System information

GRAVITAS SABRE SERIES
INSTALLATION &OPERATING MANUAL
Manual No. SABRE-4 Page 14 11/27/07 sabre-man
MBS Status Schematic operation principle of STS Description
Mains
Maintenance
(P4)
Mains
Inverter
Load
Backfeed Relay
Bypass Relay
MBS Main Contact1
MBS Main Contact2
SCR1
SCR2
Mains Maintenance(ISS):
 Inverters power the load
through the STS
 AC mains is
disconnected from the
system, and the STS
cannot be removed from
the system
 MBS can be switched
from P4 to P3 and P5
 Back-feed Relay and
SCR1 open, and SCR2
closed
Inverter Bypass
(P5)
Mains
Inverter
Load
Backfeed Relay
Bypass Relay
MBS Main Contact1
MBS Main Contact2
SCR1
SCR2
Inverter Bypass(IBP):
 Load is powered through
the MBS by the
inverters.
 The STS does not
provide any load power,
and it can be removed
from the system
 STS can be removed
from the system
 MBS can only be
switched from P5 to P4
position
 Back-feed Relay and
SCR1 open, and SCR2
closed
Figure 4 STS operation principle