JADAC Power Support
3300 UPS Manual
Page 4 of 24
1.0
INTRODUCTION
1.1 General description
The Tower 3300 series of three phase double conversion Uninterruptible Power
Supplies (UPS) provide quiet, reliable and continuous power to an external load.
The load is protected against input transients and the output frequency is
controlled to within specified parameters. In the event of a power failure the UPS
will continue to maintain the load demands for a period dependant on the size of
the installed battery and the degree of loading.
In the unlikely event of UPS failure, the load will be automatically transferred
without any interruption directly onto the reserve mains supply. The unit can then
be connected into Manual Bypass mode for repairs to the unit (if required) without
disturbance to the load.
1.2 UPS building blocks
The Tower 3300 series has the following major building blocks:
1.2.1 Boost converter
The boost converter is able to utilize any of two sources to create a regulated,
filtered DC link which supplies the inverter.
State of the art power electronics is used to provide a near unity input power
factor while boosting its primary rectifier mains source.
If the incoming supply is lost, the boost converter boosts the battery.
When the primary source becomes available again, a linear
soft start
circuit
ensures that there is no
inrush
current drawn by the UPS.
1.2.2 Inverter
The inverter’s input is connected directly to the DC link with which it generates
three phase power to support the load.
The inverter uses Digital Signal Processors (DSP) to closely control and
monitor its output precisely – ensuring that the waveform remains perfectly
sinusoidal under all load conditions.
The frequency of the inverter is maintained in a phase locked condition with the
reserve supply frequency as long as it remains within the selectable tolerance
band. The inverter will run at its own oscillator derived frequency if the reserve
supply should fail.
1.2.3 Static transfer switch
The static switch is totally independent along with its own two independent
power supplies. The static switch will normally connect the load to the inverter
output. If the inverter becomes unavailable or goes out of tolerance, the static
switch (analog detection) will transfer the load to the reserve source without
interruption. The static switch also enables no break transfer/retransfers during
the maintenance bypass procedure.
1.2.4 Battery charger
The battery charger uses DSP control to regulate the temperature
compensated charging of the battery. The charger is equipped with both a
battery impedance test circuit and boost function. All the charger functions can
be controlled via the display.
