Static Power iSTS W - Synchronism; Start-Up

iSTS W
– User Manual
Page 9
3
.4 Synchronism
The
smoothest change-over occurs when the supplies are in synchronism, so it is best to make sure the
input
supplies
are in synchronism. Some equipment (like transformers) may saturate when a transfer occurs when
not
in
synchronism. This causes large currents to flow into the load which could cause damage to the
transformer,
trip
protective devices or blow fuses.
The
iSTS is configured to optimize the transfers. Manual transfers by default have uninterrupted
transfers,
however,
at greater phase displacements (up to ±180 degrees) a break of up to 12ms is inserted.
3
.5 Start-up
NOTE
: Due to the nature of SCRs (silicon controlled rectifiers) some load of around 0.5A is required for
correct
operation
. Before testing the operation of this iSTS, make sure this load is applied to the output.
1. Ensure that your two input sources are within the tolerances and in synchronism..
2. Apply power to both input sources. There will be a short 15 second start-up period, after which the
iSTS
will begin powering your load.
3. you will be prompted to enter the date and time. We strongly encourage the setting of the date and
time
so that real time event correlation can be undertaken. The Real Time Clock is backed up by a
rechargeable
coin cell battery. If the battery is flat at the time of commissioning it may take several days to re-charge.
4. The ALARM should not be active. If it is check the following conditions that may be active:
- ON Supply 1 when priority is Supply 2
- ON Supply 2 when priority is Supply 1
- Supply 1 or Supply 2 are not in spec
- Override Switch is in position 1 or 2
- Supply 1 & 2 are not in synchronism
- The unit is too hot (thermal bi-metal switch on H.S. activated)
- There is / was an overcurrent/ overload / load fault condition