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Delayed Transition
Source 1 Power Failure:
When the test is initiated, the controller initiates the Time
Delay Source 2 Start (Engine Start Timer "P") cycle. A manual
CANCEL button is provided to cancel the test if desired. Upon
completion of the (P) time delay, an Engine start Signal is sent
to Source 2. When Source 2 voltage and frequency reach the
preset "Restore" values, the time delay to open Source 1 timer
(W) begins its timing cycle to ensure voltage and frequency
stabilization before retransfer. A manual pushbutton BYPASS is
provided to bypass the "W" time delay if desired. After the (W)
time delay, the MX controller initiates a transfer signal through
the Relay Driver Module to operate the main transfer operator.
The load is now transferred to the Open position. The time delay
to Source 2 timer (DW) begins its timing cycle. After the (DW)
time delay, the MX controller initiates a transfer signal through
the Relay Driver Module to operate the main transfer operator.
The load is now transferred to Source 2 line. The transfer
switch is mechanically locked. SN limit switch awaits the next
operation to Source 1.
Timer Designations as they appear in the SET menu
ATS TYPE
P
Standard Transition
Time Delay
S2 Start
Delayed Transition
Time Delay S2
Start
Source 1 Fails
Transfer to Source 2
Zenith Automatic Transfer Switch |
W
DW
Time Delay
S2 Stable
Time Delay S2
ATS Open Time
Stable
to S2
S4-11 Showing timer set menu
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Restoration of Source 1 Power:
Deactivating the test switch initiates re-transfer to Source 1
sequence. The delay to open Source 2 Timer (T) begins its timing
cycle to ensure voltage and frequency stabilization before
retransfer. A manual pushbutton BYPASS is provided to bypass
the "T" time delay if desired. After the (T) time delay, the MX
controller initiates a transfer signal through the Relay Driver
Module to operate the main transfer operator. The load is now
transferred to the Open position. The time delay to Source 1
timer (DT) begins its timing cycle. After the (DT) time delay, the
MX controller initiates a transfer signal through the Relay Driver
Module to operate the main transfer operator. The load is now
transferred to Source 1 line. The transfer switch is mechanically
locked. SE limit switch awaits the next operation to Source 2.
Immediately after re-transfer, the S2 Stop Delay Timer (Delay
to Engine Stop "U") begins its cycle to allow Source 2 Engine
to run unloaded. A manual pushbutton BYPASS is provided to
bypass the "U" time delay if desired. Upon completion of the
(U) timing cycle, the controller sends an Engine stop signal.
T
Time Delay S1
Stable
Time Delay S1
Stable
Source 1 Returns
DT
U
S2 Stop Delay
ATS Open Time
S2 Stop Delay
to S1
Transfer to Source 1
Engine
Cooldown
15
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