Introduction to troubleshooting, Parti the revolving field ac generator – Generac Power Systems 53187 User Manual
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PARTI
THE REVOLVING FIELD AC GENERATOR
1
SECTION 1.5
INTRODUCTION TO TROUBLESHOOTING
Section 1.5
INTRODUCTION TO TROUBLESHOOTING
DANGER:
GENERATORS
PRODUCE
EXTREM ELY
HIGH
AND
DANGEROUS
VOLTAGES.
CONTACT
W ITH LIVE W IRES OR TERMINALS W ILL RESULT
IN HAZARDOUS AND POSSIBLY FATAL ELECTRI-
SHOCK.
ONLY
PERSONNEL
W HO
HAVE
BEEN TRAINED IN THE SERVICING AND REPAIR
OF
RV
GENERATORS
SHOULD
ATTEMPT
TO
TROUBLESHOOT, TEST OR REPAIR THESE GEN
ERATORS.
Tools and Test Equipment
An RV generator service technician shouid have a
w eii stocked tool box that is fiiied w ith a good seiection
of com m on hand tools. The tool box should contain
com bination w renches and socket w renches in both
standard and m etric sizes. Also, a good nut driver set is
recom m ended.
The follow ing test equipm ent is recom m ended:
□
An accurate volt-ohm -m illiam m eter (VOM),
preferably a precise digital type.
□
A good AC frequency m eter.
D
An insulation resistance tester (m egohm m eter or
Hi-Pot tester).
O A load bank or som e m eans of applying a know n
electrical load to the generator.
Volt-Ohm>Milllammeter (VOM)
If desired, three separate m eters m ay be used, i.e., a
voltm eter, ohm m eter and am m eter. Recom m ended is
an accurate digital type VOM having a ’Diode Check'
m ode.
The service technician m ust be fam iliar w ith his VOM
and m ust know how to use it. He m ust also be fam iliar
w ith generator electrical circuits and m ust be able to
read electrical vriring diagram s and schem atics.
Frequency Meter
The generator’s AC output frequency m ust be know n
if engine governed speed Is to be property adjusted. See
"ROTOR ROTATIONAL SPEED’ in this section.
Figure 1. Typical Volt-Ohm -M llllam m eter (VO M )
Figure 2. One Kind of AC Frequency M eter
Testing Insulation Resistance
Insulation resistance Is a m easurem ent of the In
tegrity of the Insulating m aterials that separate the
electrical w indings from the generator’s steel core. This
resistance can degrade over tim e due to contam inants
such as dust, dirt, grease and especially m oisture.
Inform ation on Insulation resistance test can be found
in Section 1.8,
"INSULATION RESIST ANCE T ESTS'.
PAGE 1.5-1