Generac Power Systems 53187 - Manual (Page 13)

PART 1
THE REVOLVING FIELD AC GENERATOR
Components Inspection and Testing
(Continued)
ROTOR ASSEMBLY;
Clean the Rotor w ith dry, low pressure air (25 psi
or less). If the slip rings are dirty or tarnished, clean
them w ith fine sandpaper. Inspect the Rotor for dam ­
age.
Check the resistance of Rotor w indings w ith a
volt-ohm -m illiam m eter (VOM). Refer to Section 1.6,
"TROUBLESHOOTING (UNITS W ITH 15 INCH STA­
TOR)".
Use an Insulation resistance tester, m egohm m eter,
or Hi-Pot tester to test the resistance of Rotor insula­
tion.
See Section 1.8, •INSULATIO N RESISTANCE
TESTSr.
If the Insulation resistance is low , dry the Rotor w ith
w arm , dry air. DO NOT EXCEED 185* F. (85’ C.). If
resistance is still low after drying, replace the Rotor
Assem bly.
STATOR ASSEM BLY:
1 SECTION 1.3- MAJOR COMPONENTS
(UNITS WITH 15 INCH STATOR)
Clean the Stator Assem bly in the sam e m anner as
the Rotor w as cleaned. Inspect ther Stator for dam age.
Use a VOM to check Stator w indings resistance
(see Section 1.6).
Check the insulation resistance of Stator w indings,
as outlined in Section 1.8.
FLEXIBLE COUPLING:
Carefully inspect the Flexible Coupling (Figure 1,
Item 13) for dam age, cracking. Check m ounting holes
on couplino for elongation and dam age. Replace the
Coupling, if it is dam aged.
FAN RING AND AIR RING BAFFLE:
Inspect the Fan Ring (Figure 1, Item 14) and the
Air Ring Baffle (Item 17) for dam age, cracking. Re­
place, if dam aged.
FLYW HEEL;
Clean the flyw heel. Inspect for dam age, cracks,
w ear, etc. Replace, if necessary.
ENGINE ADAPTER;
Clean the Engine Adapter (Figure 1, Item 23).
Inspect the Adapter carefully for dam age, w ear, crack­
ing, etc. Replace, if necessary.
BRUSH HOLDERS AND BRUSHES:
Inspect Brush Holders and Brushes for dam age,
cracking, chipping, excessive w ear, etc. Replace any
defective or dam aged part. Brushes m ust alw ays be
replaced in com plete sets.
Generator Reassembly
Reassem ble the generator In the reverse order of
disassem bly. The reassem bly process requires a great
deal of care. Com ponents m ust be properly aligned and
retained. Tighten all fasteners to the recom m ended
torque values (see Part 6, "SPECIFICATIONS AND
CHARTS"). Follow ing reassem bly, perform an opera­
tional test of the unit (Section 1.9).
Components In Generator Control Panel
INTRODUCTION:
Rgure 3 (next page) Is an exploded view of the
generator control panel. The Panel houses or m ounts
several Im portant AC generator com ponents, as w ell
as com ponents that are part of the engine DC electrical
system s.
ENGINE ELECTRICAL SYSTEM COMPONENTS;
The Control Panel houses the follow ing com po­
nents that are part of the engine electrical system . For
Inform ation on these com ponents, refer to Part 5 of this
Manual, "ENGINE ELECTRICAL SYSTEM".
□ The 14 and 30 am p Fuses (Item s 4 and 5).
□ The 10 am p DC Circuit Breaker (Item 6).
□ The tw o 12 volts DC Relays (Item s 7 and 8).
□ The DC Voltage Regulator (Item 13).
□ Engine Control Circuit Board (Item 39).
□ Hourm eter (Item 23).
□ Start-Stop Sw itch (Item 24).
□ Preheat Sw itch (Item 25).
AC GENERATOR COMPONENTS:
The follow ing com ponents, housed in the control
panel, are m ajor generator com ponents and w ill be
discussed in this Section and Sub-Section.
□ Excitation Circuit Breaker (Item 11).
□ AC Voltage Regulator (Item 14).
□ The Sensing Transform er (Item 15).
□ AC Circuit Breaker (Item 16).
In addition to the above com ponents, a THERMAL
PROTECTOR is physically im bedded in the w ire w ind­
ings of the Stator Assem bly. A discussion of this com ­
ponent w ill also be included in this Section.
EXCITATION CIRCUIT BREAKER;
The excitation circuit breaker is housed in the con­
trol panel and connected in series w ith .the Stator
Excitation w inding output to the Voltage Regulator.
If this Breaker should open, loss of unregulated
excitation current to the Regulator w ill occur. The Reg­
ulator w ill then shut dow n and loss of regulated excita­
tion current to the Rotor w ill occur. Generator AC output
w ill then be proportional to Rotor residual m agnetism
only (about 2-7% of rated voltage).
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