3 Symptoms of a faulty AVR in a generator


Without doubt, an Automatic Voltage Regulator (AVR) is one of the most crucial electrical components in a generator. It efficiently maintains the terminal voltage of you generator and enables it to operate smoothly however, they are not immune to being faulty.

Just like any other electrical component in a generator, an Automatic Voltage Regulators is bound to lose their efficiency and effectiveness over a period of time. Unfortunately, this also affects the overall performance of the generator and hinders it from operating efficiently throughout. For sure, it can get frustrating when the AVR of your generator is faulty because it makes the generator to produce less power than it should whenever it is running.

There are a number of symptoms that show the AVR of your generator is faulty. This includes, pre- mature burnout of electrical components, low power output and a malfunctioning instrument cluster. Therefore, you are required to call a professional to have a look at your generator in the event you notice any of these symptoms.

Symptoms of a faulty AVR in a generator

Pre-mature burnout of electrical components

At times you might experience pre-mature burning out of electrical appliances that are plugged into the generator in your home or business premises. When this happens, the first thing you should have a look at is the AVR in your generator then conduct some few tests to make sure it is functioning optimally. Excessive voltage output will cause your electrical appliances too high and too quick which in turn will reduce their useful life.

For sure, this will make you incur losses as you will have to eventually replace all the electrical appliances that have been damaged.

Too little voltage

Experiencing little voltage output might sound safer than having excessive voltage output but this is not the case. As a matter of fact low voltage output is equally as dangerous as high voltage if not more dangerous. Low voltage tends to make the motor overwork itself as it tries to draw extra current in order to deliver the expected power output. When there is low voltage in your generator, amperage will increase. This is a potential hazard because the internals of the engine of the generator may overheat and melt. Low voltage indicates current that is inadequately controlled and one of the main causes of this is a faulty AVR.

Malfunctioning instrument cluster

The Automatic Voltage Regulator is what powers up the instrument cluster of the generator. Once the instrument cluster starts malfunctioning, it is possible that your generator’s AVR is faulty. You will therefore have problems in reading fuel levels, oil pressure and other important information from your generator’s cluster.

Effects of running your generator with a faulty AVR

AVR Failure

With a dying AVR, all the above signs will be displayed and if ignored, your AVR will automatically seize functioning. It is wise to replace your AVR as soon as you experience any of the signs because by the time the AVR stops working it will have already caused catastrophic damage to the electrical components of your generator.

Automatic Voltage Regulators can be damaged in a number of ways such as unstable generator speed, current overload, power surges, short circuits and corrosion

Causes of AVR damage

Unstable engine speed of the generator

When the motor in your generator has unstable revolutions per minute, your Automatic Voltage Regulator will work twice as hard in order to compensate for the unstable rotations. This will cause damage to your AVR in the long run. Therefore, you should immediately call a professional to check your generator if you sense that the generator is not running right.

Short Circuit

This is a common problem when it comes to electrical components and short circuits prove to be fatal to both your generator and the AVR. Regular occurrences of short circuits will damage the AVR in your generator.


When a generator is given more electric load than it is supposed to handle, there will be a decrease in motor speed which in turn causes the voltage to drop. The AVR will constantly try to maintain the set voltage. This overworks the AVR and if it happens constantly then the AVR is bound to fail sooner than expected.

Large Power Surges

If the load and power experienced by your generator is large enough, there are high chances that the Automatic Voltage Regulator will experience a shock. This is because the AVR will be unable to stabilize the voltage due to sudden changes of large power size.

On the brighter side, there are prevention measures to each of the mentioned causes. The table below summarizes the causes of damage to an AVR and its prevention measures.

Prevention Measures
Unstable Engine Speed
You should ensure the motor of the generator is always running at its recommended speed as this will prolong the service life of the AVR in your generator.
Short Circuit
You should ensure that all the electrical appliances in your home are installed professionally. You should also perform regular checks on your electric circuits for any naked wires and make sure there is good isolation resistance.
You should carefully go through your user manual and get to know the maximum load your generator can potentially handle then avoid exceeding the maximum load.
Large Power Surges
Avoid exposing your generator to excessive load as well as excessive power.


A faulty AVR can cause permanent damage to your generator if not sorted as soon as possible. When working with a tight budget you can always try to repair your current AVR. However, it is always advisable to get a brand new one for optimum performance to increase the useful life of your generator.


What happens if the Automatic Voltage Regulator is removed from a generator?

There will be a lot of fluctuations in the output power.

Can an automatic Voltage Regulator be by-passed?

Yes, it is possible to by-pass the AVR in your generator but it is not recommended.