Inverter vs Transformer Welder – How To Choose The Right Option

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Since inverter-style welders can onto the market around 30 years ago, there has long been a debate among the purists of the welding community and those willing to accept change.

Nevertheless, as you will find out throughout this article, there are not a “best” type only different uses.

An Inverter Welder is a product that was created as a result of the evolution of the welder.

There are a lot of similarities and differences between an Inverter welder and Transformer Welders. 

Still, to better understand the two and decide which one to pick for you and your needs, you need to know precisely how they work.

With so many different types of welders on the market today, it can be hard to know what is the best choice for your needs.

The two main types are inverter welder and transformer welders. 

You can use either type to weld mild steel and aluminum. Both types can also weld various kinds of stainless steel, but you can use only the transformer type for welding aluminum oxides. 

The most significant difference between the two is how they are powered.

With that said, let’s dive into the specifics.

What Are Transformers?

A transformer is an electrical device that transfers electricity from one circuit to another in the electrical world. In order to transform the power, transformers are made up of two coils of wire. 

The coil on the input side (input) is called primary winding, and it takes power from incoming line voltage (typically alternating current or AC). 

The coil on the output side is called secondary winding, and it transforms the input power into a lower voltage for easier use with consumer products.

A transformer helps make it possible to provide electricity across long distances using low-voltage alternating current (AC) electricity. 

Transformers generally consist of two coils with wire wrapped around them: an “input” primary coil and an “output” secondary coil. 

The primary coil is connected to the line voltage and the secondary coil to a load.

In AC power transmission lines at tens of miles long, the voltage can be so high that it is not safe or economical to connect small loads over the line directly. 

Instead, electrical transformers are used to drop the voltage from thousands of volts for transmission across long distances down to a level that can be handled by distribution lines and used safely in homes and businesses. 

Transformers work on a principle called induction, the changing of energy from one form into another, using coils of wire wound around the iron core material.

Transformer Powered Welding Machines

Inverter vs Transformer Welder - How To Choose The Right Option 1

In transformer-style welding power supplies, alternating currents with medium voltages are converted into high currents at low voltages, typically between 15-20 volts on an open circuit and between 55 and 590 amps. 

More expensive machines use rectifiers to convert AC to DC.

With this system, the welder can adjust the output current by adjusting the distance between the primary and secondary winding.

Machines of this style tend to be the least expensive.

However, this lower cost often comes at the expense of higher bulk and mass because it operates at a power grid frequency of 50 or 60 Hz.

Transformers that operate at low frequencies must have a higher magnetic inductance than they need to avoid excessive shunt currents. 

History of Transformers

To understand the history of the transformer, you must first understand the discovery of induction.

Michael Faraday and Joseph Henry independently discovered the principle of electromagnetic induction, the operation of a transformer, in 1831 and 1832.

Faraday created the first closed-core toroidal transformer by winding an iron ring with two coils of wire.

Only by applying individual pulses of current to his transformer did he discover a connection between the turns ratio and EMF.

When to Use a Transformer Welder

A transformer style of welder is the most common type due to its lower costs and ease of use.

They usually have a higher duty cycle than inverter models, which means you can use them for heavy-duty welding jobs.

Another benefit comes in the form of experience. They have been used for far longer than inverter models, and therefore, more is known about them.

For professionals and serious amateurs, it is often wise to stick with what you know.

Transformer Mig Welders Options

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What are invertors?

Since insulated gate bipolar transistors were invented, arc welding load has been capable of being handled by a switched-mode power supply. 

They rectify the electrical power by switching it from the utility into DC, then invert it using a step-down transformer to generate the desired welding voltage or current. 

A switching frequency of up to 10 kHz is typically used. 

Despite the high switching frequency requiring sophisticated components and circuits, the step-down transformer is drastically reduced in bulk cost since the number of magnetic elements necessary for achieving a given power level shrinks rapidly with an increased switching frequency. 

You can also incorporate power control and overload protection on the inverter circuitry. 

Welders that rely upon high-frequency inverters will typically have higher accuracy and more precise control of variable parameters than machines not using inverters.

