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3.7.1 SYSTEM READY LED
The "System Ready LED" is lit if the Gxxx or Hxxx panel is in Auto,
there are no transfer errors (excluding comm's error or fail to
synch), and the Maintenance Disconnect Switch is in AUTO. If the
comm's are bad then the system ready light will flash but the sys-
tem will still function with local control. Under all circumstances, if
the Generator is not in the AUTO position, the switch controller will
locally close the switch to Utility power if it is available.
3.7.2 STANDBY OPERATING LED
This LED will light when the Generator is running. This is deter-
mined by the Generator frequency being between 20 and 80 Hz.
This LED will flash along with the Utility Available LED to indicate
a "fail to sync" condition.
3.7.3 SWITCH POSITION LED'S
The transfer switch position is monitored by two auxiliary contacts
mounted on the transfer switch mechanism. These LED's display
the position of the main contacts.
If there is a transfer switch error (fail to close or open) the appro-
priate Led will flash. In the case of an OTTS switch, both LED's
will flash.
3.7.4 UTILITY AVAILABLE LED
This LED indicates that Utility voltage is present but does not
indicate that it is within the tolerances set by the H panel (as this
is determined in the H panel). It does indicate that Utility voltage is
within 70-130% of nominal.
This led will flash along with the standby operating led to indicate
a "fail to sync" condition.
3.7.5 TEST SWITCH AND CURTAILMENT INPUT
The Test switch will only operate if the communications link is
active, also the generator must be stopped, i.e., not in minimum
run or cooldown.
Pressing the switch will cause the generator controller to com-
mand a transfer to standby using all the pre-programmed timers
and settings. The unit will transfer back to utility after the switch is
pressed again and the "return to utility" timer expires. Pressing the
"return to normal" switch will force this timer to expire and the unit
to return to the utility position. The switch can also be "mimicked"
via a digital input on (J1-17) for curtailment. The pin needs to be
cycled to start the test and also cycled to stop the test.
3.7.6 FAST TEST BUTTON
The Fast Test button will only operate if the communications link
is active. Pressing the button will cause the Generator controller to
command a transfer to STANDBY using all the standard settings
but with reduced time delays. Specifically the following timers are
reduced to 1 second:
Line Interrupt Delay timer•
Engine Warmup timer•
Engine Minimum Run timer•
Engine Cooldown timer•
Return to Utility timer•
NOT affected are:
Signal Before Transfer timer•
Time Delay Neutral timer•
The unit will initiate a transfer back to Utility after 5 seconds of the
transfer mechanism in the Standby position.
3.7.7 RETURN TO NORMAL SWITCH
This switch will abort the Return to Utility timer and cause the
system to return to Utility operation (assuming the Utility source is
good). It will not operate if the Communications link is bad.
3.7.8 MAINTENANCE DISCONNECT SWITCH (AUTO/
MANUAL)
In the Manual position, the transfer switch is physically isolated
from the signals that tell it to operate, the transfer mechanism will
not change state in the Manual position. This position should be
used when manually operating the transfer switch mechanism. In
the Auto position, the transfer switch is operated by the switch
controller. For automatic operation the switch should be left in the
Auto position.
3.8 SEQUENCE OF OPERATION
When acceptable Utility source voltage is available, the Maintenance
Disconnect switch is in AUTO and the communication link to the
generator is good, observe the following:
Utility Available LED, on front of door, is ON.•
Utility Switch Position LED, on front of door, is ON.•
System Ready LED, on front of door, is ON.•
3.8.1 SEQUENCE 1 - UTILITY VOLTAGE DROPOUT
Utility Voltage goes outside of the value set in the generator •
control panel (range is 5-25 Vrms of nominal voltage, factory
default setting is +/- 25 Vrms). If the communication link is not
good the ATS controller will take control and the range is 70 to
130% of the nominal voltage selected with a 5 second utility
loss timer and a 30 second utility return timer.
Voltage dropout triggers sequence 2.•
Section 3 — Operation
HTS “Wn” Type Transfer Switch
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