- 3 -
2.2 Features
- True On-line pure sine wave
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Microprocessor controller
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Stable output frequency (Crystal control)
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Over current and short circuit protection
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Built-in output isolation transformer
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Load safe battery test (available in NBP S-series only)
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EMI/RFI and power line noise protection
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Automatic bypass overload protection
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Automatic bypass transfer switch (zero transfer time)
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DC start (AC start without battery (option))
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Manual self-test
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RS-232 communication port
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Sealed lead acid maintenance free battery
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LED indicator and LCD display
2.3 UPS Operation
2.3.1 When utility power and loads are normal
Above diagram shows how UPS works when utility power (AC line) is normal and UPS has less
than 100% load. UPS converts utility power from alternative current (AC) to direct current (DC) at
RECTIFIER. Some of the DC power flow to charge battery to be backup power and the rest flow
directly to INVERTER to invert power to high quality and stable AC power. Then, supply to load.
2.3.2 When utility power is normal but overload.
