TOYAMA TDMG25 Guia Del Propietario página 36

Unbalanced load
Leading power factor load (capacitor
High
banks).
voltage
(on load)
Reverse
transformer
Engine governor is unstable (hunting)
Leading power factor load caused by
Unstable
power factor correction capacitors
voltage
(on load)
Fluctuations of load current (motor
starting, or reciprocating loads)
AVR stability
incorrectly.
Large speed droop of the engine.
AVR UFRO protection is activated.
Unbalanced load
Parallel droop circuit incorrectly adjusted,
or requires shorting switch foe single
running.
Poor
voltage
regulation
(on load ) Voltage drop between generator and
load, due to I
be worse during current surges (e.g.
motor starting).
Fault of rectifier or excitation winding
AVR under frequency protection circuit
(UFRO) activated.
Poor Engine governor is sticking or slow to
voltage respond.
response activated.
to load
of parallel droop
control is
2
R losses in the cable. It will
AVR UFRO protection
Test voltages on all phases. If it is
unbalanced,
phases.
Test excitation volts between X+(F1) and
XX-(F2). A leading power factor will give an
abnormally low DC excitation. Remove power
factor correction capacitors from system at
low load.
current Check for droop reversal.
Test engine speed stability with a frequency
meter or tachometer for governor hunting, or
cyclic irregularities in the engine.
Isolate the power factor correction capacitors
before sufficient inductive load has been
applied.
Test the load current on a stable supply, i.e.
mains.
adjusted Adjust AVR control until voltage is stable.
Test the speed droop from no load to full load
is not larger than 4%. Inspect AVR led. If it is
lit, increase engine speed.
Test voltages and load currents on all
phases. If they are unbalanced, re-distribute
load between phases.
The droop circuit will give additional voltage
droop of -3% at full load 0.8 power factor. For
single running machines this can be removed
by fitting a shorting switch across the droop
CT input, (S1-S2), on the AVR.
Test voltage at both ends of the cables at full
load. In severe cases, a larger diameter cable
is need.
Test rectifier or excitation winding.
Check UFRO led. If lit, UFRO is activated,
indicating low speed. Test speed with
tachometer and adjust to correct nominal
speed or frequency.
Check the performance of engine during
is application of load. Check whether AVR led is
lit during motor starting. Check whether AVR
DIP or DWELL circuits are activated. Adjust if
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re-distribute load between