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Sequence of Operations –
Automatic Mode
Standard Transition
Source 1 Power Failure:
When Source 1 voltage or frequency has fallen below the
preset "Fail" values, the controller initiates the Time Delay.
Source 2 Start Timer (Engine Start Timer "P") cycle. 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 Source 2 Timer
(W) begins its timing cycle to ensure voltage and frequency
stabilization before transfer. 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
operate the main transfer operator. The load is now transferred
to Source 2 line. The transfer switch is mechanically locked.
SN limit switch waits for the next operation to Source 1.
Restoration of Source 1 Power:
When Source 1 power reach the preset "Restore" values,
the controller initiates re-transfer to Source 1 sequence. The
delay to Source 1 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 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.
Delayed Transition
Source 1 Power Failure:
When Source 1 voltage or frequency has fallen below the
preset "Fail" values, the controller initiates the Time Delay
Source 2 Start (Engine Start Timer "P" cycle. 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 re-transfer. 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
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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.
Restoration of Source 1 Power:
When Source 1 power reach the preset "Restore" values, the
controller 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.
Relay Module
Figure S4-9 : Electrical Panel
13
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