Generac Power Systems 941-2 Service Manual page 92

Section 6.1
ENGINE DC CONTROL SYSTEM
HOW IT WORKS
ENGINE NOT RUNNING:
1. Battery output (12VDC) is available to the contacts of a starter
contactor (SC). However, the contacts are open.
2. Battery output is delivered to Terminals J2 - 5 of the A6060 cir-
cuit board, via Wire 13, a 15 amp fuse, and Wire 15. Circuit
board action holds this circuit open.
3. Battery output is available to a Battery Charge Rectifier (BCR)
via Wire 13, 15 amp Fuse (F1), Wire 15, a Resistor (R1) and
Wire 15A.
PRIMING:
When the Primer Switch (SW2) is closed, battery volt-
age is delivered to the engine Fuel Pump via Wire 13,
7.5 Amp Fuse (F1), the Switch contacts (SW2) and
Wire 14A. The Fuel Pump will operate to draw fuel
from the tank and "prime" the fuel lines.
NOTE: On units with LP gas fuel system, the Fuel
Lockoff Solenoid (FS) will be turned on by closing
the Primer Switch.
CRANKING:
When the Start-Run-Stop Switch is held at "START",
the Wire 17 circuit from the A6060 circuit board is
connected to frame ground. Circuit board action then
initiates the following events:
1. Battery voltage is delivered to the Starter Contactor (SC) coil
via Wire 56.
a. The SC coil energizes and its contacts (SC)
close after a few seconds.
b. Closure of SC contacts deliver battery voltage to
the Starter Motor (SM1) via Wire 16. The engine
cranks.
2. Battery voltage is delivered to the Wire 14 circuit.
a. The Fuel Pump (FP) turns on.
b. Power is available to the Ignition Module (IM)
and ignition occurs.
c. Power is available to the Inverter Fan for opera-
tion.
3. A6060 circuit board action operates the automatic choke
through Wire 90.
Page 6.1-2
NOTE: Also see Section 3.5, "AUTOMATIC
CHOKE" and Section 6.2, "A6060 CIRCUIT
BOARD".
RUNNING:
With fuel flow and ignition available, the engine starts
and runs. The operator releases the Start-Run-Stop
switch to its "RUN" position.
1. The Wire 18 circuit is now open to ground. Circuit board action
terminates the 12 VDC to the Starter Contactor (SC). The SC
contacts open and cranking ends.
2. Choking action ends and the carburetor choke plate is posi-
tioned by the Choke Heater (CH).
3. Circuit board action continues to power the Wire 14 circuit- fuel
flow and ignition continue.
NORMAL SHUTDOWN:
When the Start-Run-Stop switch is held at "STOP",
the Wire 18 circuit is connected to frame ground.
A6060 circuit board action then terminates the DC
flow to the Wire 14 circuit.
1. Fuel Pump (FP) shuts down.
2. Ignition terminates.
3. Engine shuts down.
ENGINE PROTECTIVE DEVICE SHUTDOWN:
Refer to "Oil Filter Support" on Page 5.1-3 and
Section 6.5. The engine mounts a Low Oil Pressure
Switch (LOP) and a High Oil Temperature Switch.
Section 6.5 also lists several other shutdown capabili-
ties of the Impact Plus generator system.