Liebert SmartSwitchTM operation manual Description of SmartSwitch Operation, Status Indicators

3.0OPERATING INSTRUCTIONS

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.

3.1Description 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.

3.2Status 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.

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.

Operating Instructions 11