The Ultimate 10 Step Guide To Choosing A Voltage Regulator (Buyer’s Checklist Included)

Choosing the perfect Automatic Voltage Regulator (AVR) can be a confusing process for some. Whether you’re a facility manager, an electrical designer or even a consultant, selecting the perfect brand and type of AVR could be one of the most crucial factors in the success of your project. 


This step-by-step guide is purposefully designed to ensure you have checked all the boxes in your buying journey, with considerations of your requirements, budget, pro tips of technical specifications to watch out for, and more…

Below is a road map that will take you one step closer to your electrical project goals. 

Now let’s get you started.

Bonus: Read to the end to get a comprehensive checklist, created to help you find the best Automatic Voltage Regulator that suits your operational needs.


Be Crystal Clear About Your Applications & Objectives

Having a stabilised and constant voltage supply is key to unlocking optimal performance in your electrical system. No matter the scale of your operations, maximising your uptime should always be top priority. Examples of your objectives can be:

As some electrical challenges (in both industrial and commercial applications) are more complex than others, you can create your goals accordingly to match them.


If you’re looking for detailed resources for solutions to solve specific electrical problems like severe voltage fluctuations or voltage drops, get a copy of your complimentary whitepapers here (full 22-page reports packed with quantitative and qualitative research).


Identify The Volatility Of Your Incoming Voltage Range

In some setups, there could be substantial voltage drops in the incoming AC supply. You’ll need to choose an automatic voltage regulator that could reliably compensate for your specific input voltage range (wide or narrow).

Depending on how drastic the load change in your operations are, inherent voltage fluctuations cause voltage levels to be low during the day (high load) and extremely high in the night (low load). A wider input voltage range might require an AVR voltage tolerance of up to ​​±40%, so your equipment continuously enjoys an optimised and stabilised output voltage supply. After all, the goal is for your high value loads to receive total voltage protection, no matter how erratic the input voltage can be.


Know Your Type

Not all Automatic Voltage Regulators are created equally. The AVR market provides a range of designs, built for the same purpose of overcoming voltage anomalies. However, different designs – come with different pros & cons.

Some common designs include:

  • Servo Electronic – Time tested design, high voltage accuracy, most widely used in both industrial & commercial applications, best value for money.
  • Magnetic Induction – Uncompromising durability and dependability, high in manufacturing costs but ideal for rugged use and harsh environments.
  • Static (Tap Switching) – Suitable for non-critical applications, quick to build, cheaper cost.
  • Solid State (Ferroresonant) – Highly reliable (no moving parts), ideal for single phase application.

For an in-depth overview of the different types of AVR designs, this blog article provides diagrams and illustrations that highlight all the features and benefits to help you easily understand the working principle of an automatic voltage stabiliser.


Choose Quality Over Quantity. EVERY. SINGLE. TIME.

Remember the last time you bought something that was absolutely needed to solve a pain point, only having to return it the next day because it didn’t work as well as you’d expect it to?

Much like anything important in life, what is it worth to you to be able to solve your frustrations – once and for all?

Is price the single biggest driving factor that dictates your buying decision? If you’re anything like us, we believe in making our investments worth every cent. Look for trusted brands in the market with a proven track record and case studies so you can save yourself money, time, resources and ultimately, solving your voltage challenges, permanently.

Beware of products that cut corners by using recycled copper wires to lower the price. As time goes by, these products will very soon cost more to use and maintain (due to low efficiency and high maintenance) or even worse, fail prematurely. For a list of key players in the market, here’s a Yahoo! News Report highlighting a list of recommended Key Players in the AVR market.


Dig Deep And Ask Yourself: “How Much Maintenance Do I REALLY Want To Deal With?”

A question you should ask yourself before deciding on an AVR, what you’re looking for is a “Plug-and-Forget” voltage regulating solution that consistently works as you’d expect it to – no matter the complexity and volatility of your incoming voltage supply. Anything that involves having to schedule the manufacturer’s support team to conduct serving or maintenance, is simply too troublesome.

Choose a reliable voltage regulator that requires minimal maintenance (ocular inspections), or even better, a virtually maintenance-free AVR (magnetic induction design) – so you can have a peace of mind, knowing you’re always in full control of your operations.


Understand What UltraPrecise Voltage Regulation Means For Your Operations

Total voltage protection for mission critical loads and high-value sensitive electronics is essential. The goal is to turn severe over-voltage levels and voltage sags – into a precise and stable output voltage supply, which ensures peak performance and consistency from your equipment.

Pro Tip: Servo Electronic Voltage Regulators deliver stepless and highly accurate voltage regulation of up to ±0.5% – compared to Static Tap Switching designs that offer only ±5% voltage accuracy.


Eliminate Harmful Voltage Anomalies, FAST.

Slow and steady isn’t always the game to play when it comes to solving electrical problems, especially if the objective is to protect your precious uptime. What you need is a voltage regulating solution that stabilises erratic incoming voltages – instantly and permanently.

For immediate results, look for specifications with ultra fast voltage regulation response time of 1.5ms or less


For 3-Phase AC Applications, Have Your Voltage Supply Regulated – Independently

In a three phase power, it is common to find that one phase has a “higher” voltage level while another has a “lower” voltage level. In this situation, regulating the voltage level of all three phases using a single control method does not produce optimal results that your load needs. Independent phase regulation is often the preferred method since it typically provides better phase-to-phase voltage level balance. Large differences in voltage levels from phase-to-phase can cause premature failure of electrical devices due to overheating or vibrations.


