What Is Generator AVR? Working Principle, Its Importance, Features, And All Other Information


Last Updated on March 17, 2024 by Ali Hamza

What is Generator AVR?

An Automatic Voltage Regulator that controls voltages and removes the fluctuation from the voltages. When the supply system goes variations in voltages, these types of voltages are harmful to the appliance and damage the equipment of the power system. Automatic Voltage Regulators (AVR) for generators to regulate voltages and prevent fluctuations.

The manufacturer’s AVR is at different places. That helps in controlling the voltages fluctuation at each end. This article will discuss the working principle, its importance, and all other information you want to know.

What is the Working Principle of AVR?

The basic principle of voltage regulation is to find the error in voltages. The first transformer provides the voltages, then rectifies and compares them with reference voltages. If there is a difference between fixed voltages and reference voltages regulator highlights its difference. The generator output voltage of the stabilizer operating under varying loads is regulated. If the generators operate in parallel, they can also distribute the loads among them. Parallel generators help with the voltage drop.

An automatic voltage regulator(AVR) not only helps to adjust the voltages to safe levels, but it also protects against electrical surges and generator overload. As a result, the generator responds to excesses effectively. Simply put, it accepts a range of varying voltages as input and produces a fixed value.

Importance of AVR

A generator’s voltages are maintained through automatic voltage regulation because if the voltages are not constant, the generator’s performance may be impacted. The generator-powered utilities, machinery, and equipment may experience problems. Due to fluctuating voltage, a spark can occur. Uncontrolled voltage can cause a spark. The automatic voltage regulator ensures the lifetime of the appliances since it ensures that the load current is constant. An automatic voltage regulator helps undo the damage these alterations have caused.

Functions of AVR

The main tasks of AVR are given below:

  • It can control the voltages and maintain the rectified and reference voltages.
  • Distributing the load between parallel alternators lowers the high voltage.
  • Even during the most significant fluctuations, it retains its composure and does not comment. The voltage stays constant in this fashion.
  • Under fault conditions, it enhances the system’s excitation.
  • The AVR regulates the over-voltage that develops due to the load’s rapid loss.

How to choose an Automatic Voltage Regulator?

To ensure that you choose the most suitable AVR for your application, we have listed the top features of high-quality AVRs below.

Voltage Regulation

Ideal voltage regulation is attained when the voltage value equals all electrical equipment loads. Voltage control may be influenced by several factors, including the motor starter, the size, type, and reactance of the wires and cables, the circuit design, and the power factor. Despite these obstacles, voltage regulation must be chosen with an accuracy of 1%.

Input Voltage Range

The first step in choosing the best automatic voltage regulator is to determine your input voltage range. Because line voltages typically increase less frequently than they decrease, the input voltage range must be wide and fluctuating.

This feature enables more low correction rather than concentrating on high correction. Additionally, it makes it simpler to design the automatic voltage regulator to work in either buck mode or boost mode, allowing it to correct the voltage to its maximum in challenging circumstances.

Low Impedance

Impedance is a component’s resistance to the flow of electrical current and is expressed in ohms. Low impedance is the goal of an automatic voltage regulator. Interactions between the source impedance and the load current can lead to low voltage, harmonic distortion, and voltage imbalance. The best case scenario would be to prevent all of this if your automatic voltage regulator had minimal impedance. 

 Load Compatibility

Voltage regulation solutions must be compatible with the load in order to guarantee the operation of the specified load. In the same way, don’t interfere with any extra bags that are connected to the same power source. High-performance automatic voltage regulators must be able to regulate loads with large starting currents, high peak factors, and large power factors.

Voltage Accuracy

An automatic voltage regulator’s primary purpose is to increase voltage accuracy. The requirement for a critical load impacts voltage accuracy. Automatic voltage regulators often function in circuits when changing the conductor’s size is useless for regulating voltage. For an automated voltage regulator to function independently in demanding situations, it must have the five characteristics listed above. Transient suppression should also be considered a critical feature when voltage impulses, surges, and transients constitute a significant threat.

What part of the generator houses an AVR?

One of three places is where the generator AVR is typically found. It could be in the main control box of the generator, behind the back cover of the alternator, or (usually only on very tiny portable units) in the alternator’s terminal box.


Automatic regulating voltages are a vital part of the generator. Without AVR, the voltages will not remain stable, and voltages will affect the generator’s performance. To ensure the implementation of generator quality, AVR must be preferred.

When the load or temperature changes, a quality AVR ensures that the generator continues to run for a long time. An AVR would protect against disturbance of the process. And would take all reasonable steps to protect the connected electrical appliances from harm.


  • What causes generator AVR failure?

It was determined that the generator driving motor’s decreased performance was the root cause of the AVR damage because its rotation became unstable when the engine was under electric load. The voltage fluctuates, that damage the AVR.

  • Does AVR save electricity?

No. An AVR controls the input voltage that goes into your appliance. Although it was not designed to do so, it will ultimately save you money since it will protect your equipment from harm brought on by voltage fluctuations.