OnLine Power Telecommunication - Manual (Page 24)

OnLine Power
1-9
REV A
1-9 THEORY OF OPERATION
• System schematic diagram shows the power path through PBC-II. See Illustration 1-5 for 120 Volt
unit, Illustration 1-6 for 230V unit, Illustration 1-7 for optional 120V Adjunct Battery Cabinet, and
Illustration 1-8 for optional 230V Adjunct Battery Cabinet. There is an option for extra 4 hours
battery run time. The optional Adjunct Battery Cabinet provides an additional 4 hours of battery
backup time. The main cabinet provides 4 hours of battery backup time, as a standard feature.
• Input Stage
Utility power enters the system through input circuit breaker from terminal block TB1-1, 1-2, and 1-3.
The capacitors C2, C3, and C4 and EMI filter (A3) are for EMC requirements of FCC, 47CFR, Part
15, Subpart B.
Surge suppressor after the CB1 protect the unit for impulse class “B” requirement.
• Power Conditions Stage.
The input power is applied to the power PCBD assy through CN3L and CN3N and also is applied to
the Battery charger PCBD (A6-A). The power PCBD assy (A1-A) with control PCBD assy (A1-B)
monitors the input voltage at all the time for the input voltage range specifications such as 85 Volt -
130 Volt for 120 Volt unit and 180 V - 264 V for 230 Volt unit.
When the input voltage is within the range specification, the input power will support the critical load.
The output voltage to the critical load will be same as the input voltage and will vary according to the
input voltage variation. It is called “off-line technology” U.P.S.
When the input voltage range is out of the range specification, then microprocessor controlled logic
(A1-B) initiates the immediate transferring to the battery and the inverter will support the critical load
now from battery power without any output power interruption. The transfer time is within 4.3
milliseconds - 10 milliseconds with 100% load condition. If the load is less than 100% load, the
transfer time is less. When any alarms such as overtemperature or overcurrent, over voltage or
under voltage occur while the inverter supplies the power to critical load from the battery, the
inverter will shut-off and try to by-pass to the input power source. (See Appendix E at the end.)