User's Manual

DRAFT 4
TB9400 Installation and Operation Manual Description 23
© Tait Electronics Limited September 2011
1.7.4 Power Management and Distribution
The PMU manages the supply of power to ensure uninterrupted operation
of the base station. A range of parameters is monitored and these can trigger
alarms that are sent to the reciter. Alarms can be monitored via the web
interface, and are also recorded in the reciter’s internal log file.
AC to DC
Changeover
When the PMU has an AC and a DC module, the base station can be
powered by either the AC (mains) or the DC (battery) supply. The base
station will default to the AC supply if both supplies are provided. If the AC
supply becomes unavailable, a seamless changeover from the AC to DC
supply takes place, providing that the battery voltage is above the configured
minimum. You can use a web browser to check whether the base station is
running on battery or mains power.
DC Operation When the base station is running off the DC supply and the battery voltage
falls below the configured minimum, the base station will enter battery
protection mode to protect the battery and base station equipment. The
standby power supply card maintains the power to the PMU microprocessor,
while the rest of the PMU is shut down. When the battery voltage rises to
the configured startup setting, power is resumed to the DC supply. Refer to
“PMU Operation on DC Input” on page 25 for more detailed information.
Auxiliary Power
Control
The output from the auxiliary power supply board can be used to power
other site equipment. The maximum output is 40 W.
Distribution Figure 1.8 shows how power is distributed to modules in the subrack. The
28 VDC output from the PMU is fed directly to the 100 W PA and 50 W
PA1, and to the other modules via the subrack interconnect board. Power
to the reciters and front panel is current-limited by self-resetting fuses on the
subrack board.
The AC converter has a series switch which breaks the phase input to the
converter. The DC input, however, has much higher current ratings. Its
switch does not disconnect power from the DC converter itself, but disables
the converter by switching off its control circuitry.
The outputs from both the AC and DC high power converters are added
together and fed to the modules via the high-current outputs. The auxiliary
output is also tapped off this summed output.