Troubleshooting; Generator - Kubota WSM J Series Workshop Manual

J SERIES, WSM

[4] TROUBLESHOOTING

(1) Generator

NOTE

• In order to replace the parts in safety, remove negative terminal of battery so as to prevent the battery and
the parts from short-circuiting.
• To avoid errors on delivery of spare parts, all information marked on nameplates should be supplied on
parts orders, in particular model and serial number of the alternator. Also give the parts numbers from the
parts list.
(A) Evident Physical Defects (Overheating, Noise, Vibrations...)
Fault
Excessive overheating of
bearing (temp. of bearing
over 80 C (176 F))
(With or without
abnormal bearing noise).
Excessive overheating of
alternator frame
(temperature 30 C (8 F)
above ambient).
Excessive vibration and
humming noise coming
from the alternator.
Alternator damaged by a
significant impact which
is followed by humming
and vibration.
Smoke, sparks of flames
issuing from the
alternator.
Action
Replace bearing.
Check
• Air inlets and outlets
of alternator.
• Measuring equipment
(Voltmeter-Ammeter).
• Ambient temperature.
Stop the gen-set and
check the installation and
others.
Start up with no-load: if
humming persists...
Stop the gen-set
immediately.
Stop the gen-set
immediately.
Origin of fault
• If the bearing has turned blue or if the grease has
turned black,change the bearing.
• Bearing race badly locked (moving in its housing).
• Bracket misalignment.
• Air flow (inlet-outlet) partially clogged or hot air is
being recycled either from alternator or prime mover.
• Alternator overloaded.
• Fan belt slips.
• Three phase alternator is single phase loaded in
excess of acceptable level.
• Short-circuit in the alternator stator.
• Short-circuit in external circuit.
• Break or deterioration in the coupling.
• Break or twist in shaft extension.
• Shifting or short-circuit of the main field winding.
• Bursting or unlocking of the fan.
• Diode burnt, regulator, rectifier bridge damaged.
• Short-circuit in external circuit (including wiring
between alternator and control board).
• Object fallen into the machine.
• Short-circuit or flash in stator winding
S-4
GENERAL
W11912080
KiSC issued 10, 2016 A