After generator starts up, there is no voltage, the most possible reason is the generator has no
magnetic field.
Why
is there no magnetic filed in generator?
Fault phenomenon:
After standby generator set idle for a long period of time, when restart, there is no AC voltage
output. Measure the main output winding, and the voltage between phases is
"0" or lower than "5vac".
The
reason:
Generator has not been
used for a long time, resulting in losing remanence contained in iron core. The
excitation coil can't establish the proper magnetic field. At this time, the
generator set runs normally but does not generate voltage. This kind of fault
often occurs in new generator set, generator set stored in humid environment or
generator set not used for a long time.
How
to deal with no magnetic field problem of generator?
1.Check the main output
circuit of the generator to avoid the excitation cannot be established due to
the short circuit at the output end.
2.if there is excitation
and magnetization button, press the excitation and magnetization button.
3.If there is no
excitation button, use the battery to magnetize it. The specific method is:
a.Use 12V DC battery,
connect negative pole to "XX" terminal of AVR board, the positive
pole is connected to the "X" terminal of AVR through a diode.
b.Restart the generator
set and record the main stator output voltage, the voltage is close to the
rated voltage, or the voltage between P2-P3 of AVR terminal is 170-250V.
c.Shut down the unit,
then disconnect the battery power supply of "X" and "XX"
terminals, and restart the generator set. At this time, the generator set
should be able to operate normally. If there is still no voltage, it can be
considered that there is a problem with the generator set or AVR.
Here
is an other method of resolution:
First, look at the gloss
level of the two slip rings. If there is no lustre, rub it with emery cloth
until it becomes shiny. If still can not solve, use a very thin fuse and
connect the three-phase four wires on the generator randomly. Then start the
engine, the fuse will blow automatically, and the voltage will come up.
If you don't know the
diode, open one of the iron rings on the back cover of the generator, and you
can see two slip rings, then see the carbon sand. At this time, take a battery
of any size, start the generator and hold the positive and negative terminals
on the battery by hand, press and hold the two carbon sands corresponding to
the slip ring. Do not remove until the generator voltage increases.
If it still doesn't
work, exchange the positive and negative poles of the battery. If the voltage
disappears immediately after removal, it indicates the diode is broken. Replace
the diode.
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