DC control

Part 4

Section 4.2

Operational analysis

Printed circuit board action delivers 12 volts DC to the fuel solenoids (FS1 & FS2), via Wire 14. The fuel solenoids energize open and fuel is available to the engine. Wire 14 supplies power to the choke solenoid (CS). Circuit board action grounds Wire 90, energizing the choke solenoid cyclically during cranking and continuously while running.

As the engine cranks, magnets on the engine flywheel induce a high voltage into the engine ignition magnetos

(IM1/IM2). A spark is produced that jumps the spark plug (SP1/SP2) gap.

During cranking, Wire 4 supplies 3-5 VDC (9-10 VDC isolated) to the rotor for field flash.

With ignition and fuel flow available the engine can start.

Figure 3. Circuit Condition - Engine Cranking

CB

CONTROLLER DISPLAY

Cranking Attempt #1

44

11

33

22

00

240VAC GENERATOR OUTPUT

NEUTRAL

 

N1

240 VAC

 

 

 

 

UTILITY

 

 

INPUT

OPTIONAL

 

 

BATTERY WARMER

N1

N2

 

 

 

CONTROLLER

 

 

 

PRINTED CIRCUIT BOARD N1 N2

 

85

1

 

 

 

86

2

J1

 

TO

13

3

 

7.5 AMP FUSE

 

PCB

18

4

 

 

 

 

 

GOVERNOR

 

J3

SELF RESETTING FUSE

ACTUATOR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

J2

 

 

 

 

 

 

1

2

3

4

5

6

7

8

9

10

11

12

13 14

15

16

17 18

 

 

 

 

 

 

4

 

 

 

 

 

 

 

 

 

 

0

14

 

23

 

 

15B

 

0

56

 

 

 

 

 

 

14

820

 

817

 

14

 

818

 

 

CS

FS

819

900

0

0

LEGEND

 

BA - BRUSH ASSEMBLY

LOP - LOW OIL PRESSURE SWITCH

CB - CIRCUIT BREAKER, MAIN OUTPUT

SC - STARTER CONTACTOR

CS - CHOKE SOLENOID

SCR - STARTER CONTROL RELAY

FS - FUEL SOLENOID

SM - STARTER MOTOR

HTO - HIGH TEMPERATURE SWITCH

SP_ - SPARK PLUG

IM_ - IGNITION MODULE

 

 

 

LED BOARD

820

1

L1

817

2

L2

818

3

 

819

4

 

0 GROUND

15B

+ BATTERY

23 TRANSFER

=12 VDC ALWAYS PRESENT

=AC VOLTAGE

=GROUND FOR CONTROL PURPOSES

=12 VDC DURING CRANKING ONLY

=12 VDC DURING ENGINE RUN CONDITION

=DC FIELD EXCITATION

=5 VDC TO LED

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Image 111
Generac Power Systems 13 kW NG, 10 kW LP, 7 kW NG, 9 kW NG, 8 kW LP, 17 kW LP, 20 kW LP manual Circuit Condition Engine Cranking