Generac Power Systems 53187 - Manual (Page 134)

SECTION 5.9
TROUBLESHOOTING TEST PROCEDURES
Test 4- Check for Battery Voltage at
Crank Relay (Continued)
PROCEDURE (CONT’D);
Use a volt-ohm -m illiam m eter (VOM ) or a DC volt­
m eter to check for the presence of battery voltage at
relay term inals “A* and *7" as follow s:
1. Set the m eter to a scale that w ill perm it battery
voltage to be read.
2. Connect the positive (+) m eter test lead to relay
term inal "A"; connect the com m on (-) m eter test lead to
term inal 2 (W ire 0) of the engine control circuit board.
The m eter should read battery voltage.
RESULTS;
1. If battery voltage is indicated, go on to Test 5.
2. If battery voltage is NOT indicated, go to Tests 9 and
10
.
L
CONNECT
WIRE NO. " m ? n
IT
17
1SB
ISO
17A
15
ISA
0
TERMINAL
---------- J. --
Figure 1. Crank Relay (CR1)
Test 5- Test Crank Relay (CR1)
DISCUSSSION:
The crank relay (CR1) is used only on Type 1 DC
control system s.
The first step in testing the relay is to check for the
presence of DC voltage at relay term inals "A" and "7".
This has already been done (Test 4).
PROCEDURE;
To test crank relay (CR1) for proper operation,
proceed as follow s:
1. Set a volt-ohm -m illiam m eter (VOM) to read DC volts
and to a scale high enough to read battery voltage.
2. W ith the relay de-energized, connect the m eter test
leads as follow s. In each case, the m eter should read
zero volts.
a. Connect the positive (+) VOM test lead to relay
term inal 5; the com m on (-) test lead to term inal 2 of
the engine control circuit board. Meter should read
“zero'.
PARTS
ENGINE ELECTRICAL SYSTEM
b. Connect the positive (+) m eter test lead to relay
term inal 6; the com m on (-) test loead to circuit board
term inal 2. Meter should read 'zero'.
c. Connect the positive (+) m eter test lead to relay
term inal 4; the com m on (-) test lead to circuit board
term inal 2. Meter should read 'zero'.
DANGER: W hen crank relay (CR1) Is energized
in Step 3, the engine m ay crank and start. Stand
clear of all m oving parts during the test.__________
3. Now , connect a jum per w ire from relay term inal “B"
to term inal 2 of the engine control circuit board. The
relay should energize. THE ENGINE MAY OR MAY
NOT CRANK, DEPENDING ON THE PROBLEM. Test
for closure of the relay contacts as follow s:
a. Connect the positive (+) VOM test lead to relay
term inal 5; the com m on (-) test lead to term inal 2 of
the engine control board. Battery voltage should be
indicated.
b. Connect the positive (+) VOM test lead to relay
term inal 6; the com m on (-) test lead to circuit board
term inal 2. Battery voltage should be read.
c. Connect the positive i+) VOM test lead to relay
term inal 4; the com m on (-) test lead to circuit board
term inal 2. Battery voltage should be indicated.
RESULTS:
1. If the crank relay (CR1) tests good, go to Test 6.
2. Replace the crank relay if it faiis any part of the test.
Test 6- Check for Battery Voltage at Ter­
minal 7 of Circuit Board
DISCUSSION;
During cranking and w ith crank reiay (CR1) ener­
gized, battery voltage is delivered to term inal 1 of the
engine control circuit board. On relay contacts closure,
circuit board term inal 3 is connected to ground via W ire
17A and the relay contacts. The circuit board should
then react t^ delivering battery voltage to a starter
contactor (SC), via circuit board term inal 7 and W ire 56.
This test w ill determ ine if (a) battery voltage is available
to circuit board term inal 1, and (b) if the circuit board is
delivering battery voltage to the starter contactor.
If battery voltage is available to circuit board term i­
nal 1, but the board does not respond by delivering 12
VDC to term inal 7 and W ire 56, either the start/stop
sw itch or the circuit board m ust be defective.
PROCEDURE:
1. Connect the positive (+) test lead of a volt-ohm -m il­
liam m eter (VOM) to term inal 1 of the engine control
circuit board: the com m on (-) test lead to circuit board
term inal 2 (ground).
2. Hold the start/stop sw itch at 'Start'. Crank relay
(CR1) should energize and the VOM should read bat­
tery voltage.
a. If battery voltage is NOT indicated, go to Test 8.
b. If battery voltage is indicated, go on to Step 3.
PAGE 5.9-2