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6. Configuration and Operation
6.1.2 Automatic Transfer Switch Source Selection
The ATS will power up and supply output if at least one of the inputs is greater than the minimum
startup voltage. In normal operation, when both sources are of equal quality (“fair” or “good”), the
unit will select the preferred source according to the preferred source selection setting (Refer to
section
5.1 Navigating Config Menus and Submenus
). If the currently selected source degrades
to a quality less than the currently unselected source, the unit will transfer to the better quality
source. If the currently unselected source improves in quality greater than the currently selected
source, the unit will transfer to the better quality source.
Note:
In the event of a voltage loss on one of the 3-phase input conductors, the loads connected to the failed
phase conductor will transfer to the alternate source. The remaining load will follow and transfer to the alternate
source within 1 second. If both sources have mixed levels of stability in their phases, the ATS will select the
source of each phase on the basis of best available. If one of the sources has all 3 phases return to “good”
quality, the unit will then transfer all phases to that source.
Input Voltage Ranges
Nominal Voltage
208V
Minimum Startup Voltage
163V
Good Voltage Range
172-241V
Fair Voltage Range
144-171V
Bad Voltage Range
0-143V
6.1.3 Quick Test
After installing the ATS/power strip and connecting equipment, you
may test the Automatic Transfer Switch function by temporarily
disabling the preferred AC input (default is Source A). The ATS will
then switch from the preferred input to the alternate input. When
the preferred input resumes supplying power, the ATS will switch
back to the preferred input.
Note:
The two inputs must be connected to separate sources of utility
power. The automatic transfer switch function will be compromised if the
two inputs are connected to the same power source. Do not perform a test
with equipment that must remain in productive operation. Any test
procedure must prepare for the contingency that the equipment may lose
power. Do not test the ATS by detaching power cords which are connected
to live power sources, as this eliminates the connection to ground and
places your equipment at risk.
Preferred Source (A) Active
Alternate Source (B) Active
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