System information

Dell
PowerEdge M1000e Technical Guide 25
Figure 19. M1000e Power Supply Back View
The Dell power supplies use output ORing FETs to isolate the power supply from the 12V system bus.
If a single power supply fails its output ORing FET, the power supply will turn off removing itself from
the bus like an electrical switch that turns off when the power supply fails.
When Dynamic Power Supply Engagement (DPSE) is enabled, the PSU units move between on and off
states depending on actual power draw conditions to achieve high power efficiency.
In the N+N power supply configuration, the system will provide protection against AC grid loss or
power supply failures. If one power grid fails, three power supplies lose their AC source, and the
three power supplies on the other grid remain powered, providing sufficient power for the system to
continue running. In the N+1 configuration, only power supply failures are protected, not grid
failures. The likelihood of multiple power supplies failing at the same time is remote. In the N+0
configuration, there is no power protection and any protection must be provided at the node or
chassis level. Typically this case is an HPCC or other clustered environment where redundant power
is not a concern, since the parallelism of the processing nodes across multiple system chassis
provides all the redundancy that is necessary.
The midplane carries all 12V DC power for the system, both main power and standby power. The
CMCs, LCD, and control panel are powered solely by 12V standby power, ensuring that chassis level
management is operational in the chassis standby state, whenever AC power is present. The server
modules, I/O modules, fans, and iKVM are powered solely by 12V main power.