Alpha Technologies INEX 100A STS Module and MBS+PDU - Manual (Page 13)

Argus Technologies Ltd. 019-061-C0 Rev A WC
Printed in Canada. © 2009 Argus Technologies Ltd. ARGUS is a registered trademark of Argus Technologies Ltd. All Rights Reserved. Page 3 of 26
Inverter
Maintenance
(P2)
Mains
Inverter
Load
Backfeed Relay
Bypass Relay
MBS Main Contact1
MBS Main Contact2
SCR1
SCR2
Inverter Maintenance:
Mains AC powers the load
through the static switch
Inverters are on, but do not
provide any load power
Inverter can be removed from
the system, but the static
switch can not
MBS can be switched from P2
to P1 and P3 position
SCR2 open, SCR1 and Back-
feed Relay closed
When SCR2 short, the static
switch will keep the off-line
mode
Normal Operation:
Mains
Inverter
Load
Backfeed Relay
Bypass Relay
MBS Main Contact1
MBS Main Contact2
SCR1
SCR2
1. 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 main’s voltage or
frequency is abnormal, and the
inverter is normal, the static
switch should transfer 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
2. Inverter priority
Inverter powers the load
through the static switch
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 static
switch should transfer to off-
line mode
When SCR1 is short, the STS
will keep the on-line mode,
and the Back-feed relay will
open