User manual

In equipments with separate bypass line, an isolation transformer must be placed at any of both
input power supply mains of the UPS (rectifier input or static bypass), in order to avoid the direct
connection of the neutral of both mains through the internal wiring of the equipment.
Fig. 18. UPS-B block diagram with operating flows.
3-3. Operating principle
This online UPS is a double conversion system AC/DC, DC/AC with a sine wave output that gives safe
protection in extreme conditions of power supply (variations in voltage, frequency, electrical noises,
blackout and micro cuts, etc…). Whatever the kind of load that has to be protected, these devices are
prepared to assure quality and continuity in the electrical supply.
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The operation is basically as follows:
Rectifier, an IGBT three phase rectifier, converts the AC voltage into DC by absorbing a pure sine wave
current (THD <2%), and charging batteries at constant current / voltage.
The batteries supply the power needed by the inverter in the event of mains failure
The Inverter deals with transforming the voltage of the DC bus into AC by providing a sine-wave,
alternating output stabilized in voltage and frequency suitable for supplying the loads connected on
the output.
The basic double conversion structure is complemented by two new functional blocks, the static
bypass commuter switch and the manual bypass commuter switch
The static bypass commuter switch connects the output load directly to the bypass network in
special circumstances such as overloading or overheating and reconnects it to the Inverter when
normal conditions are restored
The UPS-B version has separate lines for the Inverter and bypass blocks, thus increasing the safety
of the installation, as it allows the use of a second mains (generator unit, other company, etc…)
The manual bypass commuter switch isolates the UPS from the mains and from the loads connected
on the output, so that maintenance operations may be performed in the UPS without any need to
interrupt the supply to the loads.