User's Manual

18 4Motion System Manual
Chapter 1 - System Description
1.3.4 PIU
The single-Euro Power Interface Unit module serves as the interface between the
DC power source and both the PSU modules and external ODU radio transceivers.
The PIU filters and stabilizes the input power, and protects the system from power
problems such as over-voltage, surge pulses, reverse polarity connection, and
short circuits. It filters high-frequency interference (radiated emissions) and
low-frequency interference (conducted emissions) at the external power source.
Each shelf contains two slots for optional 1+1 PIU redundancy. One PIU is
sufficient to support a fully populated shelf, and two modules provide redundant
power feeding (i.e. from two input sources), while avoiding current flow between
the two input sources.
1.3.5 PSU
The single-Euro Power Supply Unit module is a -48 VDC power supply unit that
generates low-voltage DC output to comply with PICMG 2.x standard
requirements. Each shelf can contain up to four PSU modules supporting N+1
redundancy configuration scheme.
Table 1-2 displays the number of PSU modules (excluding redundant units)
required for various Base Station configurations without NPU redundancy (one
NPU):
1.3.6 AVU
The 2U-high AVU includes a 1U-high integral chamber for inlet airflow and a
1U-high fan tray with an internal alarm module. To support high availability, the
fan tray includes 10 brushless fans (9 fans are sufficient for cooling a fully-loaded
shelf). Fan failure is indicated by both the front panel LEDs and a trap sent to the
management system. To further support high availability, the chassis may
operate without the hot-swappable fan tray for up to 10 minutes until the AVU is
replaced.
Table 1-2: PSU Requirements, Configurations with one NPU (excluding PSU
redundancy)
Number of AUs Minimum Required Number of PSUs
1 - 4 2
5 - 6 3