System information

GRAVITAS SABRE SERIES
INSTALLATION &OPERATING MANUAL
Manual No. SABRE-4 Page 13 11/27/07 sabre-man
MBS Status Schematic operation principle of STS Description
Normal
Operation (P3)
Mains
Inverter
Load
Backfeed Relay
Bypass Relay
MBS Main Contact1
MBS Main Contact2
SCR1
SCR2
Normal Operation(NORM)
Mains priority:
 Mains AC powers the
load through the static
switch
 MBS can be switched
from P3 to P2 and P4
position
 SCR2 open, SCR1 and
Back-feed Relay closed
 When the mains voltage
or frequency is abnormal,
and the inverter is normal,
the STS transfers to
on-line mode
 When SCR2 is short, the
STS will keep the off-line
mode
Normal
Operation (P3)
Mains
Inverter
Load
Backfeed Relay
Bypass Relay
MBS Main Contact1
MBS Main Contact2
SCR1
SCR2
Normal Operation(NORM)
Inverter priority:
 Inverters power the load
through the STS
 MBS can be switched
from P3 to P2 and P4
position
 SCR1 open, SCR2 and
Back-feed Relay closed
 When the Inverter’s
voltage or frequency is
abnormal, and the mains
is normal, the STS
transfers to off-line mode
 When SCR1 is short, the
STS will keep the
on-line mode, and the
Back-feed relay will
open