Generac Power Systems 53187 - Manual (Page 25)

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-
<CAL 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