Eaton Static Transfer Switch 2000A 3-Pole Installation and Operation Manual 164001127—Rev 01 41
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The STS has three modes of operation:
• Normal
• Redundant
• Bypass
88..11 NNoorrmmaall MMooddee OOppeerraattiioonn
For normal operation, the MODE OF OPERATION toggle switch on the ROI panel should be set to NORMAL.
The STS should be left in Normal mode for all but unusual circumstances. (See Figure 16, Redundant Operator
Interface (ROI).)
In Normal mode, when the active source falls out of specification, transfer to the other power source is
automatic. There are three (3) operational choices that govern automatic transfers:
1. Transfer algorithm: choose between VSS or POG; default=VSS. (See 10.2 Switch Settings Screen and
1.3 Transfer Process: Algorithms .)
2. Preferred Source: choose whether Source 1 or Source 2 is the preferred power source; default=Source 1
(see Figure 13 Home screen).
3. re-transfer = Yes or No: after a transfer to the alternate source (i.e., the non-preferred source), should the
STS automatically re-transfer back to preferred source when that source is good or remain on the alternate
source? Default=Yes (See 10.2 Switch Settings Screen).
88..11..11 PPrreeffeerrrreedd SSoouurrccee
In Normal mode operation, the load is connected to the designated Preferred Source by default, as long as the
voltage and frequency of all phases of that source are within acceptable limits.
• At initial startup, Source 1 is the default Preferred Source.
• The Preferred Source can then be set by a logged-in user with at least operator access privileges on the
Home screen.
• Either input power source can be designated as the Preferred Source by the setting the Preferred Source –
1 / 2 virtual control on the Home screen.
• When the Preferred Source fails—that is, when the Preferred Source goes outside acceptable predefined
limits—the STS transfers the load to the alternate source using the chosen algorithm, VSS or POG.
88..11..22 RReettrraannssffeerr CCoonnttrrooll
The Retransfer control determines whether the STS maintains an affinity for the Preferred Source whenever it
is within acceptable parameters.
Retransfer = Yes:
• If Re-transfer = Yes, the load has an affinity for the Preferred Source. After transferring the load to the
alternate source, when the Preferred Source returns to a condition that is within tolerance for at least the
preset adjustable retransfer time delay, the load will be automatically be re-transferred back to the
Preferred Source.
• The load will always be transferred to the Preferred Source whenever the source is in-tolerance however
long the Preferred Source takes to come back within specification—and will remain connected to the
Preferred Source until it fails or a transfer is manually initiated.
• Retransfer = Yes is the default setting for this control.
Retransfer = No:
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