Instructional Booklet
Page
34
Effective: March 2021
Operation and Maintenance Manual,
Automatic Transfer Switch Controller, ATC-900
For more information visit: www.eaton.com
IB140012EN
Appendix A: Feature Timer List and Status Display Messages
Feature: Time Delay Normal to Emergency (TD Normal to Emer-
gency)
TDNE delays the transfer to the Non-preferred Source to permit
stabilization of the Non-preferred power source before the transfer
is made. This timer will begin the countdown from its setting
value when the Non-preferred Source becomes available. If the
Preferred Source should become available during the countdown
of this timer, the timer will be aborted. Also see feature Commit to
Transfer During TDNE Timing.
Feature: Time Delay Engine Start (TD Engine Start)
TDES is used where the source is an engine generator. It delays
initiation of the engine start circuit in order to override momentary
power outages and/or fluctuations. This timer and the associated
engine start circuit will operate with or without control power.
There are two separate start circuits, one for each source when
applications of two generators are selectedwith Time Delay Engine
Start (TDES) timer values individually programmable for each.
When one generator is selected, this timer’s engine start circuit
will operate on generator 2 for source 2. If the source that is being
transferred to has a generator and that source is already available,
the TDES timer will be bypassed.
Feature: Time Delay Emergency to Normal (TD Emergency to Nor-
mal)
TDEN delays the transfer to the Preferred Source to permit stabili-
zation of the Preferred power source before the transfer is made.
This timer will begin the countdown from its setting value when
the Preferred Source becomes available. During the countdown of
this timer, if the Preferred Source should become unavailable, the
timer will be aborted. If the Preferred Source is available and the
Non-preferred Source fails while the TDEN timer is counting down,
the TDEN timer will be bypassed.
Feature: Time Delay Engine Cooldown (TDEC)
TDEC permits the generator to run under a no-load condition after
a transfer from the generator source has been made. Countdown
timing begins when the transfer is completed. In applications
where two generators are selected, the same cool-down is used
for both.
Feature: Time Delay Normal Disconnect (TDND) &
Time Delay Normal Reconnect (TDNR)
Timer to disconnect from an unavailable source after a user
defined period of time (TDND) with a range of 0-10 seconds. It is
then held off from reconnecting to the same source for a user
defined period of time (TDNR) with a range of 0-60 seconds. A
flowchart example is shown in Appendix C.
Feature: Time Delay Emergency Disconnect (TDED) &
Time Delay Emergency Reconnect (TDER)
Timer to disconnect from an unavailable source after a user
defined period of time (TDED) with a range of 0-10 seconds. It is
then held off from reconnecting to the same source for a user
defined period of time (TDER) with a range of 0-60 seconds. A
flowchart example is shown in Appendix C.
Feature: System Nominal Frequency (NOMF)
There are only two choices for system nominal frequency of the
distribution system, 50 or 60 Hertz. The dropout/pickup, underfre-
quency and overfrequency upper and lower setting limits are
based on the nominal frequency value.
Feature: System Nominal Voltage (NOMV)
This refers to the standard system nominal RMS line to line volt-
age. A wide range (110 to 600) of sensing voltage is available to
be programmed. The undervoltage and overvoltage dropout/pickup
setpoint limits are based on the nominal voltage setting.
Feature: Commit to Transfer During TDNE Timing (CTDNE)
This feature provides for selection as to whether or not commit-
ment to transfer is desired when Time Delay Normal to Emergency
countdown has begun. If no commitment is chosen and the Pre-
ferred Source returns to availability when the TDNE timer is count-
ing down, the transfer is aborted and the engine generator (if
applicable) is cooled down.
Feature: Engine Test Mode (TMODE)
This feature provides selection of the type of test that can be initi-
ated by the front panel Engine Test pushbutton. An engine test
without transferring the load to it, or an engine test with a full
transfer of the load to the engine, can be chosen. Load testing is
fail-safe. If the generator fails during testing for any reason, the
ATC-900 will signal the transfer switch to return to normal. The
External option requires a programmable input set to Engine Test
Mode Select and connected to a two position switch. When the
switch is open no transfer occurs during the engine test, when
closed a full transfer of the load occurs during engine test. If the
disable test mode is chosen, the front panel pushbutton cannot be
used to initiate a test.
Feature 6B: Test Engine Run
This feature provides selection of the length of time in hours and
minutes that the ATC-900 will enable the generator contacts
during an Engine Test that was initiated from the front panel push-
button or for the plant exerciser feature, if applicable. Separate
run times can be set for each.
Feature 5J:
Undervoltage Monitoring for Source 2
This feature constantly monitors Source 2 for an undervoltage
condition. When the Source 2 voltage drops to a value equal to or
below the undervoltage dropout setting, the source will become
unavailable. The source’s voltage will then have to rise to a value
that is equal to or above the pickup setting to become available
again.
Underfrequency Monitoring for Source 2
This feature constantly monitors Source 2 for an underfrequency
condition. When the Source 2 frequency drops to a value equal to
or below the underfrequency dropout setting, the source will
become unavailable. The source’s frequency will then have to rise
to a value that is equal to or above the pickup setting to become
available again. This can be disabled in the setpoint settings under
menu 2 in the Setpoints Dropouts/Pickups.
CAUTION
CHANGING THE SYSTEM NOMINAL VOLTAGE OR FREQUENCY SET-
POINTS WILL CAUSE PICKUP AND DROPOUT SETPOINTS TO
CHANGE AUTOMATICALLY TO NEW DEFAULT VALUES.
