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2. Auto
•
Will start and run if Utility fails for 10 consecu-
tive seconds.
•
Will start a five (5) second engine warm-up
timer.
•
Will not transfer if utility subsequently returns.
•
Will transfer to generator if utility is still not pres-
ent.
•
Will transfer back to utility once utility returns
(above 75% of nominal) for 15 seconds.
•
Will transfer back to utility if the generator is
shut down for any reason (such as the switch is
in the OFF position or a shutdown alarm.
•
After transfer, will shut down engine after one (1)
minute cool-down time.
3. Exercise
•
Will not exercise if generator is already running
in either Auto or Manual mode.
•
During exercise, the controller will only transfer
if utility fails during exercise for 10 seconds, and
will switch to Auto mode.
3.3.4 UTILITY RESTORED
Initial Condition:
Generator supplying power to
customer load. When the utility returns (above 75%
of nominal), a 15 second return to utility timer will
start. At the completion of this timer, if the utility
supply is still present and acceptable, the control
will transfer the load back to the utility and run the
engine through a one (1) minute cool down period
and then shut down. If utility fails for three (3) sec-
onds during this cool down period, the control will
transfer load back to the generator and continue to
run while monitoring for utility to return.
3.4
MANUAL TRANSFER OPERATION
3.4.1 TRANSFER TO GENERATOR
POWER SOURCE
To start the generator and activate the transfer switch
manually, proceed as follows:
1. Set the generator's AUTO/OFF/MANUAL switch to
OFF .
2. Set the generator's main circuit breaker to its
OFF (or OPEN) position.
3. Turn OFF the utility power supply to the transfer
switch using the means provided (such as a utility
main line circuit breaker).
Section 3 — Operation
Air-cooled Generators
DANGER
Do not attempt to activate the transfer switch
manually until all power voltage supplies to the
switch have been positively turned off. Failure
to turn off all power voltage supplies may result
in extremely hazardous and possibly fatal elec-
trical shock.
4. Use the manual transfer handle inside the trans-
fer switch to move the main contacts to their
STANDBY position, i.e., loads connected to the
standby power source (Figure 3.3).
5. To crank and start the engine, set the AUTO/OFF/
MANUAL switch to MANUAL.
6. Let the engine stabilize and warm up for a few
minutes.
7. Set the generator's main circuit breaker to its ON
(or CLOSED) position. The standby power source
now powers the loads.
Figure 3.3 – Manual Transfer Switch Operation
3.4.2 TRANSFER BACK TO UTILITY POWER
SOURCE
When utility power has been restored, transfer back
to that source and shut down the generator. This can
be accomplished as follows:
1. Set the generator's main circuit breaker to its
OFF (or OPEN) position.
2. Let the engine run for a minute or two at no-load
to stabilize the internal temperatures.
3. Set the generator's AUTO/OFF/MANUAL switch
to its OFF (or OPEN) position. The engine should
shut down.
4. Check that utility power supply to the transfer
switch is turned OFF .
19
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