Description Of The Main Functions; Inverter; Automatic Load Detection (Load Search); Transfer Relay - Xtender XTS 900-12 User Manual

Studer Innotec SA
Xtender
7

DESCRIPTION OF THE MAIN FUNCTIONS

7.1 I
NVERTER
The Xtender is equipped with a high-performance inverter, which supplies a perfect and very precise
sine wave. Any unit designed for the 230 V/50 Hz electrical grid (or 120V/60Hz for model XTx-xxxx-01)
may connect to it without any problem, up to the rated power out of your Xtender. The inverter is
protected against overloads and short-circuits.
Thanks to the largely over-dimensioned performance level, loads of up to three times greater than
the Xtender's rated output can be faultlessly supplied for short (3 sec) periods of use, thus allowing
motors to be started up without any problem.
When the Xtender is operating the LED "ON" (43) is glowing.
When the Xtender is in inverter mode, the LED "AC-Out" (46) is glowing. If it flashes, the inverter is in
"load search" mode (see following sect. "Automatic load detection").

7.1.1 Automatic load detection (load search)

In order to save battery energy, the Xtender inverter stops and automatically goes into load search
mode when the detected load is lower than the sensitivity set by the parameter {1187}. It
automatically goes back into operation when a power consumer greater than this value demands
it. The indicator (46) flashes if the inverter is in "load search" mode, which also indicates that the AC
voltage is present at the output in an intermittent form.
The detection threshold for the absence of loads can be adjusted according to the parameter range
{1187} by means of the RCC-02/-03 remote control. When the parameter is set to zero the inverter will
still operate even in the absence of any consumer.
In load search mode (standby), the system will thus consume minimal power from the battery (see
table of technical data p. 54).
7.2 T
RANSFER RELAY
The Xtender can be connected to an alternative power source such as a generator or public
network. When the voltage at the entry satisfies the voltage {1199 + 1470} and frequency {1505 -
1506} parameters, the transfer relay will be activated after a delay {1528}. This delay may be adjusted
(extended) to allow a fully stable status of the generator before transfer.
When the transfer relay is activated, the voltage present at the input of the Xtender is available at
the output for the consumers connected. At the same time the battery charger goes into operation.
When the transfer relay of the Xtender is active, the voltage at the output of the Xtender is
equivalent to that which is present at the input and cannot be influenced or improved by
the Xtender. The consumers are supplied by the source present at the "AC-IN" input via the

transfer relay.

The maximum current of the transfer relay is 50 A for XTH and XTM model. It is of 16A in XTS model.
The sharing of energy between consumers and the battery charger is adjusted automatically (see
sect. 7.2.2– p. 27). The transfer relay will be deactivated when the input voltage no longer satisfies
the parameter {1199} or {1432} min. and max. voltage and frequency at the input or when the current
limit {1107} is exceeded, if the exceeding of this limit is prohibited {1436}. It then passes immediately
into inverter mode. In this case the loads are supplied exclusively by the battery via the inverter (see
sect. 7.2.2.4 – p. 28). This switching always takes place automatically.
The presence of increased dynamic loads (such as pneumatic angle grinders, etc.) may lead to an
undesirable opening of the transfer relay due to the weakness of the source. To this case, a delay in
the opening of the transfer relay can be adjusted with the parameter {1198}.
When the generator stops, the change from transfer mode to inverter mode normally takes place
without any interruption of the output voltage. The interruption will be 20ms in case of input voltage
sudden disappearing when the type of detection of input loss (UPS) {1552} is selected to "tolerant".
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