System information

GRAVITAS SABRE SERIES
INSTALLATION &OPERATING MANUAL
Manual No. SABRE-4 Page 19 11/27/07 sabre-man
1.2.1.10 SCR short protection/Back-feed protection
1.2.1.10.1 On-line mode
The SCR1 on the mains side will be detected when the STS operates in on-line mode. If SCR1 is short, the back-feed
relay will be open, and the system continues to power the load from the inverters. At this time, “SCR1 short alarm”
will be sent to the controller via the CAN bus.
M a ins
Inve rter
Loa d
B ackfeed R ela y
B ypass
R ela y
S C R 1
S C R 2
M a ins
Inve rter
Loa d
B ackfeed R ela y
B ypass
R ela y
S C R 1
S C R 2
Backfeed relay
closed
SCR1 is normal
Backfeed relay open
SCR1
short
Inverter power the load
Inverter power the load
Figure 8 SCR1 short in on-line mode