M/A-Com P5100 Series, Maintenance Manual

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DESCRIPTION
3.0 DESCRIPTION
The M/A-COM MASTR® II/III Base Station 12/24 Volt Power Supply provides up to
429 watts to power a MASTR II/III 800 or 900 MHz base station receiver, system
circuitry, and transmitter. The nominal 12 volt output is actually 13.0 VDC and provides
a maximum of 3 amperes to power the receiver and system circuitry. The nominal 24 volt
output is actually 26.0 VDC and provides a maximum of 15 amperes to power the
transmitter power amplifier.
The 60 Hz Model (19A149979P1) operates from a nominal 121 VAC, 60 Hz source. If a
208/220/240VAC, 60 Hz source is used, an external step-down transformer (similar to
19C307148P1) must be used with the ’979P1 supply. The 50 Hz model (19A149979P2)
provides the same output as the ’979P1 supply, but operates from a nominal 230 VAC,
50 Hz source. The output voltage will change a maximum of +1.6% for each +1.0%
change in the input line frequency. The 60 Hz model (19A149979P3) provides the same
output as the 979P1&P2 supplies, but operates from a nominal 220 VAC, 60 Hz source.
NOTE
A ferroresonant power supply is designed to work specifically at a given frequency.
The 60 Hz and 50 Hz supplies should be used at their nominal frequency
±
2 Hz.
The power supply step-down ferroresonant transformer provides excellent line voltage
regulation. For the rated input line voltage range ( ±20% for P1, ± 15% for P2), the
output voltage will not vary more than 2%. A ferroresonant power supply provides
inherently excellent line voltage surge protection, and fewer parts for high reliability. No
active semiconductor devices are used, which could reduce reliability.
The output voltages will vary depending on the load currents that the supply is being
asked to source. As the load current rises, the output voltage will drop. Typical output
voltages for various load currents are shown in Table 3-1.
Table 3-1: Typical Output Voltages
LOAD CURRENT CONDITIONS 12 V OUTPUT 24 V OUTPUT
TX AND RX SIMULTANEOUSLY (15 + 3 AMPS) ~13.0 VDC ~26.0 VDC
RX ONLY (0 + 3 AMPS) <15.8 VDC <29.0 VDC
NO LOAD (0 + 0 AMPS) <16.3 VDC <30.0 VDC
The operation and servicing of the power supply are completely accessible from the
front. The ON/OFF switch and all fuses are located on the front panel. The low profile
slot type fuse holders contain the primary fuse(s) F1 (F1 and F4 for P2), the high current
output fuse F2, and the low current output fuse F3. The primary fuse(s) protect the input
wiring to the ferroresonant transformer (one 10 amp fuse for P1, two 5 amp fuses for P2).
The output fuses F2 (20 amps) and F3 (5 amps) provide external overload protection.
The 60 Hz supply provides a courtesy dual AC receptacle. The primary line current fuse
(F1) also provides overcurrent protection for the dual receptacle. The 60 Hz supply draws
5 amps under nominal conditions and 7 amps under all conditions. Thus, the dual
courtesy receptacles are rated for 3 amps.
8 LBI-38551D