User's Manual

108 Connection TB8100 Installation and Operation Manual

7.2.3 Auxiliary DC Power

PMU Auxiliary DC

Output

The PMU can provide an auxiliary DC output when it is fitted with the

optional auxiliary power supply board. This board is available with an

output of 13.65VDC, 27.3VDC, or 54.6VDC (depending on the model),

and is current limited to 3A, 1.5A or 750mA respectively. This optional

power supply is available on the auxiliary DC output connector

b on the

rear panel. DC from this output can be supplied to the +AUX_V pin on

the system interface connector

c on the reciter via the auxiliary DC input

connector

d on the system interface board (see “Reciter Auxiliary DC

Input from PMU” below). The auxiliary DC power cables

e are described

in “Auxiliary DC Power Supply Connections” on page 110.

The auxiliary power supply is configured with the Service Kit (Configure >

Base Station > Miscellaneous > Power configuration > Auxiliary power

control). Its operation can be controlled by Task Manager statements, for

example:

IF Digital input 01 active THEN Enable auxiliary supply.

Refer to the Service Kit documentation for more details.

We do not recommend connecting two or more auxiliary power supply

boards in parallel to increase the current supply to external equipment. In

this situation, the auxiliary board with the highest voltage will try to supply

all the current required, until it goes into current limit and the voltage

reduces to the level where another board will begin to supply power.

Running an auxiliary board continuously in current limit will reduce its life

span and reliability. Also, if one auxiliary board fails or is switched off when

a base station is powered down for some reason, the remaining auxiliary

boards will be unable to supply the required current and will go into current

limit, possibly causing the external equipment to shut down.

It is, however, acceptable to connect two or more auxiliary power supply

boards in parallel (e.g. for redundancy), as long as the current consumption

of the external equipment is less than the rating of one board. This means

that, even if only one auxiliary board is functioning, it will still be able to

supply the current requirements of the external equipment.

Figure 7.10 Auxiliary DC power supply connections