Configuration And Operation; Automatic Transfer Switch - Tripp-Lite PDUMH15AT Manuel Du Propriétaire

4. Configuration and Operation

4.1 Automatic Transfer Switch

When the Primary and Secondary inputs are both connected to Tripp Lite UPS Systems, the PDU
operates as an Automatic Transfer Switch, providing redundant input power for high availability
applications. Under normal operating conditions, the PDU will distribute power from the Primary
input source, switching to the Secondary input source under certain conditions. The PDU will switch
to the Primary source whenever it is Good according to the PDU input voltage definitions (see
below).
4.1A Preferred Configuration
The Automatic Transfer Switch function provides
increased availability when the Primary and
Secondary inputs of the PDU are connected to
separate Tripp Lite UPS Systems that are
connected to separate utility power sources.
For maximum availability, Tripp Lite
recommends using matching SmartOnline UPS
Systems with pure sine wave output for the
Primary and Secondary input power sources.
The automatic transfer switch function will be
compromised if the primary and secondary
inputs are connected to the same utility power
source.
Warning: DO NOT connect the primary input
to a line-interactive UPS, due to transfer
time issues, or to any source that does not
supply a pure sine wave. Such sources may
be used to power the secondary input.
4.1B Automatic Transfer Switch Source Selection
Upon power-up, the PDU looks for a source ≥85V. If it is unable to find a source ≥85V, it remains
off.
Input voltage definitions:
99V ≤ V
< 139V
in
75V ≤ V
< 99V
in
V < 75V
in
In normal operation (after power-up), if the selected source is no longer Good, the PDU will
attempt to switch to the other source, but only if the other source is Good. If the selected source
becomes Fair and the other source is not Good, the PDU will keep the loads connected to the
selected source until the selected source becomes Bad, at which point the loads will be
disconnected (note that the source selection doesn't change). After the loads are disconnected,
they remain disconnected until the selected source becomes ≥85V, or until the other source
becomes Good.
201011143 93-2857.indb 10
Good
Fair
Bad
Utility B
Facility Circuit
Secondary UPS
Secondary Input Cord
Critical Equipment
Loads
10
Utility A
Facility Circuit
Primary UPS
Primary Input Cord
PDUMH15ATNET
12/8/2010 2:03:54 PM