Why does the Delayed Transition Transfer Switch (DTTS) remain in the neutral position instead of transferring?

How can we help you today?

Case 1. Remaining in neutral when transferring from N to E -- no Alarms.

The controller does not give any error message and the indicator lights show that the ATS is connected to the Emergency Source even while the TS mechanism itself is disconnected from both Normal and Emergency Sources.

This means that the controller was not set up for Delayed Transition mode. This usually happens with replacement controllers where the end-user fails to set up the related DIP switches for the Transition Mode.

For the Group G controller, verify:

For the Group 5 controller, verify:

NOTE: If set up incorrectly, turn OFF the unit completely before adjusting the DIP switches. A transfer may happen if the unit is not removed from power.

Case 2. Remaining in neutral when transferring from N to E or cannot OPEN from E -- with Alarms

The controller was set up correctly for Delayed Transition mode but it shows “Transfer Failure” or “ATS position error” alarms. When transferring from N to E, the mechanism can OPEN from N but cannot close to E. When transferring from E to N, the mechanism cannot OPEN from E.

It is possible that the REX module (for Series 300) or the DOC module (for the 7000/4000 Series) are disconnected. This is most commonly encountered in open-style (enclosure-less) units since the connectors are not pre-installed from the factory.

For the Series 300, verify that both the flat ribbon cable connecting the REX module to the controller and the 24-pin harness connector from the field wiring are connected properly:

For the 7000/4000 Series, verify that both the connector going to the controller and the connector from the field wiring are connected to the DOC module:

NOTE: Turn off the unit completely before attempting to connect the plugs. A transfer may happen if the unit is not removed from power.

Case 3. Remaining in neutral when transferring in both directions -- with Alarms

The controller was set up correctly and the wiring and connectors are confirmed OK but transfers from N to E and/or E to N fail and there are corresponding alarms for Transfer Failure or ATS Position Error.

The issue may already involve problems with the elements in the operator circuit. It may be due to problems with any or a combination of the following devices: control contacts, the control relays SE/ER/SE2/ER2, the contactors SER/ERR/SER2/ERR2 for the G-Frame, the coils, rectifiers, and wiring.

For this case, on-site assistance from ASCO Power Services is recommended.