Automatic Transfer Mode :
The STS constantly monitors the voltage and frequency of both input sources.
When the two sources are in
synchronisation
if the source powering the load goes out of tolerance (with
respect to voltage or frequency), the STS automatically transfers the load onto the alternative power source in
less than 5msec.
If the two sources are not in synchronisation
,
the transfer may take place in one of three different ways which
can be configured by the user via the
OPTIONS MENU
:
1) NSYNC.TR:0-curr. (zero current mode):
the transfer takes place when the output current goes to
zero (method used for synchronised switching) with a maximum transfer time of approx. 10msec.
2) NSYNC.TR:DELAY (delay time mode):
the transfer takes place after a delay that can be configured
by the user, (default value is 24 msec) during this period the load is not powered
3) NSYNC.TR:DISABLE (disable mode):
the transfer is inhibited for asynchronous sources
Re-Transfer Mode :
SYNCHRONISED RE-TRANSFER:
If the user selects one of the two sources as the preferred source, the selected source is shown by the
corresponding LED (L1 or L2 on the mimic display panel). The preferred source selected powers the load
continuously provided it remains within the tolerance range.
A failure in the preferred source causes the load to be transferred onto the alternative power source.
The re-transfer takes place in “
0-curr
“(zero current mode), this is when the load current goes to zero.
UN-SYNCHRONISED RE-TRANSFER:
If the two sources are not synchronised, the user can configure the method used for the re-transfer onto the
preferred source. This can be selected via the
OPTIONS MENU
:
1) RET.MOD:0-curr. (zero current mode):
re-transfer takes place in any case when the load current
goes to zero
2) RET.MOD:WAIT SYNC (wait synchron mode):
the STS waits until the two sources are in sync
before effecting the re-transfer. The two sources have to remain in sync for 30 msec. at least
3) RET.MOD:DELAY (delay time mode):
the re-transfer takes place after a delay that can be set by the
user (default value is 24 msec.) during this period the load is not powered
4) RET.MOD:SWIFT (Swift mode):
the STS retransfers the load to the preferred source when the
current of the two sources goes to zero at the same time; if this does not occur, the load is not re-
transferred
The number of times the load is switched between the two sources can be limited by inhibiting the re-transfer
onto the preferred source. The re-transfer option can be enabled or disabled from the menu
OPTIONS MENU /
R-XFER
: (ON or OFF).
When the values of the preferred source return to normal condition, the load is automatically re-transferred
onto the preferred source after a delay (re-transfer delay time default value 16 sec.) from 16 to 127 sec. which
can be configured by the user from the
OPTIONS MENU
. (
D.R-XFER
parameter
)
31
Summary of Contents for STS 1000A 3 Pole
Page 1: ...Static Transfer Switch 100 150 200 250 300 400 600 800 1000 A 3 POLE 4 POLE User Manual...
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Page 47: ...47 AGKK7306 10 2020...
