Westerbeke 5.0KW BCG-60Hz Service Manual page 78

Be GENERATORS TROUBLESHOOTING
TESTING THE EXCITER WINDINGS
AC voltage can be measured across the capacitor electrical
connections while the generator is operating. This voltage
may be as high as 350 to 400 volts AC.
This AC voltage build-up is accomplished as the exciter
winding for each capacitor charges the capacitor and the
capacitor discharges back into the winding. This flow of
saturating AC in the exciter winding produces a phase-
imbalance type of filed that affects the auxiliary windings
of the rotor.
The AC voltage reading is taken between the two electrical
connections on each separate capacitor with the generator
operating at its correct no load speed.
EXCITER WINDING INTEGRITY (RESIDUAL AC VOLTAGE)
The condition of each exciter winding can be determined
by the residual AC voltage each exciter winding should be
producing with the generator running at proper no load speed.
To do this: Unplug all connections from the capacitor. Locate
the electrical connection for each winding end. Place your
AC volt meter connects across these two connections. Start
the generator and observe the residual AC voltage produced
by the winding. Check the other exciter winding in the same
way. Residual AC voltage lower than listed below will
indicate a faulty winding.
RESIDUAL AG VOLTAGES (Each exciter winding)
5.0 KW E11 • E22 AND E31 • E42_ 5·6 VAG
#50 • #9 AND #50 • #9_ 7 • 9 VAG
7.0KW E11 • E22 AND E31 • E4L_ 5·6 VAG
#50 • #9 AND #50 • #9 _ 7 • 9 VAC
THERE SHOULD BE NO
CONTINUITY BETWEEN LEADS
50HZ AND #9 TO CASE
GROUNDS
/ '
./
MEASURING VOLTAGE /~
GENERATOR RUNNING"
MECCALTE MODEL
50Hz 60Hz
9
.
~
COLISEUM MODEL
CAPACITOR
C1
E11r'. E
E~21
•
~E22
EWl
CAPACITOR
MEASURE THE RESISTANCE
VALUE OF THE EXCITER
WINDINGS BETWEEN THE
· 7
. . . . TESTING WINDING LEADS
MAIN STATOR WINDING RESISTANCE
LESS THAN ONE OHM FOR EACH WINDING GROUP
FOR NO CONTINUITY
END LEADS OF EACH WINDING
TO METAL CASE
EngInes & Generators
70
MAIN STATOR RESIDUAL VOLTAGE
LINE TO NEUTRAL 4-6 AC VOLTS
(THIS INDICATES GOOD STATOR WINDINGS)