Type Of Detection Of Ac Input Loss (Ups); Limiting The Ac Input Current "Input Limit - Xtender XTS 900-12 User Manual

7.2.1 Type of detection of AC input loss (UPS)

When the Xtender is connected to the public grid or to a generator supplying stable and clean AC
voltage, the type of detection of input loss {1552} can be selected to "fast". In this mode, perturbation
or lack of voltage of less than one millisecond can be detected, switching the unit in inverter mode
immediately. This mode guarantees a zero or maximum of 15ms transfer time.
This mode should not be used in presence of highly disturbed utility grid or with a low power generator
or a generator supplying a poor quality voltage. In that case, the parameter {1552} will be set on
"tolerant". In the XTS model, this can be selected by positioning the UPS slide switch (20) in "off"
position. The tolerance of this mode is adjustable with the parameter {1510} if required.
The "tolerant" UPS mode insure an interruption time of max. 20 milliseconds.
In rare cases, due to the low quality of the source, and if the transfer relay switches too frequently, it is
possible to further reduce the sensitivity of detection AC input loss by changing the parameter {1552}
to "slow" via remote control RCC-02/03. In this case, the interruption of power will be 40ms max.
If the Xtender is connected to a generator, this must have a power at least equal to half of
the power of the Xtender(s) to which it is connected.

7.2.2 Limiting the AC input current "Input limit"

7.2.2.1 Principle
In order to best use the resources available at the input (depending on the generator size or the grid
output) and to protect the source from overload, it is possible to adjust the limit of the input current
with the parameter {1107}.
The Xtender will automatically distribute the available power to the charger and the user and supply
the balance of power if the load demand exceeds the fixed limit thanks to the current assistance
function "smart boost".
Due to the current assistance feature, the battery can be fully discharged despite the
presence of the grid or the generator! The average power consumed by the user must not
exceed the power of the source, at the risk of discharging the battery.
This system proves to be a decisive advantage particularly in all mobile systems (boats, leisure
vehicles and service vehicles) that are frequently connected to sources with a limited value such as
a portable or camping power supply. Despite a limited source, all the greater power applications
downstream of the Xtender remain functional.
Despite a limited source, all loads connected downstream the Xtender remain functional!
The system will reduce automatically the charging current– from its target value {1138} to 0 –
according to the current used at the output and the maximum current available at the input set by
the parameter {1107}. The greater the current at the output, the more the part of the current at the
input assigned to charging the battery is reduced. If the current exceeds the limit {1107}, the Xtender
will supply the balance current from the battery.
The wiring of the system (cable gauge) must take into account this particular function which allow
to have the sum of the current supplied by the inverter plus the current supplied by the source,
I.e. If the system have a 5kW source (22A) and a 5 kW Xtender, the available power at the output is
10kW! In this example, the wire gauge must be chosen for 45A.
7.2.2.2 Exceeding input limit current
If, despite the decrease in current from the charger and using the source current assistance the limit
is exceeded, the transfer relay will remain activated and the source may then be overloaded,
causing the opening of the protective device upstream (H).
Exceeding the limit may be prohibited by the parameter {1436}. In this case, if the current exceeds
the limit {1107}, the transfer relay will open and the user then powered exclusively by the inverter, as
long as the output current exceeds the current limit input. If the input current limit is exceeded due
to a short circuit downstream, the transfer relay will remain activated and the protective device
upstream of the Xtender (H) will trip.
7.2.2.3 Second value of input current limit
A second value of the input limit, to be activated by the remote entry (see sect. 7.7 - p. 31), is
programmable by the parameters {1566} (use a different value for the maximum current of the AC
source) and {1567} (second maximum current of the AC source).
User manual V4.6.0
Studer Innotec SA
Xtender
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