History of Inverters

A DC-to-AC power conversion system was invented and used mainly between the late nineteenth century and the mid-twentieth century, which relied on rotary converters or motor-generator sets.

Along with gas-filled tubes, the vacuum tube played an increasingly important role in inverter circuits during the first half of the twentieth century. The thyratron was the most widely used type of tube.

Former AC-to-DC converters were used in-line with a generator dynamo when connected directly to AC-powered induction or synchronous motors, which required the reverse connection of the dynamo’s commutator to provide DC power. 

When to Use an Inverter Welding Machine

Inverter vs Transformer Welder - How To Choose The Right Option 2

So with that covered, why would you want to use an inverter welder?

Welders utilizing inverter technology perform significantly better than conventional welders. 

An excellent example of this is when stick welding. Welders find that welding is far more convenient because it is far easier to flow with the arc than fighting it. 

Inverter welding machines are popular because of the high open-circuit voltages, anti-sticking features, and arc-force they feature. 

Thin materials are a perfect example of why an inverter welder works better than conventional stick welders.

They provide nearly infinite amperage adjustments as well as very stable arcs with an electrode welding rod.

What Are The Benefits Of Using An Inverter Welder?

There are several benefits over transformer powered welders, including:

Improved Efficiency

You can adjust weld bead thickness with an inverter welding machine. 

A welder that uses an inverter improves the weld’s appearance while also maintaining the quality of the weld.

Inverter welding’s mechanism is efficient, staying cool even during the long-term operation. They usually use less metal in the filter, reducing heat input and providing greater productivity.

This can result in more significant savings for a welder. Cost-saving is beneficial if you weld for a living.

Compact Designs

As a result of the power supply being smaller, inverter models are far more compact than their transformer siblings.

Portability is ideal for those who transport their machines around to their places of work. It is also beneficial for amateurs that want something of a smaller size rather than dedicating an entire garage to the art of welding.

You Can Use Generator Power

Due to their efficiency, inverter welding machines are much more viable when used in conjunction with portable generators than traditional transformer machines. 

Inverter Mig Welders

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What Is The Debate Really About?

In one word: reliability!

The transformer machine has focused on much attention for nearly a century, while inverter machines have only received a similar amount of attention for the last 30 years. 

Nevertheless, In recent years, the gap between transformer and inverter products has decreased quite a bit.

As mentioned earlier, transformer machines have been a mainstay of welders all around the world for decades. This creates a bias towards that type of power supply.

However, with more and more inverter-style welders being created, they are fast becoming the welder of choice due to the numerous benefits they hold.

Inverter vs Transformer: When To Use Them

A transformer may be best if:

  • You have dedicated welding set up in your home or workshop. I.e., you have one location that you do all of your welding.
  • You favor or only need on the process.
  • Simplicity is your working ethos!

An inverter may be best if:

  • You need or desire portability.
  • Your work requires many different processes throughout the day.
  • You are an amateur welder and want flexibility.

If you will be welding different types and thicknesses of metal.

Frequently Asked Questions

Which welding machine is better, an inverter or a transformer?

It depends on your work process and what type of welding you do. Inverter models are more portable and can handle many different functions, but transformer models are more straightforward and have less to go wrong.

What are the most reliable brands of portable inverter welding?

Any of the well-known models such as a Miller inverter welder or a Lincoln inverter arc welder are best. You will get reliable warranties, lots of knowledge online, and access to add ons and spare parts.

What is the difference between a transformer and an inverter?

As discussed in this article, the main difference is the power supply and how it handles it. Transformers transform energy by using coils of wire wound around an iron core material. Inverters use a step down to get the preferred current of voltage from the machine.

Are inverter welders better than transformer welders?

Again, it depends on your needs. However, more and more people are switching to inverter-type welders due to the portability and flexibility inherent in their design. Nevertheless, transformer-powered models are still the most popular due to the sheer amount of power they can produce and the reliability of over a century of use.


An inverter welder is a welder that uses an inverter instead of a traditional transformer to convert the welding machine’s AC output to a DC output for the welding process. 

Both can be used in a TIG welder or a MIG welder.

Inverter welders are becoming increasingly popular as their technology advances, and they become less expensive.

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