inform PDSP 33010, Installation And Operating Manual

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5.2. Normal Operation
Energy is drawn from the mains input.
Loads are fed via the rectifier and the inverter. The AC voltage at the input is converted to a DC
voltage by the rectifier. The inverter converts this DC voltage to an AC voltage with a stable
sinusoidal waveform, amplitude and frequency.
Output voltage is sinusoidal and has a regulated amplitude and frequency. It is independent from
the input voltage.
The inverter is synchronized in frequency with the bypass mains input to enable load transfer to the
bypass supply without any interruption, in case of an overload or inverter failure.
Voltage and frequency of the mains input shall be in their tolerance limits, and both the rectifier
and the inverter shall be enabled for the UPS to operate in this mode.
When the upper provisions are met, the UPS works in normal mode in the following conditions:

If the inverter priority is selected.

If the bypass priority is selected but bypass is disabled or frequency/waveform/rms value of
bypass mains voltage is not in acceptable limits.
Mains Limits for Normal Operation
Frequency and rms value of the mains input voltage has to be between acceptable limits for the
UPS to operate in normal mode.
Lower limit of the voltage depends on how much the UPS is loaded and it decreases as the load
decreases until it reaches 80 V phase-neutral.
Frequency lower and upper limits and voltage upper limit are fixed.
Voltage and frequency ranges for normal operation are given in the “technical specifications”
section of the manual.
This feature lessens the need to use the batteries. Thus, it increases the battery life and continuity
of the load power.
Electronic Short Circuit Protection
The UPS attempts to force the thermal/magnetic protection devices between the output terminals
and the short circuited load to open, by supplying current to the short circuited load for a limited
duration. The UPS shall be working in battery or normal mode, for this feature to work.
To enable the short circuit protection feature of the UPS, each load shall be fed over a
separate circuit breaker chosen according to the load current. This may provide quick
disconnection of the short circuited load and operation continuity of the other loads. To
obtain maximum protection, the rating of each individual load circuit breaker shall have the
minimum value, which is enough to carry the full load current continuously.
If the protection device fails to open the circuit in a limited time, the UPS stops feeding current to
the output. “VSECFLR” message is shown on the upper left of the LCD.