Guardian 4389 Diagnostic Repair Manual page 83

SECTION 4.2
OPERATIONAL ANALYSIS
ENGINE STARTUP AND RUNNING
With the fuel solenoid open and ignition
occurring, the engine starts. Engine startup and
running may be briefly described as follows:
An AC voltage/frequency signal is delivered to
the circuit board from the generator engine
run winding, via Wire 66A. When AC
frequency reaches approximately 30 Hz, the
circuit board (a) terminates cranking, and (b)
turns on an "engine warm-up timer".
The "engine warm-up timer" will run for about
15 seconds. When this timer finishes timing,
board action will initiate transfer to the
"Standby" power source. As shown in Figure
4 (above), the timer is still running and
transfer has not yet occurred.
Generator AC output is available to transfer
switch terminal lugs E1/E2 and to the
normally open contacts of a transfer relay.
However, the transfer relay is de-energized
and its contacts are open.
Page 4.2-7
PART 4
Figure 4. Circuit Condition - Engine Startup and Running
DC CONTROL