Generac Power Systems 53187 - Manual (Page 133)

PARTS
ENGINE ELECTRICAL SYSTEM
1
SECTION 5.9
TROUBLESHOOTING TEST PROCEDURES
Section 5.9
TROUBLESHOOTING TEST PROCEDURES
General
The test procedures that follow correspond to the
num bered tests of Section 5.8, TROUBLESHOOTING
FLOW CHARTS.
W hen perform ing diagnostic tests on the engine-
generator, it is recom m ended that the W IRING DIA­
GRAM and ELECTRICAL SCHEMATIC for the partic­
ular m odel being tested be used. Som e differences
m ay exist betw een m odels and using the appropriate
diagram and schem atic w ill help prevent m istakes.
TTie w riter has arbitrarily divided the different en­
gine DC control system s into three types. Read Section
5.1 carefully to identify these types (Type 1,2 and 3).
Test 1- Check 14 Amp Fuse (F1)
DISCUSSION;
The 14 am p fuse is physically m ounted on the
generator control panel. The fuse is electrically con­
nected in series w ith the DC pow er supply to the engine
control circuit board. A blow n fuse w ill open the DC
pow er supply to the circuit board, preventing engine
cranking and startup.
PROCEDURE;
Push in on fuse holder cap and turn counterclock­
w ise to rem ove. The fuse and cap w ill com e off to­
gether. Use a volt-ohm -m illiam m eter to test the fuse for
“continuity".
RESULTS;
1. A reading of "infinity" indicates the fuse elem ent has
m elted open. Replace the fuse w ith an identical 14 am p
fuse.
2. If the m eter reads "continuity", go on to Test 2.
Test 2- Check Battery Cables
DISCUSSION;
Oxidation can form on battery cable term inals and
clam ps, as w ell as battery posts. The resultant film can
result in an effective open-circuit, w ith the sam e results
as a dead battery. Battery cable term inals and clam ps,
as w ell as battery posts, m ust be clean and free of
corrosion.
PROCEDURE;
Inspect battery cable clam ps and term inals, the
cables them selves, and battery posts for evidence of
corrosion. Clean as required. Reconnect the cables
and m ake sure thay are tight.
RESULTS;
1. Clean, tighten or replace battery cables (Including
starter cable) as necessary.
2. If battery cables are not the cause of the problem , go
on to Test 3.
Test 3- Check the Battery
DISCUSSION;
Storage batteries that are unused for any length of
tim e can self-discharge. If the engine cranks too slow ly,
a discharged battery m ay be the cause of the problem .
In som e cases the battery m ay be too w eak to crank
the engine at all.
PROCEDURE;
See Section 5.2, ENGINE CRANKING SYSTEM.
Tw o different m ethods of testing the battery are given
in that section. These tw o m ethods are:
□ A battery capacity test.
□ Specific gravity tests using a battery hydrom eter. \
RESULTS:
1. Recharge or replace the battery as necessary.
2. If battery is in good condition and properly charged,
go on to Test 4.
Test 4- Check for Battery Voltage at
Crank Relay (CR1)
DISCUSSION:
Crank relay (CR1) Is used only on Type 1 control
system s. These system s utilized early production en­
gine control circuit boards and included both a crank
relay (CR1) and a run relay (CR2). The crank relay,
w hen energized by setting the start/stop sw itch to
"Start" position, acts to initiate engine cranking and
startup as follow s:
□ Connects term inal 3 (W ire 17A) of the engine control
circuit board to ground. Circuit board action then
delivers battery voltage to the starter contactor (SC)
to initiate cranking.
□ Delivers battery voltage to term inal 1 of the circuit
board, to turn the board ON. Circuit board action then
delivers battery voltage to a fuel solenoid and a fuel
pum p, so the engine can start and run.
□ Closure of the crank relay contacts delivers battery
voltage to a preheat contactor, for engine preheat.
If battery voltage is not available to the crank relay
(CR1) for any reason, cranking cannot occur.
PROCEDURE:
The crank relay (CR1) Is housed Inside the gener­
ator control panel. See Rgure 1, next page.
NO TE: Crank relay (CR1) and run relay (CR2) are
m ounted
In the panel sIde-by-sIde. Crank relay
(CR1) has a total of eleven (11) term inals; run relay
(CR2) has eight (8) term inals.
PAGE 5.9-1