set the module in the PS-Shared position back to
standby.
See Power Supply Bay on page 8 and Power Subsystem on page 16 for more information.
NOTES
A system operating in a two TPS configuration should have a TPS filler
panel installed in the PS-Shared position to optimize cooling. Server
systems that are shipped with with two TPSs have a filler panel installed
at the factory.
Determining Power Supply Status
Each TPS module has a bi-color LED at the top left corner of the module that indicates the
status and health of the module. Table 28 provides more detail on the LEDs.
Table 28. Power Supply LEDs
Power Supply Condition Power Supply LED
No AC power to any PSU
Off
No AC power to this PSU only Amber
AC present / Only standby outputs on Blink green
Power supply DC outputs on and ok Green
Power supply failure (includes over voltage and over
temperature)
Amber
Current limit Amber