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3.2.2 “OFF” POSITION
This switch position shuts down the engine. This
position also prevents automatic operation.
3.2.3 “MANUAL” POSITION
Set the switch to Manual to crank and start the
engine. Transfer to standby power will not occur
unless there is a utility failure.
With the switch set to AUTO, the engine may
crank and start at any time without warning.
Such automatic starting normally occurs when
utility power source voltage drops below a pre-
set level or during the normal exercise cycle. To
prevent possible injury that might be caused
by such sudden starts, always set the switch to
OFF and remove the fuses before working on or
around the generator or transfer switch. Then,
place a “DO NOT OPERATE” tag on the generator
panel and on the transfer switch.
3.3 AUTOMATIC TRANSFER
OPERATION
To select automatic operation, do the following:
1. Make sure the transfer switch main contacts are
set to their “Utility” position, i.e., loads connected
to the utility power source (Figure 3.2).
2. Be sure that normal utility power source voltage
is available to transfer switch terminal lugs N1
and N2.
3. Set the generator’s AUTO/OFF/MANUAL switch to
AUTO.
4. Set the generator’s main circuit breaker to its ON
(or closed) position.
With the preceding steps complete, the generator will
start automatically when utility source voltage drops
below a preset level. After the unit starts, loads are
transferred to the standby power source. Refer to
Section 3.4, “Sequence of Automatic Operation.”
3.4 SEQUENCE OF AUTOMATIC
OPERATION
The generator’s control panel houses a control logic
circuit board. This board constantly monitors util-
ity power source voltage. Should that voltage drop
below a preset level, circuit board action will signal
the engine to crank and start. After the engine starts,
the circuit board signals the transfer switch to acti-
vate and connect load circuits to the standby power
supply (load terminal lugs T1/T2 connect to terminal
lugs E1/E2).
Upon restoration of utility source voltage above a
preset level, generator circuit board action signals the
transfer switch to transfer loads back to that power
supply. After retransfer, the engine is signalled to shut
down.
The actual sequence of operation is controlled by
sensors and timers on a control logic circuit board,
as follows:
A. Utility Voltage Dropout Sensor
• This sensor monitors utility source voltage.
• If utility source voltage drops below about 70
percent of the nominal supply voltage, the sensor
energizes a 15-second timer.
• Once the timer has expired, the engine will crank
and start.
B. Engine Warm-up Time Delay
• This mechanism lets the engine warm up for
about 10 seconds before the load is transferred
to the standby source.
C. Utility Voltage Pickup Sensor
• This sensor monitors utility power supply volt-
age. When that voltage is restored above 70 per-
cent of the nominal source voltage, a retransfer
time delay starts timing.
D. Retransfer Time Delay
• This timer runs for about 15 seconds.
• At end of a 15-second delay, circuit board
action de-energizes transfer relay in the transfer
switch.
• Retransfer to utility power source then occurs.
E. Engine Cool-down Timer
• When the load is transferred back to utility power
source, the engine cool-down timer starts tim-
ing.
• The timer will run for about one minute, and the
generator will then shut down.
Section 3 — Operation
Air-cooled 11 kW Generators