System information

GRAVITAS SABRE SERIES
INSTALLATION &OPERATING MANUAL
Manual No. SABRE-4 Page 12 11/27/07 sabre-man
1.2.1.6 Operation principal of STS
The operation of the STS at each valid state is described below:
MBS Status Schematic operation principle of STS Description
Mains Bypass
(P1)
0DL QV
,QYHUWHU
/RDG
%DFNI HHG 5HO D\
%\SDVV 5HO D\
0%60DL Q&RQWDFW
0%60DL Q&RQWDFW
6&5
6&5
Mains Bypass(MBP):
 Load is powered through the
MBS by the Mains AC
 STS does not provide any
load power, and can be
removed from the system
 STS can be removed from the
system
 MBS can only be switched
from P1 to P2 position
 SCR2 open, SCR1 and
Back-feed Relay closed
Inverter
Maintenance
(P2)
0DL QV
,QYHUWHU
/RDG
%DFNIHHG 5HO D\
%\SDVV5HO D\
0%6 0DL Q&RQWDFW
0%6 0DL Q&RQWDFW
6&5
6&5
Inverter Maintenance(MSS):
 Mains AC powers the load
through the static switch
 Inverters are on, but do not
provide any load power
 Inverters can be removed
from the system, but the
static switch cannot
 MBS can be switched from
P2 to P1 and P3 position
 SCR2 open, SCR1 and
Back-feed Relay closed
 When SCR2 is short, the STS
will stay in off-line mode