Universal Bypass Switch Unit
UNB
Operation Manual
UNB2357E / Page 21 (34)
7. Synchronisation
The STATIC BYPASS SWITCH SBS is designed for two
internal synchronisation procedures. The first one being the
synchronisation between the internal fixed-frequency of the
SBS and the attached inverter (as well as for several
inverters in case of parallel operation mode) and additionally
the synchronisation of SBS for the frequency of the
substitute mains. Both synchronisation-processes will be
shown via the LED „synchronisation “.
Synchronisation-process for inverter preference with
disconnected substitution-mains:
If the SBS switches on, load immediately switches at
substitute-source (even if not existing)
SBS feeds own-frequency in synchronous-bus (SYNC-
BUS) a (50 Hz - signal, amplitude approximately 15V
between SYNC-BUS and SYNC-GND)
SBS registers via signal-bus as master (square-signal
approximately 15V between SBS-SYNC and SYNC-GND)
After synchronisation with the inverter indication LED
shows synchronisation in progress
SBS switches the consumer load to inverter output; LED
„load at inverter“ signal.
Connection of the substitute-mains
After a postponement from approximately 5 seconds
(SBS waits for a stabilised substitute mains ) the SBS
tries to synchronise on the substitute source frequency.
During this action the LED “Synchronisation“ signal is off.
After the successful synchronisation of the SBS with the
substitute source, all units work with the frequency of the
substitute-source (SYNC-BUS carries substitute-
frequency) and the LED „synchronisation “ lights;
according to the difference of the Monitoring signal
(internal PLL) to the actual sine-wave of the voltage the
synchronisation requires up to 30 seconds.
Synchronisation-process for inverter preference operation
with connected substitute-mains:
SBS switches on, load is immediately connected to the
substitute-source.
SBS registers via the signal-bus as masters (a square
signal approx. 15V between SBS-SYNC and SYNC-GND)
After a postponement of approx. 5 seconds ( SBS waits
for stabilised substitute mains.) then it synchronises on
the frequency of the substitute source; during this
