Tait TN9275, Инструкция по установке и эксплуатации, Страница: 35 / 155

TB9400/TN9275 Installation and Operation
Description 35
© Tait International Limited May 2023
1.8.4 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
WebUI and reported via SNMP traps; they 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 startup voltage. 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 37 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 40W.
Distribution
Figure 1.8 shows how power is distributed to modules in the subrack. The
28VDC output from the PMU is fed directly to the PA in a single base
station, or directly to PA 1 in a dual base station, 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 that breaks the phase input to the
converter. In contrast, the DC input 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.