Function Of The Power Supply; Figure 13: Power Supply - Motorola ASTRO 25 GTR 8000 Manual

2.1.4

Function of the Power Supply

The power supply, with front-to-rear airflow, operates from either an AC or DC input and provides the
DC operating voltage for the base radio. However the power supply prioritizes an AC source (if
present) over a DC source.

Figure 13: Power Supply

NOTICE: If the power supply module is used for the Power Efficiency Package, the power
supply must be used in DC mode to obtain the 35 W standby power consumption performance.
When operating from an AC source (90 to 264 VAC, 47-63 Hz), the supply generates two DC output
voltages of 29 V with respect to output ground. The power supply automatically adjusts to AC input
ranges and supplies a steady output.
In AC mode, the power supply may provide a separate battery charger which can be used to maintain
the charge on a 48 VDC nominal system, positive or negative ground, if installed. The supply
generates two DC output voltages of 29 V with respect to output ground, when operating from a DC
source (43.2 VDC to 60 VDC maximum), positive or negative ground. This voltage limit includes
consideration of the battery charging "float voltage" associated with the intended supply system,
regardless of the marked power rating of the equipment. Whether in AC, Battery Revert, or DC Only
mode, at a voltage of 42 V or lower, the power supply shuts down to not damage any connected
battery bank. Once this condition occurs, the power supply starts only after the applied voltage
exceeds 45 V.
The battery charger is not usable when operating from a DC input power source. This DC source must
be located in the same building as the base radio, and it must meet the requirements of a SELV circuit.
The power supply contains several switching-type power supply circuits as follows:
• Power factor correction circuitry
• Battery charging circuitry
• Diagnostics and monitoring circuitry
The power supply controls its own continuously running fan, changing its speed to fast, or slow as
needed.
Chapter 2: GTR 8000 Base Radio Theory of Operation
MN003286A01-E
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