TOYAMA TDMG25 Guia Del Propietario página 35

transformer (4 or 6 wire generators) or
sensing module (PCB).
AVR fault
Connections are loose, broken or
corroded.
Engine governor is unstable (hunting). Test engine speed stability with a frequency
AVR stability control is incorrectly set. Inspect links of AVR stability. Adjust the
Connections are loose, broken or
Unstable
corroded.
voltage
(no load)
Intermittent earth (low resistance of
windings insulation)
AVR components are broken or
corroded.
Fault or vibration of panel voltmeter
Unbalanced Fault of main stator windings
voltage
(on -load)
4.4.2 Self-excited AVR - ON LOAD
Trouble
symptom
Low engine speed
Under frequency protection (UFRO)
circuit activated.
Low
No power supply from main stator to AVR Test the AVR sensing supply feedback.
voltage
（on
AVR fault
load）
Fault of windings or rotating diodes
Voltage drop between generator and
load, due to I
be worse during current surges (e.g.
motor starting).
Table 4-5 Fault Finding: Self-excited AVR-On Load
The probable reason
2
R losses in the cable. It will
Replace AVR and re-test.
Inspect all terminals of auxiliary board.
Inspect AVR push-on terminals.
Repair, or replace if necessary.
meter or tachometer. Sometimes this problem
will be cleared when load is applied.
stability potentiometer.
Inspect all terminals of auxiliary board.
Inspect AVR push-on terminals.
Repair, or replace if necessary.
Test the insulation resistance of all windings.
Replace AVR and re-test.
Test voltage at generator terminals with a
multimeter.
Test the main stator windings.
Corrective action
Test speed with tachometer. Adjust governor
control to nominal speed.
Inspect UFRO led at AVR. If it is lit, UFRO is
activated, indicating low speed. Adjust engine
speed, to within -1% to +4% of nominal.
Replace AVR and re-test.
Test windings or rotating diodes.
Test voltage at both ends of the cables at full
load. In severe cases, a larger diameter cable
is need.
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