Onan NHE Service Manual

TROUBLESHOOTING THE GENERATOR
Trouble
No
AC Output
Voltage
Note: This
condition may
cause the
generator set to
stop when the
Start switch is
released.
AC Output
Voltage Too Low
Or
Too High
Noisy Generator
Possible Cause
1. Open circuit breaker
2. Open circuit between brush
block and CR4 rectifier.
3. Brushes stuck in holder or
not making good contact with
slip rings
4. Defective CR4 bridge
rectifier
5. Open, grounded, or short
circuit in rotor, stator, or
transformer
1. Engine governor incorrectly
adjusted
-'
*2. Open diode in CR4 bridge
rectifier
*3. Brushes worn or not making
good contact with slip
rings
4. If generator frequency is
within specified limits but
voltage is incorrect,
transformer is incorrectly
connected or defective.
"5. Open, grounded, or short
circuit in rotor, stator,
or transformer
*causes low AC output voltage
1. Loose brush holder
2. Worn generator end bearing
3. Rotor and stator rubbing
together due to: a) varnish
lumps, orb) rotor
misaligned with crankshaft
Corrective Action
1 )
Locate cause of overload
and correct as required.
Reset breaker
2) Check for continuity and
correct if circuit is open
3) Release brushes if jammed
in holder. Clean slip
rings if dirty.
4) Test rectifier and replace
if defective
5) Test each component for
open, grounded, or shorted
windings and replace if
defective.
Refer to Governor
section
Test CR4 rectifier and
replace if defective
Check length of brushes
and replace if worn
excessively. Clean or
replace slip rings.
Adjust tap connections on
transformer secondary
windings to obtain correct
voltage. Replace
transformer if voltage cannot
be corrected with adjustments.
Test each component for
open, grounded,
or shorted
windings and replace if
defective.
1) Tighten brush holder
2) Replace end bearing
3a) Check for varnish lumps
between rotor and stator and
remove
as required
3b) Follow specified assembly
procedures to correct rotor
to crankshaft alignment.
.
-.
8-6
Redistribution or publication of this document
by any means, is strictly prohibited.
Redistribution or publication of this document
by any means, is strictly prohibited.

Onan NHE Specifications

General

Brand	Onan
Model	NHE
Category	Portable Generator
Language	English