OnLine Power
(6002-1646) REV.X8 2
systems, from electrical interference. The Fire Alarm Back-up UPS1481 protects these systems
from power problems associ ated with poor quality AC power i nc lu ding complete power Outages .
Electrical disturbances can c o me from practically anywher e: from the incoming power lines a nd
even from within a building. Out s i de electrical disturbances inc lu de lightning strikes, utility
switching, brown—outs, and ac c i dents. Electrical disturba nc es f ro m within a building can be
caused by load cycling (elevators, HVAC systems), fault conditions, welders, and ot h er
electrically noisy equipme nt . W het h er the electrical disturbances ar e generated outside or from
within the facility, the followin g p ower problems will occur:
The following describes t he ma jor bloc ks withi n the Fire Alar m Bac k-up U PS1481. Pleas e refe r
to Illustration. Block Diagra m for additional information.
Bypass Static Switch — The SCR solid state switch bypass es the complete UPS and provid es
utility input directly to the load i n c as e of p roblem with UPS. This switch als o s u pplies input
power to the load during the start u p. It is connected on the primary s ide of the optional output
isolation Transformer, when used. This switch maintains it’s s t at us o pposite of that of the output
SCR solid state switch.
Output Static Switch — This SCR solid state switch connects t he out put of the inverter (UPS)
to the load. It is connected on the p rimary side of the optional outp ut isolation transformer, when
used. This switch shuts—off in c ase of a problem or failure wit hin t h e UPS and transfers the
load directly to the utility input vi a bypass static switch. It maint ains it ’s s t at us o pposite to that of
bypass switch.
Power Board with IGBTs — The Power board is bolted onto the I G BT blocks that are mounted
on a heat sink. The complete he at sink assembly with IGBT and power board is replaceable as
one part. This assembly proc es s es a il the power, ie. input AC power co nv e rted to DC bus,
battery power boosted to DC bus a nd finally DC bus power converte d to output AC power using
PWM technology for smoot h A C Sinewave. The complete h eat s ink as s embly is easily
replaceable using only a scr e wdriver, in case of a catastrophic f ail ure, if required. This board
also has the housekeeping p o wer supplies and driver circuits for I G BTs. This board also
provides the landing place fo r all i nternal input, output, and DC c abl es as well as it monitors the
input-output current for contr ol a nd metering.
Control Board — The microprocessor with progra mmable logic controllers and on bo ard
memory is located on this boar d. It is mounted on the door and co m m u nicates, controls, and
monitors the power board via a ri bbon cable. This board also se ns es t he i nput AC and sends
the command to close/open t he i nput contactor, bypass static s witc h and output static switch.
This board also sends all the data t o the LCD display panel locate d o n the door. It also has
modem, AS400, RS232, and R S4 85 output capabilities.
LCD Display Pa ne l — T his f ront p anel provides all the metering d at a f or in put, output and
battery; alarm data and UPS st at us f or c ustomer use in a constantly ch an ging and updating, the
3 sets of the screens.