Why is AVR of Generator Set Broken

by Generator D. Diesel Generator

Automatic voltage transformer regulator (AVR) is a sealed electronic device, which can control the magnetic field of the exciter and adjust the rectifier output power of the exciter armature, so as to control the magnetic field current of the main machine and stabilize the output voltage of the brushless generator. It has low frequency and no input signal protection device.

In addition, parallel compensation function is provided to meet the customer's demand for expanded capacity. Therefore, it is very important to maintain the voltage regulator (AVR).


What Cause Generator AVR Damage?

1.AVR circuit is composed of rectifier main circuit, voltage detection circuit and comparison control circuit. Excluding the possibility of damage caused by the quality of the original electrical components, in the whole AVR circuit, the working frequency of the main circuit and the comparison control circuit changes most frequently; the rectifier bridge of the main circuit and the transistor in the comparison circuit change more frequently, The damage ratio of AVR is more than 90%.

2.In view of the fact that the AVR on the imported generator belongs to non disassembly and repair parts, if it is damaged, it needs to be replaced. Therefore, we mainly analyze the causes of AVR damage on diesel generator. It is most important to avoid AVR damage as far as possible. As long as it is used properly, the service life of AVR can be improved. The more stable the generator voltage is, the smaller the variation frequency in AVR is; the smaller the switching action of transistor in comparison circuit is, The lower the probability of AVR damage.

diesel generator set

3.The output load is relatively stable. The smaller the variable frequency in AVR is, the smaller the switching action of transistors in the comparison circuit is, the smaller the probability of AVR damage is; the more stable the speed of diesel engine is, the smaller the oscillation impact of changing current on AVR; frequent "traveling block" and overload, and the large difference of three-phase load are the main reasons for AVR damage; the generator set with E, F, C fuel system is selected, the use of AVR will be more reliable due to the small frequency variation.


What should we do after generator AVR damaged?

Although AVR of generator belongs to non vulnerable parts, it causes abnormal damage due to various reasons. Under the condition that all parts from the engine to the generator are in good condition and the AVR can not generate electricity and is in a hurry to use electricity, we can adopt temporary emergency measures to solve the problem of urgent need of electricity.  

1.Cancel AVR plate, only use F1 and F2 as temporary excitation input.

2.With the help of the battery of the generator, an excitation switch and a 5W, 5K ohm rheostat are installed. When the engine reaches the rated speed, the switch is turned on, the voltage is established, and the rheostat is adjusted to set the voltage at about 420v. If there is a voltage regulator regulator regulator on the control panel of the generator, it is temporarily used to stabilize the voltage by changing the wiring.

3.Not all the above methods can be used for power supply under all conditions. The following conditions must be met in order to meet the requirements: A. load ≤ 70%; B. load ≤ 20%.

4.In this method, we should pay attention to whether the charging performance of the charger is good. If the charger can not be charged, add a 24 V transformer with a voltage of more than 20 A, and then use it in parallel with the battery, otherwise the battery will run out of power quickly.    


We are a manufacturer of diesel generator set in China, we have Cummins, Volvo, Perkins, Deutz, Shangchai, Yuchai, Weichai, Ricardo etc. Power range is from 20kw to 2500kw, if you have purchase plan, welcome to contact us by email

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About Generator D. Senior   Diesel Generator

99 connections, 1 recommendations, 626 honor points.
Joined APSense since, September 11th, 2017, From Jiangsu, China.

Created on Aug 13th 2020 01:17. Viewed 58 times.


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