Generac Power Systems 53187 - Manual (Page 110)

SECTION 5.1
INTRODUCTION TO DC CONTROL SYSTEMS
I
PARTS
ENGINE ELECTRICAL SYSTEM
Operating Diagram- Type 3 DC Control System
Operation of the Type 3 DC control system may be
briefly described as follows:
SHUT DOWN;
Battery voltage is available to the starter relay and
to Terminal #1 of the engine control circuit board, via
Wire 13, 10 amp circuit breaker (CB3), 14 amp fuse
(FI), and Wire 15. However, the starter relay Is de-en-
ergized and its contacts are open. Engine control circuit
board action also holds the circuit open.
CRANKING;
When the start/stop switch is set to its
position, the following occur
•Start"
□ Wire 17, from Terminal #3 of the circuit board, is
connected to ground via the start/stop switch.
□ Circuit board action delivers DC voltage to the starter
relay actuating coil, via circuit board Terminal #7,
Wire 56. The starter relay then energizes and its
contacts close.
□ On closure of the starter relay contacts, DC power is
delivered to the starter solenoid. The solenoid ener­
gizes and the starter cranks the engine.
□ Engine control board action delivers DC voltage to
Terminal #8 and to the generator's field boost circuit,
via Wire 4A.
□ Circuit board action delivers DC power to (a) a fuel
solenoid (FS): (b) a fuel pump (FP); and an hour-
meter (HM). These devices turn on to deliver fuel to
the engine and the engine starts.
RUNNING;
On engine startup, the start/stop switch is released.
Circuit board action then terminates the DC current to
the starter relay coll and cranking ends. Circuit board
action continues to deliver DC voltage to the Wires 14
circuits and the engine continues to run.
SHUTDOWN;
When the start/stop switch is set to its "Stop" posi­
tion, Wire 18 and circuit board Terminal #4 are con­
nected to ground through the switch. Circuit board
action then opens the circuits to Wires 14. The fuel
pump (FP) and the fuel solenoid (FS) de-energize, fuel
flow stops, and the engine shuts down. The hourmeter
(HM) shuts down, as well.
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