IB140036EN
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Instruction Booklet
Effective: October 2014
Page
11
O&M Manual for 40-1200A (480/600 Vac) ATC-900 3-Position,
Open/Closed Transition Contactor Based Transfer Switch
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 47G: Closed/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 frequency,
phase, and voltage before the transfer is initiated.
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.
Two Options for Closed Transition
If closed transition is available on the switch, the user will either
receive 47 D or all of the other options 47 C, E, F, G which can
be changed by the setpoints to disable or enable the function.
Screen 3 of 3 in the System Setup menu (See section 3.4.1) is
where the user will set the transition types of the switch. If the
switch can perform closed transition the user will set up the set-
points depending on the scenario required as shown below.
Closed Transition only (47D) or
Closed Transition > In-Phase > TDN
Closed Transition > In-Phase > LVD
Closed Transition > TDN
Closed Transition > LVD
The user can disable closed transition and just use the following:
In-Phase > TDN
In-Phase > LVD
Also with Closed Transition and In-Phase disabled:
TDN or LVD
Standard Feature 3: Time Delay Emergency to Normal (TDEN)
TDEN delays the transfer to the Normal Source to permit stabili-
zation of the Normal power source before the transfer is made.
This timer will begin the countdown from its setting value when
the Normal Source becomes available. During the countdown of
this timer, if the Normal Source should become unavailable, the
timer will be aborted. If the Preferred Source is available and the
Emergency Source fails while the TDEN timer is counting down,
the TDEN timer will be bypassed.
Standard Feature 4: Time Delay for Engine Cool-Off (TDEC)
TDEC permits the generator to run under a no-load condition
after a transfer from the generator source has been made. Count-
down timing begins when the transfer is completed. In applica-
tions where two generators are selected, the same cool-off timer
setting value is used for both.
Display
There are two displays used on the ATC-900. There is the famil-
iar MIMIC display using LEDs (see below) and the color display
using the push buttons for menu operation.
Source 1 Connected - Status LED
This LED is lit green if Source 1 is connected. This is accom-
plished by sensing the Source 1 breaker via the S1 closed auxil-
iary contact.
Source 2 Connected - Status LED
This LED is lit red if Source 2 is connected. This is accomplished
by sensing the Source 2 breaker via the S2 closed auxiliary con-
tact.
Source 1 Available - Status LED
CAUTION
LOAD ENERGIZE LED IS NOT A POSITIVE INDICATION THAT VOLT-
AGE IS NOT PRESENT ON THE LOAD TERMINALS.
This LED is lit amber if Source 1 meets the criteria for pro-
grammed Source 1 setpoints.
Source 2 Available - Status LED
This LED is lit amber if Source 2 meets the criteria for pro-
grammed Source 2 setpoints.
Source 1 Preferred - Status LED
This LED is lit red if Source 1 is the preferred source choice.
Source 2 Preferred - Status LED
This LED is lit red if Source 2 is the preferred source choice.
Load Energized - Status LED
This LED is lit red if the load is connected to a source that is
available.
CAUTION
CHANGING THE SYSTEM NOMINAL VOLTAGE OR FREQUENCY SET-
POINTS WILL CAUSE PICKUP AND DROPOUT SETPOINTS TO
CHANGE AUTOMATICALLY TO NEW DEFAULT VALUES.
Optional Feature 9B: Maintenance Selector Switch (MSS)
Marked “OFF”, “ON”. This feature provides selector switch dis-
connection of control to transfer thus allowing testing of the
transfer switch control logic circuitry without initiating load
transfer. Positioning the MSS in the “OFF” position isolates the
control circuit, permitting manual operation of the transfer
switch or testing of logic circuitry without load transfer.
Optional Feature 29G: Auto/Manual Operation
(Available for 3-Position ATS only)
This feature provides 2-position auto/manual selector switch
marked “Auto/Manual” which permits the selection of automatic
or manual operation. Once the selector switch is transferred to
manual mode, manual transfer between Normal (S1), Neutral and
Emergency (S2) can be achieved by operating 3-position selector
switch marked “Normal-OFF-Emergency”.
Optional Feature 29G: Auto/Manual Operation
(Available for 2-Position ATS only)
This feature provides 2-position auto/manual selector switch
marked “Auto/Manual” which permits the selection of automatic
or manual operation. Once the selector switch is transferred to
manual mode, manual transfer between Normal (S1) and Emer-
gency (S2) can be achieved by operating another 2-position
selector switch marked “Normal-Emergency”.
