IM05805022K
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Instruction Booklet
Effective: January 2012
Page
13
ATC-300+ Automatic
Transfer Switch Controller
Section 4: Typical Function of the ATC-
300+ Controller
The ATC-300+ Controller operates as follows.
The input connections of the ATC-300+ controller are wetted and
work on an opening or closure of an external contact. The output
connections are dry contacts and function depending on input
connections and / or source availability.
120 Vac, 60 Hz is required to power the ATC-300+ controller.
Power is supplied to either pins 1 and 2 or 3 and 4 on the J-7
connector.
Source 1 (S1) sensing is supplied on the J-1 connector; Source 2
(S2) sensing is supplied on the J-2 connector.
K1 and K2 relays, located on pins 1 and 2 (K1) or pins 3 and 4
(K2) on the J-5 connector, along with the K3 and K4 relays,
located on pins 1 and 2 (K3) and pins 3 and 4 (K4) on the J8 con-
nector, are use to control device position. S1 and S2 inputs are
located on pins 1 and 2 (S1) or pins 3 and 4 (S2) on the J-4 con-
nector and are used to sense device position.
K1 and K3 close until the S1 input is satisfied but no longer than
6 seconds before the S1 device Alarm is triggered and the K1 and
K3 relays are deenergized. The K2 and K4 relays function the
same as the K1 relay in that they close until the S2 input is satis-
fied (closed) but no longer than 6 seconds before the S2 device
Alarm is triggered and the K2 and K4 relays are deenergized.
Either input MUST be satisfied prior to resetting the Alarm.
The S1 and S2 connected inputs are wetted inputs that require
a contact closure in order to be satisfied.
The S1 device Alarm will occur if the switch is commanded to go
from S1 to S2 and the S1 connected input is NOT removed within
6 seconds after the command to transfer. The S1 device Alarm
will also occur if the switch is commanded to go from S2 to S1
and the S1 connected input is NOT connected within 6 seconds
after the command to transfer from the neutral position. That is
the K2 relay closes AFTER TDNE or after TD PRE-TRAN times
out, if the S1 connected input is NOT opened within 6 seconds
the K2 relay will open and an S1 device error message, “SOURCE
1 DEVICE”, will be displayed.
A typical transfer request will begin with an S1 outage (S1
becomes unavailable per the programmed setpoints), Engine Test,
or Plant Exercise function. After TDES, if programmed, counts
down, the Generator Start contact will close. For a Plant Exercise
or Engine Test, the S2 available light MUST become available
within 90 seconds or the generator start contacts will reopen.
Once S2 meets the requirements to be considered available, then
TDNE, if programmed, will time down. The pretransfer relay will
energize if S1 is available. TD PRE-TRAN will time down if pro-
grammed and if S1 is available (Engine Test or Plant Exercise).
The K2 relay will energize. The S1 connected input MUST open
within 6 seconds (see above). K2 will open IF TDN is pro-
grammed. TDN will then time down and K2 and K4 will energize
until the S2 connected input is closed (this MUST happen within
6 seconds of K2/K4 closure or the S2 device alarm will trigger
and the K2 and K4 relays will deenergize). Once the S2 con-
nected input is satisfied, K2 and K4 will open and the pretransfer
relay will de-energize.
When S1 returns and becomes available per the programmed set-
points, TDEN, if programmed, will time out. The pretransfer relay
will energize. TD PRE-TRAN, if programmed, will time out. K1
will energize for no longer than 6 seconds or until the S2 con-
nected input is removed. If the 6 seconds times out, then an S2
device Alarm will trigger and K1 will open. Once the input is
removed, then K1 will open if TDN is programmed. TDN will time
down and K1 and K3 will reclose until the S1 input is satisfied,
but for no longer than 6 seconds. If the 6 seconds is reached,
then an S1 device Alarm will be triggered and the K1 and K3
relays will open. If the S1 connected input is satisfied, then K1
will open, the pretransfer relay will de-enerigize, and TDEC will
time down and open the engine start contact.
The Go To Source 2 input (normally closed, open to initiate)
causes the Engine Start contacts to close. Once the S2 sensing
satisfies the setpoints programmed, then a transfer is initiated.
The transfer functions as described above. The controller will
maintain the Engine Start contacts and the S2 connected as long
as the Go To Source 2 input is maintained. Once it is removed, a
retransfer to S1, if S1 is available per the setpoints, will occur and
functions as described above. “Go To Source 2” is displayed on
the controller.
The Monitor Mode input (normally open, close to initiate) is uti-
lized to put the controller in a “Monitor” only state. No other
inputs will affect the operation of the controller when the Monitor
Mode input is initiated. The controller will ONLY monitor the volt-
age and frequency of the S1 and S2 inputs. Changing of the set-
points of the controller MAY be accomplished while in Monitor
Mode. All setpoints are accessible and all timers can be reset.
“ATS Not In Automatic” is displayed on the controller.
The Lockout input (normally closed, open to initiate) is utilized to
place the controller in a state where it will NOT supply any out-
puts regardless the inputs. It is used to monitor the state of any
fault indicating devices. If the fault device trips due to an over
current or over load condition, then a contact opening will place
the controller in the Lockout state. The Alarm contact will change
state when the lockout signal is sensed. “Lockout” is displayed
on the controller. The fault indicating device MUST be reset
before the controller can be reset or the Alarm will continue to
indicate.
