Table 2-2. Generator Set Troubleshooting (Cont)
Malfunction
Probable cause
Corrective action
e.
Fuel level
e.
Terminals 4 and 16 of A5.
relay K8.
NOTE
Start the generator set and open the protection
bypass switch S7.
Remove the jumpers installed in
c, d, and e above. If the set stops when one of the
jumpers is removed, that component is defective and
must be replaced.
If the set shuts down when the
jumper in step d is removed test OP and WT and
replace the defective component.
32.
Paralleling
DC relay control
With set stopped, check resistance
lights, DS4
circuit assembly
between A5 terminals 7 and 8 for
and/or DS5,
(A5) defective.
DS5, and terminals 19 and 20 for
will not light
DS4. Resistance should be 7500
with S6 in
Ohms ±5.0 percent. If no continuity,
parallel
replace dc relay board (A5) (para 8-6
position
and 8-7).
33.
Improper governor
Current transformer
Measure resistance of R23, R24,
operation (i. e.,
resistor board (A7)
and R25 on A7 (located in pre-
load sensing)
defective.
cise relay box on Class 1, Mode
1 sets - in set special box on
other sets). Replace any resistor
that does not read 7.5 ohms ±0.5
percent (fig. 8-2 and 8-3).
34.
Generator
Governor resistor
set hunts
Check capacitor (C1) on A6, between
board capacitor (Cl )
pins 5 and 6. Replace a defective
defective
(Class I only)
capacitor. (60 mfd non-polarized)
(fig. 8-4 and 8-5).
35.
Main AC con-
a.
Defective short
a.
Check relay K13. Replace if
tactor (CB2)
circuit relay
defective (para 8-6 and 8-7).
will not close
K13.
b.
Defective overload
b.
Check relay K14. Replace if
reload relay K14.
defective.
c.
Defective reverse
Check relay K15. Replace if
power relay K15.
c“
defective (para 8-6 and 8-7).
d.
Defective under-
d.
Check relay K11. Replace if
voltage relay K11.
defective. (para 8-6 and
(Class I only)
8-7).
e.
Defective under-
e.
Check relay K12. Replace if
frequency
defective. (para 8-6 and
relay K12.
8-7).
f.
Defective permis-
f.
Check relay K16. Replace if
sive paralleling
defective (para 8-6 and 8-7).
relay K16.
g.
Defective contactor
g.
Check switch S3. Replace if
switch S3.
defective. (para 6-2).
2-18
