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IB140036EN
Instruction Booklet
Page
10
Effective: October 2014
O&M Manual for 40-1200A (480/600 Vac) ATC-900 3-Position,
Open/Closed Transition Contactor Based Transfer Switch
single LED at the top of the faceplate provides an immediate indi-
cation as to the device’s operational mode. An integrated Help
Mode provides immediate user assistance in the form of English
language message displays through the use of a front panel Help
pushbutton.
The ATC-900 is communications ready, including Modbus 485,
Ethernet (External), and USB for thumb drives (memory sticks).
3.5.2 Features and Glossary of Terms
NOTICE
WITH RESPECT TO THEIR USE IN THIS DOCUMENT AND AS THEY
RELATE TO AUTOMATIC TRANSFER SWITCH OPERATION, THE FOL-
LOWING WORDS OR PHRASES ARE DEFINED:
A variety of programmable features are available to meet a wide
array of application requirements. Individual features or feature
combinations provide the information required to tailor switches
to individual needs.
Unlike earlier controllers, the ATC-900 comes with standard fea-
tures that are ready to use, with the exception of Closed Transi-
tion, In-Phase, Current metering, and Ethernet. Another
advancement is that there are four (4) standard inputs and four
(4) standard outputs that the operator can easily program by
choosing from a wide array of predefined functions. Additional
inputs and outputs can be added in groups of four (4) up to six-
teen (16) for a maximum of twenty (20) in total. The inputs are
DC wetted (50 Volts at 10 ma) connections for various func-
tional inputs.
Options
The only item that is optional for the transfer switch is the closed
transition optional feature. The switch type also dictates what
can be programmed. For example, a two position contactor
switch cannot have feature TDN (Time Delay Neutral), as it has
no neutral position available. A motor MCS/MCCB type transfer
switch with motor operator cannot have closed transition as the
switching mechanism is not fast enough and will not meet the
time line.
Standard Feature: In-Phase Type Operation
As shown in the feature list of Appendix A for In-Phase, there are
three scenarios for In-Phase:
32C= In-Phase default to Load Voltage Decay
32D= In-Phase default to Time Delay Neutral
32F= In-Phase
There is a setpoint that allows changes to the In-Phase operation:
In-Phase = 0 Disables In-Phase (open transition)
In-Phase = 1 Enables In-Phase Defaults to Alarm
(no Transfer)
In-Phase = 2 Enables In-Phase Defaults to Open
(Time Delay Neutral for 3 position switches)
With the setpoint at "2", a two position contactor, the switch
will transfer, if no synchronisation occurs, to the other source.
The three position will allow the use of TDN.
Closed Transition Types Operation
Optional Feature 47C: Closed/In-phase Transition/Load Voltage
Decay
Closed Transition is a feature that will temporarily parallel two
live sources in a make-before-break scheme when performing a
transfer. This achieves a transfer between sources with no
power interruption. Both sources must be synchronized in fre-
quency, phase, and voltage before the transfer is initiated.
In-phase transition is a feature that will allow a transfer between
two live sources only when the phase difference between the
two sources is near zero. This is an open transition transfer that
prevents in-rush currents from exceeding normal starting currents
in the case where motor loads are being transferred.
Time Delay Load Voltage Decay utilizes the load voltage mea-
surements to sense back EMF that is generated when the trans-
fer switch is in the neutral position. It provides a delay in transfer
in either direction if an unacceptable level is sensed as estab-
lished by a customer programmed level. The transfer will not take
place until the back EMF decays below the acceptable pro-
grammed level. This feature has a separate setting of enabling or
disabling the operation. If disabled, the transfer switch will not
delay in the neutral position and will transfer between the
sources as fast as possible.
Optional Feature 47D: Closed Transition Only
Closed Transition is a feature that will temporarily parallel two
live sources in a make-before-break scheme when performing a
transfer.
This achieves a transfer between sources with no power inter-
ruption. Both sources must be synchronized in frequency, phase,
and voltage before the transfer is initiated.
If the logic is forced into a fail safe mode (i.e. loss of connected
source), the logic will perform a load voltage decay open trans-
fer.
Optional Feature 47E: Closed/In-Phase Transition/Time Delay
Neutral
Closed Transition is a feature that will temporarily parallel two
live sources in a make-before-break scheme when performing a
transfer. This achieves a transfer between sources with no
power interruption. Both sources must be synchronized in fre-
quency phase, and voltage before the transfer is initiated.
In-phase transition is a feature that will allow a transfer between
two live sources only when the phase difference between the
two sources is near zero. This is an open transition transfer that
prevents in-rush currents from exceeding normal starting currents
in the case where motor loads are being transferred.
Time delay neutral provides a time delay in the transfer switch
neutral position when both breakers are open. This delay takes
place when the load is transferred in either direction to prevent
excessive in-rush currents due to out of phase switching of large
motor loads.
Optional Feature 47F: Closed/Load Voltage Decay
Closed Transition is a feature that will temporarily parallel two
live sources in a make-before-break scheme when performing a
transfer. This achieves a transfer between sources with no
power interruption. Both sources must be synchronized in fre-
quency, phase, and voltage before the transfer is initiated.
Time Delay Load Voltage Decay utilizes the load voltage mea-
surements to sense back EMF that is generated when the trans-
fer switch is in the neutral position. It provides a delay in transfer
in either direction if an unacceptable level is sensed as estab-
