
SEBU8088-06 121
Maintenance Section
Varistor - Test
3. Check the compr
essor wheel for cleanliness.
If only the blade side of the wheel is dirty, dirt
and/or moisture is passing through the air filtering
system. If oil
is found only on the back side of the
wheel, there is a possibility of a failed turbocharger
oil seal.
The presence of oil may be the result of extended
engine operation at low idle. The presence of oil
mayalsobeth
eresultofarestrictionofthelinefor
the inlet air (plugged air filters), which causes the
turbocharger to slobber.
4. Use a dial indicator to check the end clearance
on the shaft. If the measured end play is greater
than the Ser
vice Manual specifications, the
turbocharger should be repaired or replaced.
An end play measurement that is less than the
minimum Ser
vice Manual specifications could
indicate carbon buildup on the turbine wheel. The
turbocharger should be disassembled for cleaning
and for ins
pection if the measured end play is less
than the minimum Service Manual specifications.
5. Inspect th
e bore of the turbine housing for
corrosion.
6. Clean the
turbocharger housing with standard
shop solvents and a soft bristle brush.
7. Fasten th
e air inlet piping and the exhaust outlet
piping to the turbocharger housing.
i01494879
Varistor - Test
SMCS Code: 4466-081
g00677004
Illustra
tion 76
PMPE G enerator W iring Diagram
(CR1-CR6) Diodes
(CR7) Varistor
(L1) Exciter field (stator)
(L2) Exc ite r armat ure (ro t o r)
(L3) Main field (rotor)
(L4) Main arm ature (stator)
(L5) Pilot exciter armature
(PM) Permanent magnet
(RFA) Rotating field assem bly
(CST) Customer supplied transformer
Ohmmeter
An ohmmeter
canbeusedtocheckavaristor
(CR7). Place an ohmmeter across the varistor. The
resistance should be a minimum of 15000 ohms. If
the resist
ance is less than 15000 ohms, the varistor
is faulty.