Liebert SmartSwitchTM - Manual (Page 15)

Operating Instructions 11
3.0 O
PERATING
I
NSTRUCTIONS
3.1 Description of SmartSwitch Operation
The SmartSwitch™ is an automatic transfer switch designed to provide fast automatic transfers
between two independent, synchronous AC power sources to provide continuity of AC power to
critical equipment, such as information technology equipment. One of the two AC inputs is desig-
nated as the “preferred” source to which the SmartSwitch will connect the load as long as the des-
ignated input source is within acceptable voltage limits. If the preferred source falls outside the
acceptable limits, the SmartSwitch is designed to transfer the output load to the other “alternate”
input source, as long as the alternate source is within acceptable voltage limits and is synchro-
nized with the preferred source within the selected phase synchronization window. The Smart-
Switch provides fast, break-before-make transfers to prevent interconnection of the two sources,
even under faulted source conditions. The maximum sense and transfer times are within the tol-
erance of the IEEE Standard 446 susceptibility curve for information technology equipment to
allow uninterrupted load equipment operation. To prevent the transfer of a output overload or
fault condition, the SmartSwitch automatically disables transfers to the alternate source if the
output current exceeds preset limits.
The SmartSwitch™ consists of two modules, a fixed module containing the input and output con-
nections and bypass/transfer control switch, and a plug-in, removable electronics/switching mod-
ule. The bypass/transfer control switch is located behind a keylocked, hinged access cover to
restrict access to qualified or designated operators. The plug-in module likewise contains key-
locked latches to prevent unauthorized removal of the module. The SmartSwitch is designed to
allow replacement of the removable electronics/switching module without having to de-energize
the load equipment. See the bypass, transfer control, and module replacement instructions for
more information.
3.2 Status Indicators
The SmartSwitch contains seven long-life, status indicators located on the removable electronics
module to indicate the unit and source status. See Table 2 for a listing of the status indicators
and their definitions. The status indicators are active as long as the removable module is in place
and at least one of the two input sources is energized.
NOTE
Read the entire operating instructions section before placing the
SmartSwitch into operation.
NOTE
For continued protection against a source failure, periodic testing of the
SmartSwitch is recommended. For manual testing, see the transfer control
instructions.
Table 2 SmartSwitch Status Indicators
Indicator Description
ON PREFERRED SOURCE The output load is connected to the preferred source.
ON ALTERNATE SOURCE The output load is connected to the alternate source.
PREFERRED SOURCE OK All phases of the preferred source are within voltage limits.
ALTERNATE SOURCE OK All phases of the alternate source are within voltage limits.
TRANSFER INHIBITED Automatic transfer is inhibited. Reasons for transfer (or retransfer) inhibit
include both sources are not available, sources are not synchronized, or the
output load has exceeded the preset limit.
SUMMARY ALARM The SmartSwitch has detected a fault condition. If both sources are available
and synchronized, then the alarm may indicate a SmartSwitch failure.
ON BYPASS The bypass/transfer switch is in the bypass position.
S1 PREFERRED* Source 1 is selected as the preferred source.
S2 PREFERRED* Source 2 is selected as the preferred source.
*These LED indicators are only provided on the rackmount units.