Westerbeke 7.0 KW BGC -60Hz Technical Manual page 140

Checking Stator Windings for the 4.5 KW BCG and 7.0 KW BCG
Group # 1 - Measure resistance value between terminal with lead # 1, and terminal with lead # 3.
(Check that there is no continuity of Group
# 1
windings to the case ground.)
Group #2 - Measure resistance value between terminal with lead # 4, and terminal with lead # 6.
(Check that there is no continuity of Group #2 windings to the case ground.)
Checking Stator Windings for the 7.0 KW BCGA
Group # 1 - Measure resistance value between terminal with lead # 1, and terminal with lead # 2.
(Check that there is no continuity of Group # 1 windings to the case ground.)
Group #2 - Measure resistance value between terminal with lead # 4, and terminal with lead # 5.
(Check that there is no continuity of Group #2 windings to the case ground.)
Check for a possible short between the two groups of stator windings by placing one lead of the
ohmmeter on the terminal with stator lead #1 and the other ohmmeter lead on the terminal with stator
lead # 4. There should be no continuity between the two groups of stator windings.
C.
Exciter Windings
4.5 KW BCG: 1.9 ohm 7.0 KW BCG
&
BCGA: 2.2 ohm
An AC voltage is induced in these windings by the rotating field. (Residual voltage measured between
#9 and the 50 hertz leads or the #9 and the 60 hertz leads for the 7.0 BCGA model unplugged from
the capacitor.) This residual voltage must be present for the exciter circuit to function. Do not unplug
capacitor leads while the generator is operating. The residual voltage is 14 -16 volts AC.
An AC voltage can be measured across
the capacitor(s) while the generator is
operating. This voltage may be as high
as 450 to 500 volts AC. This voltage
buildup is accomplished as the exciter
windings charge the capacitor(s) and
the capacitor(s) discharge back into the
exciter windings. This AC voltage read-
ing is taken between the #50 hertz con-
nector and the #9 connection or the
#60 hertz connector and #9 connec-
tion for the 7.0 BCGA between the
capacitor(s) while the generator is
operating at its rated hertz (60.5 - 61.5
for gasoline models, and 61.5 - 62.0 for
diesel models).
4.5 KW BCG 1 7.8 KW BCG
HZ
50
fC~PACITO'Sf
. H . £ 7 · 8 l
y~(4.5l
HZ
GO
7.8 KW BCGA
L~{P
£7.8 BCGAl
This flow of saturating AC voltage in the exciter windings produces a phase-imbalance type of field that
effects the rotating auxiliary windings: a beneficial result that produces good motor starting charac-
teristics for this type of generator.
To measure the resistance value of the exciter windings on the 4.5 and 7.0 BCG models, locate the #9
and the #50 hertz capacitor connections. On the 7.0 BCGA model itwould be the #60 hertz connection.
Westerbeke Generators 136