IBM Fire Alarm Back-up UPS1481 UNIT - Manual (Page 27)

OnLine Power
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9. Optional Output Isolation Transformer (TI) — The transformer performs a number of
critical functions. First, it provides excellent common mode and normal mode noise
isolation of the load from the input or inverter power. Secondly, it provides voltage
transformation and tight regulation of the output voltage while the Fire Alarm Back-up
UPS1481 is operating from its internal inverter or directly from utility via bypass circuitry.
10. lnverter Test Switch (SW2) — This switch is a manually operated switch which tests the
Fire Alarm Back-up UPS1481 and the batteries for proper operation. When the Fire Alarm
Back-up UPS1481 is running and Switch SW2 is pushed and held in, the Fire Alarm Back-
up UPS1481 will automatically transfer to battery operation. The Fire Alarm Back-up
UPS1481 will continue to run on batteries until the switch is released back to the “normal”
position (Switch is a momentary switch). When the switch is released, the Fire Alarm
Back-up UPS1481 returns to normal operation (provided input power is present).
11. Control
Transformer (T2) — This transformer with fuse (Fl), provides (internal
housekeeping) power supply as well as 120 VAC for the coil of the input contactor. The
primary of this transformer has various taps that needs to be matched with the various
input voltages.
12. Fan Transformer (T3) — This transformer with fuse (F2) provides 120 VAC to the fan(s)
for various output voltages that are matched at its primary taps.