Specifications

88
Static Transfer Switch (STS)
Sentry STS
Sentry STS is a static transfer switch
commonly used within power continuity
applications to improve resilience. The
system can be used in conjuction with
UPS or as separate standalone
devices.
OPERATING PRINCIPLE
Sentry STS adds a source of
redundancy to a critical installation and
automatically transfers the connected
load between two separate AC power
sources. The transfer can be automatic
when an input power supply fails
outside set tolerances or be manually
forced using the front panel keypad or
remotely via a communications
network.
PROTECTION AGAINST
POWER FAILURES
In the event that one of the two power
sources does not return to the
accepted tolerance values, the Sentry
STS will transfer the other loads over to
the second power source (this
happens instantly if the two sources
are in phase).
PROTECTION AGAINST
ENVIRONMENTAL DISTURBANCES
OVERLOADS AND LOAD FAULTS
In the event of an overload or fault
condition, the internal protection
system within the STS device can be
configured to disconnect power at
defined levels. In the extreme situation
of a downstream short circuit, Sentry
STS can disconnect the load to
prevent disruption.
CHARACTERISTICS
• Full protection of critical industrial
and IT applications against power
failures and faults on the load.
• Full microprocessor control which
guarantees:
- fast and safe transfer between
the power sources;
- monitoring of all parameters on
the LCD display;
- constant control of the SCRs;
- remote advanced diagnostics
(RS232 and TCP/IP).
• Redundant power circuits:
- power is supplied to the internal
logic by two separate and
independent power circuits that are
hot swappable so as to ensure no
break in the supply to the loads;
- in the event that the power supplied
by both sources fails, full system
operation is guaranteed by the Power
Supply Backup function that provides
backup power to the circuits from an
external, independent standby power
source.