Generators Won't Produce Electricity, How to do?
by Starlight Generator dieselgeneratortechThis article is mainly written to analyse the reasons that may lead to generator won't generate electricity as well as the solutions.
Working principle of generator
Generator works by moving
electrical conductors through a magnetic field. If your generator doesn’t have
magnets, it won’t produce electricity. The magnetic field is created by taking
some of the generator output voltage and converting it to DC and feeding it to
a coil to make an electro magnet.
Nowadays, the generator degree of
automation is high, the control circuit is also complex, thus, some faults may
occur when the generator set is at work, which directly affect the normal power
supply operation of the unit. So during the normal operation of the genset,
except monitoring and analyzing the data on system instrument, it is also
necessary to observe whether the parameters of the generator on each instrument
are within the normal range or not.
Why a generator won’t produce
electricity? This is a hot topic that many users care about. Next, I will
analyse the reasons for you.
1. The residual magnetism of the
generator core is disappeared or too weak.
The residual magnetism can be
lost naturally when the genset is placed too long or it can also happen from
running a generator with no load for too long. However, for the new genset, the
residual magnetism can be lost due to a long distance transportation vibration.
Thus, it will cause the remanence voltage of generator is disappeared or less
than normal remanence voltage value, namely, the remanence line voltage is less
than 10V, the remanence phase voltage is less than 6V. Because the stator of
synchronous generator, rotor, as well as AC exciter stator, and rotor core are
usually folded by adopting 1~1.5mm thick silicon steel sheet. After excitation
vibration, the residual magnetism is easy to disappear or weaken. When the
residual magnetism is lost, the generator will produce no power at start-up.
2. Excitation circuit wiring
error
The polarity of the excitation
winding is reversed. After electrifying, the magnetic field produced by the
field winding current is counteracted with the residual magnetism, resulting in
the disappearance of the remanence. In addition, when measuring the DC
resistance of the excitation winding or testing the automatic voltage regulator
AVR, without paying attention to the polarity, which will also cause the core
remanence to disappear.
3. Excitation circuit is blocked
In the generator excitation
circuit, the electrical contact is bad or the wiring head of each electrical
component is loose, the lead wire is broken, causing the circuit to be
interrupted, and the generator excitation winding has no excitation current.
4. Circuit for DC side of rotary
rectifier is interrupted
Due to the interruption of
circuit for DC side of rotary rectifier, therefore, after the AC exciter is
rectified by the rotary rectifier, the excitation current supplied to the
excitation winding can not be sent into the excitation winding, resulting in AC
synchronous generator can not generate electricity.
5. AC exciter fault, no output
voltage
The generator can’t produce
electricity due to AC exciter failure, so that the excitation winding of the AC
synchronous generator has no excitation current.
6. Generator excitation winding
is broken or grounded, resulting in the generator has no excitation current or
the excitation current is minimal.
Solution
1. When the residual magnetism of
the generator core disappears, magnetizing treatment shall be carried out.
The magnetizing method:For the
self-excited generator, usually using extra battery or dry battery, using its
positive and negative poles to supply electricity for a short time towards the
leading-out terminal of the excitation winding. However, be sure to recognize
the polarity of DC power supply and excitation winding clearly, namely, the
positive pole of the DC power supply is connected to the positive pole of the
excitation winding, and the negative pole of the DC power supply is connected
to the negative pole of the excitation winding. If the control panel of diesel
generator set is equipped with magnetizing circuit, the toggle switch should be
turned to “magnetizing” position, which can magnetize the AC exciter.
2. Excitation circuit wiring
error, correct it after searching.
3. Use multi-meter ohm block to
find the excitation winding broken line and connect it. For the failure caused
by poor contact, polish the surface oxide layer with find sand cloth, the loose
connection bolt and nut shall be firm.
4. Ground and broken line fault
of excitation winding. Use 500V ohmmeter to check the ground insulation of the
excitation winding, find out the ground point, use multi-meter to find out the
broken line and restore it.
Hope the above methods can help
your restore your generator output power. If it still fails. you need to
replace the automatic voltage regulator as it may be damaged.
We supply multiple brand of generator such as Cummins, Perkins, Volvo, Deutz, Ricardo, Doosan Daewoo, Yuchai, Shangchai, Weichai, Wuxi, etc.
Email us at: sales@dieselgeneratortech.com
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Created on Nov 20th 2017 23:48. Viewed 402 times.