Alpha Technologies INEX 100A STS Module and MBS+PDU - Manual (Page 12)

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 2 of 26
1.3 Illustration of Operation
STS-100 is designed to avoid operational disruptions of critical loads. This automatic static transfer switch (STS)
automatically transfers critical loads from the primary AC power source to an alternative AC power source in the
event of interruption or abnormal conditions.
Figure 2–STS-100 operation illustrated
STS-100 transfers the critical load between power sources in less than 1/4 cycle upon loss of source. The fast
transfer enables further redundancy in distribution, adding level of availability, flexibility and reliability to our
customer’s power infrastructure.
1.4 STS Operating Principles
MBS Status Schematic operating principle of STS Description
Mains
Bypass
(P1)
Mains
Inverter
Load
Backfeed Relay
Bypass Relay
MBS Main Contact1
MBS Main Contact2
SCR1
SCR2
Mains Bypass:
Load is powered through the
MBS by Mains AC
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
Alternative AC Source
(UPS, generator, utility)
Inverter Output Voltage
STS Module
Sine Wave Output
Load
Communication Line
Power Line