Generac Power Systems 53187 - Manual (Page 32)

SECTION 1.6- TROUBLESHOOTING
(UNITS WITH 15 INCH STATOR) 1 PARTI
THE REVOLVING FIELD AC GENERATOR
INTRODUCTION:
The follow ing diagnostic test instructions are num ­
bered to correspond w ith the num bered tests in the
troubleshooting 'Row Charts’ on Pages 1.6-1 through
1.6-3. Read the instructions carefully.
TEST 1- CHECK AC OUTPUT VOLTAGE:
Discussion; In order to identify the specific probiem ,
it is necessary to m easure the generator’s AC output
voltage. Som e Installations m ay Include an optional AC
m eter package. Even w hen this is the case, it is a good
idea to verify the AC voltage w ith an external m eter. In
som e cases, the AC m eter(s) on the optional package
m ay be reading incorrectly.
Rem em ber, som e installed units m ay be connected
for dual voltage AC output (120 and/or 240 volts). Som e
units m ay be connected for 120 volts AC output only.
Also see "STAT OR AC CO NNECT ION SYSTEM " on
Page 1.5-2.
Procedure; An AC voltm eter or a volt-ohm -m illiam -
m eter (VOM) m ay be used to m easure voltage. If the
unit is installed in a vehicle, the m eter m ay be connected
to a convenient receptacle. For uninstalled units, con­
nect the VOM across W ires No. T1 (red) and T3 (black)
to obtain a line-to-line voltage reading (240 volts). For a
line-to-neutral reading (120 volts), connect the VOM
across line T1 (red) and T2 (w hite); or across line T3
(black) and T2 (w hite). W ith the unit runing at no-load,
read the AC voltage. Voltage should be 121-127 volts
(line-to-neutral): or 242-254 volts (line-to-line).
Detailed Instructions
Results: Analyze the results of the AC output voltage
test as follow s:
nrSMiTi nnrotRPi
1 22 33 44
■ K
CB1 CB2 )
Q y )—1
T1
)
T2
(WHITE)
-120V___________ ^ 4--------- 120V.
• 240V. •
T3
SHOWN CONNECTED FOR DUAL (BLACK)
VOLTAGE AC OUTPUT. FOR 120
VOLTS OUTPUT, SEE FIGURE 5
ON PAGE 1.5-2.
Figure 1. Stator AC Output Leads
NO TE: Line T 1 (red) and T3 (black) are the tw o "hot''
lines. Line T2 (w hite) Is the "Neutral" line.
1. If the reading is zero volts or residual volts, perform
tests as indicated under Problem 1 of the Flow Charts.
NO TE: "Residual" voltage Is that voltage produced
as a result of Rotor residual m agnetism only. It Is
equal to approxim ately 2 to 7percent of the unit’s
rated voltage. For units rated 120/240 volts, residual
voltage w ill be approxim ately 2.4-0.4 volts (llne-to-
neutral); or 4.8-16.8 volts (llne-to-llne).
2. If the voltage is low , but greater than residual, go to
Problem 2 of the Flow Charts.
3. If AC output voltage is high, go to Problem 3 of the
Flow Charts.
4. If AC output voltage Is norm al at no-load, but drops
excessively w hen electrical loads are applied, go to
Problem 4 of the Flow Charts.
Test 2- Check Voltage Regulator Lamps
Discussion: Refer to 'AC VOLTAGE REGULATOR'
on Pages 1.3-5 and 1.3-6.
Procedure: Gain access to the AC Voltage Regulator
in the control panel. W ith the generator running at
no-load, observe the condition of the Regulator lam ps
(LED’s).
The Voltage Regulator lam ps are norm ally ON
during engine-generator operation. It is suggested that
■ AC VOLTAGE REGULATOR' on Pages 1.3-5 and
1.3-6 be read carefully. The REGULATOR lam p w ill go
out if (a) a Regulator fault exists, or (b) if the Regulator
has shut dow n due to occurence of one or m ore Reg­
ulator shutdow n conditions. The EXCITATION lam p
w ill go out on loss of stator excitation w inding output to
the Regulator. The SENSING lam p w ill go out on loss
of sensing input to the Regulator.
Resülts:
1. if ail lam ps are out, go to Test 11.
2. If the 'Sensing' lam p is out, go to Test 8.
3. If the ’Excitation* lam p is out, go to Test 4.
4. If the 'Regulator* lam p Is out, go to Test 3.
PAGE 1.6-4