Meridian America 21, 51, 61, 71 Internal power distribution

20 DC power system description
Internal power distribution
Figure 9 shows the internal DC power distribution elements:
- Pedestal Power Distribution Unit (PDU)
- Module to Module Harness
- Module to Backplane Harness
- DC Power Converters
The power cables enter the Pedestal and connect to an internal terminal block
located in the pedestal. From there, the DC voltage enters the Power
Distribution Unit (PDU) which has five circuit breakers, one for each of the
four modules and one for the cooling fans. The System monitor runs off a
DC-to-DC converter. Module to Module distribution brings individual DC
power to each module similar to AC distribution.
Pedestal Power Distribution Unit (PDU)
The Pedestal PDU provides the following:
- The Field Wiring Terminal Block provides a connection point in the
bottom of the Pedestal for the external wiring.
- The Circuit Breakers provide individual Module protection devices for
Module overload currents and a single trip function to shut down the
Stack in the event of a thermal overload.
- The Internal Terminal Block provides individual power hand-off points so
that each Module is independently powered from the Pedestal in order to
minimize wire size.
- The Power/Signal Harness provides the Power and Signal connections in
the PDU for the Blower Unit and System Monitor.
- The System Monitor Power Supply (a small +5V DC-DC Converter)
provides power to the System Monitor, even when all of the Circuit
Breakers have been tripped.
- The Output Power Harness provides the independent power connections
from the Pedestal to the Module above it.
Power engineering 553-3001-l 52