Residual Voltage Check - Westerbeke 7.6 kw EDT Operator's Manual

7.6KW BT GENERATOR SINGLE PHASE
INTERNAL WIRING FOR
12
~'WD
DT GENERATOR
r-------,
I
C
I
r-------,
I
Ie)
1
AC
T
E
R
M
I
N
A
L
r--------------.
: 1
B :
:~
14
-
A
.1
I 1
•
I
I
1
!
1
1
. . . .
!
'
..
•
•
!
!
1
6
5
9
o
3
2
7
8
I
-t>I-
,
B
~4
31
I
I
I
C
I
L
1
~
I
1
1
I
•
1
2 .
....
B
L
o
C
K
-
I
2
I
I
3
l
==?"P= 1
L _____________
J
I
I 3 1
WHT/BLK
•
L
______ J
' "
L
.!13H--I--
~
J
@
"
G
ORANGE
+
AC
BLACK
DC
1<}-
GREEN
-
AC
YELLOW
RESIDUAL VOLTAGE CHECK
1 •. Residual Voltage 18 - 22 volts AC.
NOTE: The amount of no-load voltage produced by the
generator can be an indicator of where in the generator
the problem/fault may lie.
This voltage is the AC voltage produced by the generator
from magnetism in the exciter stator field. This voltage is
measured between the AC neutral and hot leg(s) with no-
load on the generator running at its hertz.
The presence of residual voltage is an indication that the
following generator components are OK:
1. Exciter Rotor (B-1 a, b, & c) & (B-2)
2. Rotating Field (B-3)
3. Main Stator (C-f& C-2)
4. Compound Transformer (D-I & D-2)
The fault lies in one or more of the following compo-
nents in the exciter circuit:
A. Exciter Stator (A· )
B. Bridge Rectifier (G)
C. Moon Stator Auxiliary Windings (C-3)
D. Compound Transformer Auxiliary Winding (0-3)
2. Twelve (12) volts DC excitation of the exciter stator
windings should cause the generator to produce between
125 - 135 volts AC between each hot lead and the neu-
tral. (Twelve volts DC is applied between the lifted
(+)
and
H
leads of the bridge rectifier,
+
to
+
and - to -.)
Correct voltage produced with twelve volts DC excitation
indicates the fault is in one or more of the above listed
components B,D "r·B, Iftlie generator does not produce
125 - 135 volts AC, then include A and C.
3. The absence of any voltage from the generator indicates a
fault with the moon stator windings C-I and C-2 andlor
the compound transformer windings D-I and D-2. Other
failed components that can produce this same no-voltage
output are the posi-resistor inthe exciter rotor and four or
"
z
~
. 1
WHT /GREEN
I
0
•
S
T
U
o
a. Apply 12 volt DC excitation to the exciter stator wind-
ings as explained in paragraph 2. A fault in \he main
stator andlor compound transformer windings such as a
short will cause the generator engine to load down and
the shorted windings to eventually produce smoke as
the excitation is continued.
4. Voltage output greater than residual and less than the
rated output indicates a fault in the exciter rotor/field B-1;
B-2, B-3. Excitation of the generator as explained in
paragraph 2 should produce a partial rise in voltage out-
put and, when removed, the voltage will return to the
original low output.
START MOTOR
EXCITING THE GENERATOR
WITH 12 VOLTS
KEEP THE EXCITER CIRCUIT
POLARITY CORRECT:
DC. 10 Baltery at Starter.
DC-Io Case Ground
FROM DC
{-J
more fail<il diodes mthe exciter rotor ..
1=.:'::;:'
"'" WESTERBEKE
NOTE: Current model bridge
rectifiers are configured
differently, but + and - are
still located at the corners.
Engines & Generators
39