Opt For Higher Efficiency

The Automatic Voltage Regulator’s efficiency is the measure of how much power is wasted by the regulator hence, the higher the efficiency, the better. To ensure maximum performance and productivity of your operations, look for efficiency that’s more than 97%.


Consider The Environment Of Your Installation Site

For installation sites with harsher conditions (dusty or saline environments) and rugged industrial applications, consider a design that’s robust and engineered for total voltage protection. For outdoor usage, a minimum of IP54 enclosure is ideal.

For simple voltage stabilisation and regular commercial use cases, go with a safe design like a Servo Electronic Based Voltage Regulator, which has historically dominated the market for being the best value for money, combined with high reliability.

Confused about your options? We understand that finding the best voltage regulating solution can be a challenge. So before you commit anything, ensure that your research is completely thorough by having an overview of the best Automatic Voltage Regulators available right now

Any burning questions?

No worries, here’s a bonus FAQ section just for you.

Frequently Asked Questions

A: There are 4 commonly used types of Automatic Voltage Regulator (AVR) designed for commercial and industrial applications:

  • Servo Electronic
  • Magnetic Induction
  • Static (Tap Switching)
  • Solid State (Ferroresonant)

Each design has its pros and cons. While Servo Electronic based Voltage Stabilisers have mainly dominated the market, the ever-growing demand for uncompromising reliability and maximum durability in voltage protection has caused an unsurprising shift towards the Magnetic Induction design.

Static tap switching design (thyristor based) is favoured by non-critical projects that are desperately constrained by budgets. When technical specifications are written under non-stringent requirements (e.g. voltage output of ±10%), cheaper prices may be preferred over quality.

Solid State Design (ferroresonant) is highly dependable. With no moving parts, the ferroresonant voltage stabiliser is not subject to mechanical wear and tear. Due to its nature, it is typically suitable for single phase applications.

To learn more on which design is ideal for your application, read our comprehensive blog article (11min read) to find out more.

A: An Automatic Voltage Regulator is designed to maintain the output voltage stabilised, from no-load to full, regardless of load change. Whether the input voltage is low during the daytime (due to high load), and high in the night (due to low load), the AVR continuously and automatically regulates – future proofing against facility expansions. In other words, your output voltage will remain constant regardless of load change.

A: It depends on which power system you’re using. If your load is on a single phase system, use a single phase Automatic Voltage Regulator. Single phase volt units are in use with a single phase power system, which is common in many homes.


However, if you’re using a three-phase load, or want to regulate a three-phase power system, use a three-phase Automatic Voltage Regulator.


A: Automatic Voltage Regulators are designed and built typically with input voltage tolerance from ±10% up to ±40% (of the set output voltage).


For example in a 3-phase system:
Your minimum input voltage: 348V
Your maximum input voltage: 444V
Your set output voltage: 400V

The optimum choice of protection would be an AVR with ±15% input voltage tolerance because it effectively maintains a stable output voltage for fluctuating input voltages between 340V and 460V.

Depending on your operations, if the bigger the required input voltage tolerance,  the higher the cost of the AVR will be. Hence, it is essential to find the perfect balance between effectiveness and price.

A: Regulator sizing is based on the maximum load, with a small amount for future expansion (10% to 25% extra) and some derating for certain occasions. The buyer’s checklist below will assist you in making a decision of what size of AVR is the best option for your operations.


Pro tip: If you’re powering a single equipment with high inrush current, like a wielder or a X-ray, choose a regulator with a rating higher than the equipment’s full load rating (e.g. 30% to 50% extra). Take note of the rated voltage, frequency, number of phases and current or KVA, which can be found on the equipment’s nameplate or manufacturer’s catalog.


When in doubt, contact the equipment’s manufacturer if you’re planning to use an AVR for a single system which consists of equipments such as a CAT scanner or X-ray apparatus.

A: What is guaranteed to work best for you should be an option that meets your requirements, your budget and operations. It also has to be a solution which meets your goals.

Pro tip: If your goal is to ensure power backup, certainly an Automatic Voltage Regulator isn’t going to solve your problem. Instead what you should be looking for is an Uninterruptible Power Supply (UPS). If you’re looking for voltage protection for sensitive electronics and communication equipment, an ideal solution will be an AC Power Line Conditioner. And finally if your goal is to eliminate voltage drop or simply comply with voltage drop limits, the optimal solution will be a Voltage Drop Compensator

In Conclusion

In conclusion, now that you’re well equipped with these 10 Steps to consider before purchasing your Automatic Voltage Regulator, we hope that this article has given you the clarity and insights to help you in your journey to hugely improving your uptime. 

And even if you’re simply doing your comparison shopping, feel free to Download this AVR Buyer’s Checklist as your guide to find the most ideal voltage solution for your needs. 

Have you decided on the best AVR for your needs? 😉

P.S. Need more professional advice? Contact us to get your complimentary consultation, where we systematically review your requirements and provide you with a customised solution to your needs. If our 40 years of experience in the Automatic Voltage Regulator market has taught us anything, we’ve found that the best solution – is always one that’s both on point and on budget.

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