Motorola Solutions Inc. 89FC4825 Manuale Utente

 
Functional Description / Operation of Modules (Draft) 
 

The Power Supply is described in this section.  The information provided is sufficient to give service personnel a 

functional understanding of the module, allowing maintenance and troubleshooting to the module level.  (Refer to 
the service manual for Maintenance and Disassembly/Reassembly Procedures for detailed removal or installation 

procedures for all modules in the station.) 

The Power Supply has built in power factor correction and includes a connection for battery backup that also 

serves as the DC input when the supply is used in DC only input mode. 

The Power Supply accepts an AC or a DC input (AC input = 85 to 264 VAC, 50/60 Hz, DC input = 21.6 to 32 VDC) 
and generates three output DC voltages to power the station modules: +28.6 VDC, +14.2 VDC and +5.1 VDC. 

Note: When used in DC input mode, the 28.6 VDC output equals the DC input within 0 to -0.5 VDC. 

Note: An external 24V (nominal) battery system is required to support the battery backup feature so that when the 

AC power fails, the BR can be powered from a DC battery source if it is connected to the PS.  This results in 

uninterrupted radio service (for as long as battery power can be provided).  As the PS does not have a battery 
charging function, when the AC power is restored, an external charger is required to recharge the battery. 

The power supply is a high-frequency switched mode design, all contained in a metal heat-sink, and mounted on 

the left-hand side of the station.  The design provides for output over-voltage/overcurrent protection. 

The AC input connection is made at the rear of the station via an IEC-type connector keyed to accept only high 

temperature type mating connectors.  Also provided is a Battery Backup connection (see DC mode above).  Power 
supply cooling, when necessary, is provided by an external fan (located near the middle of the heatsink) which 

provides forced air across the power supply heatsink fins. 

The following shows the electrical performance specifications for the power supply. 

 

Power Supply Module AC Performance Specification: 

 

Input Voltage Range 

85 VAC to 264 VAC 

Input Frequency Range 

47–63 Hz 

Steady State Output Voltage 

28.6 V @ 13 A, 

14.2 V @ 8 A,  

5.1 V @ 2 A 

Output Power (Rated) 

500 W 

Output Ripple: 

+28.6 VDC 
+14.2 VDC 

+5.1 VDC 

 

50 mV p-p, @ 25°C (77°F) 
50 mV p-p, @ 25°C (77°F) 

100 mV p-p, @ 25°C (77°F) 

 

Power Supply Module DC Performance Specification: 

 

Input Voltage Range 

21.6 - 32 VDC 

Steady State Output Voltage 

28.6 V @ 13 A, Input Voltage Dependent 

14.2 V @ 8 A, Regulated 

5.1 V @ 2 A, Regulated 

Output Power (Rated) 

500 W 

Output Ripple: 
+28.6 VDC 

+14.2 VDC 

+5.1 VDC 

 
Input Voltage Dependent, 0-0.5V below input 

50 mV p-p, @ 25°C (77°F) 

100 mV p-p, @ 25°C (77°F)