What is the reason for the undervoltage fault alarm shutdown of the diesel generator set?

Q: What causes the diesel generator set under-voltage fault alarm shutdown?

1, generator regulator plate failure
May be due to changes in environmental factors, the AVR regulator parameters are no longer applicable, need to be readjusted, in general, non-parallel diesel units basically will not have this problem, because the parameters of the regulator is a fixed value (400V), generally can not be adjusted, only for parallel units may have this problem, because the AVR regulator in parallel is based on the main bus voltage for Adjustment, it is not set in stone, at this time, the parallel device generally has a regulating signal sent to the AVR regulator, this situation either check the regulating signal has not been connected to the wrong, or try to use electronic controls (parallel device, regulator, etc.) to re-regulate the voltage quickly when the power is on.

2, generator winding on the varistor or rectifier bridge diode damage

3, diesel engine generator speed control problem

Diesel engine speed control points electronic governor and mechanical speed control, if the mechanical speed control, then there is a control oil and oil pump mechanism on the diesel engine, speed control lever on both sides of the distribution of a speed limit (high speed) top bar and speed control top bar, start running 20S that is reported low voltage, I do not know if the voltage and frequency is not always on, if it is not always on, may be the speed is not on the cause, you can adjust the speed control top bar Try, but all diesel engine set failure, there is generally a major fault, the main fault is solved, resulting in a series of secondary faults followed by the solution.

4, voltage sampling line is loose

Voltage sampling line is loose, that is certainly not measured voltage.

5, ground fault

If the line out of the three-phase grounding, then the voltage and current is very low, this time the main check grounding discharge device (such as ground knife) is not closed or grounded.

The role of the varistor is: over-voltage fault occurs when the varistor conducts to lower the voltage, if the varistor is broken or conductive for other reasons, then it is conceivable that the voltage must be very low, rectifier bridge has six diodes, the rectified DC power supply to supply the regulator and excitation devices, if the rectifier bridge diode is destroyed, the role of the regulator and excitation devices will be greatly reduced.

6, remanent magnetism

If the generator does not have remanent magnetism, then the generator voltage system at the beginning of the build up, for this problem, we need to clear the generator AVR regulator excitation output is how much V voltage, and then the excitation output line connected to the corresponding voltage source for magnetization (voltage type to correspond, polarity do not reverse).

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