Generac Power Systems 53187 - Manual (Page 34)

SECTION 1.6- TROUBLESHOOTING
(UNITS WITH 15 INCH STATOR)
1
PART 1
THE REVOLVING FIELD AC GENERATOR
Detailed Instructions (Continued)
1. Set a VOM to Its ’Rxl ’ scale eind zero the m eter.
2. Connect the VOM test probes across W ire No. 5 and
Pin 6 of the Voltage Regulator. The m eter should read
the resistance of the stator excitation w inding (about
0. 53.ohm ).
3. Now , set the VOM to a very high resistance scale
such as ’Rx10,000" or "Rx1 K". Again, zero the m eter.
a. Connect one VOM test lead to bypass W ire No. 5,
the other to a clean fram e ground on the stator. The
m eter should Indicate "infinity".
b. Any reading other than "infinity" indicates a shorted
condition and the stator should be replaced.
4. W ith the VOM still set to a high resistance scale,
connect one VOM test probe to stator W ire No. 5, the
other to stator ac output W ire No. 11 or 22. "Infinity"
should be Indicated.
5. Connect the VOM test probes across W ire No. 5 and
stator AC output W ire No. 33. "Infinity" should be indi­
cated.
Results:
1. If the stator excitation w inding fails any part of the test,
replace the stator assem bly.
2. If the stator excitation w inding checks good, go on to
Test 6.
Figure 4. Excitation W inding Test Points
TEST 6- TEST THERM AL PROTECTOR:
Discussion: You m ay w ish to review the inform ation
on the therm al protector. See Page 1.3-7.
Procedure: Set a VOM to its "Rxl" scale and zero
the m eter. Connect the VOM test probes across stator
w ires No. 2 and 6. See Table 1, Page 6.1-1 for nom inal
resistances.
Results:
1. If norm al excitation w inding resistance w as indi­
cated in Test 5, but "infinity" w as Indicated in Test 6, the
thërm al protector is open and m ust be bypassed.
2. If norm al excitation w inding resistance w as indi­
cated in both Tests 5 and 6, the therm al protector is
good. Go on to Test 7.
TEST 7- TEST EXCITATION LEADS:
Discussion: An open or shorted condition in the
stator excitation w inding's output leads to the Regulator
w ill cause com plete or partial loss of the unregulated
excitation current to the Regulator.
Procedure: Inspect W ires No. 2,6 and 162, betw een
the stator and the Voltage Regulator. Make sure they
are properly connected and undam aged. Use a VOM to
test the w ires tor "continuity".
Results:
1. Reconnect, repair or replace any dam aged, discon­
nected or shorted w ire(s). /
2. If all excitation leads are good, go to Test 11.
TEST 8- CHECK REGULATOR SENSING LEADS:
Discussion: An open or shorted condition in the
sensing leads to the Voltage Regulator w ill result in loss
of sensing (actual voltage) signals to the Voltage Reg­
ulator. The Regulator’s "Sensing" lam p w ill then go out.
Procedure: Carefully inspect W ires SI 5 and SI6,
betw een the Regulator and the sensing transform er.
Also inspect W ires No. 11 and 22, betw een the sensing
transform er and the stator. Use a VOM to test all w ires
for an open or shorted condition.
Results:
1. Reconnect, repair or replace any disconnected,
dam aged or defective w ire(s).
2. If the sensing leads are good, go on to Test 9.
TEST 9- TEST SENSING TRANSFORMER:
Discussion: The Part No. 67680 Voltage Regulator
requires a 240 volts AC sensing signal to operate
properly. You m ay w ish to review the inform ation on the
sensing transfonm er on Page 1.3-6.
PAGE 1.6-6