Generac Power Systems 940-2, 941-2 service manual How It Works, NOTE Also see .5, AUTOMATIC, Board

Section 6.1

ENGINE DC CONTROL SYSTEM

HOW IT WORKS	NOTE: Also see Section 3.5, "AUTOMATIC
	CHOKE" and Section 6.2, "A6060 CIRCUIT
	BOARD".

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,

7.5Amp 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.

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.

3.A6060 circuit board action operates the automatic choke through Wire 90.

Page 6.1-2