What is the difference between a brushed and brushless?

You must be wondering whether brushless units are more efficient than brushed ones. Well, the answer is yes! There is no doubt about it. Let's now check out the pros and cons. It will help us understand why they are more efficient.
Brushless or Brushed Alternator

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What is the Difference Between a Brushed and Brushless?

Whether you want to power your home, business, or a seaside cottage, you’ll need a generator. Some people get confused when selecting the appropriate type of alternator. Don’t they know what the Difference is Between a Brushed and Brushless Alternator?

After reading this guide will acquire something about it. Besides that, you will also learn which one to choose for your needs.

So, without further ado, let’s not waste any more time and jump straight into the guide.

Brushed Alternator

In the following article, a brushed alternator (Next I will call their brush) has a coil connected to the engine’s rotor. The magnets are on the main shaft, which passes through the center of the rotor. Usually, this kind of alternator needs more amperage.

The field coils are shorted out by brushes that connect to slip rings on the armature. These brushes supply power to the rotor windings, i.e., electromagnetic waves. Which is around the rotor of an alternator.

brushed alternator

Why do generators have brushes?

Generators have brushes for two reasons. The first is that the generator has to produce a certain amount of power. That means that it must be able to handle a heavy load.

The second is that their need to maintain a steady voltage and frequency. It means constant speed output.

Brushless Alternator

This is the more modern type of alternator that lacks a brush assembly since it has no moving contacts. Two stationary field coils generate electricity using electronic components. A microprocessor usually controls the electronic part of this alternator.

A brushless is much more efficient in comparison to its brushed counterpart. It is because it eliminates the energy wasted in charging and replacing worn ones. 

Unlike a brushed unit, there are no carbon brushes that wear out over time. It means that the brushless produce a lot more power in a single unit.

How does a Brushless work?

A brushless alternator(Next I will call their brushless in the following article) generates AC voltage. It happens due to the rotating electromagnetic coils inside the alternator’s case. that connect to the rectifier and then change this alternating current into DC power.

You can charge your battery system if you have a brushless. But it may charge at a lower rate than a brushed one.

A brushless can produce a more stable and consistent voltage. It also works with the help of semiconductors, which is why its efficiency is higher.

In contrast to the brushless, the brushed ones aren’t that efficient. 

What is the Difference Between a Brushed and Brushless?

Now you may have a general idea of both types of generators/alternators. Let’s talk about the significant difference between the two types of them. The main difference is the carbon brushes.

On brushed, there are carbon brushes, as explained earlier. Yet, their counterparts, i.e., the brushless, lack carbon brushes. This feature makes the whole architecture different from each other.

It impacts the working principle of both devices along with their performance. Apart from that, it also affects the running duration.

Three-phase AC Generators

Brushed Pros and Cons

Let’s now have a look at the pros and cons of brushed. Understand why they are not as efficient as their brushless counterparts.


The first pro that comes to mind is that they are cheap. This means that if you don’t have a budget to buy a brushless unit, then you can go for a brushed one.

Also, they are durable and will last longer than their counterparts. There is no electronic component in these types. So the chances of it breaking down are meager, which makes them much more reliable as well.


First, a brush takes more amperage compared to its counterpart. Because it has carbon brushes that wear out over time. It means that the supply of power output will reduce over time. Besides, they also produce less power when compared to their brushless ones.

Brushless Pros and Cons

You must be wondering whether brushless units are more efficient than brushed ones. Well, the answer is yes! There is no doubt about it. Let’s now check out the pros and cons. It will help us understand why they are more efficient.


Since brushless do not have brushes in contact, they are more efficient. Besides, there is no wear and tear over time, which will last longer as well.

Besides that, as these units lack brushes, it produces more output. In other words, you can make a lot more power with a brushless team than a brushed one.

There aren’t any moving parts inside of it, which means that the chances of failure are meager. 

This makes them much more reliable as well. On top of that, there is no need for any periodic maintenance. 

These units also take less amperage, which increases their efficiency as well.


In comparison to a brushed unit, brushless is much more expensive because it has electronic components, such as a microprocessor.

It makes them much more complex when compared to the regular ones that we discussed before. Another con is that it increases the chances of power output failure.

Even though they are more efficient, they are still susceptible to damage. This means that if you want your alternator to work well, you need to install a high-quality one.

Brushless Alternator

Factors that Makes the Brushless Better

You may know the significant difference between both types of devices. Yet, there are still some things you should know.

Here are some of the main factors that make it better:

Increased Power to Loss Ratio

First of all, the brushless have a high power-to-loss ratio. It helps these to perform much better as compared to brushed. 

The unique construction of brushless units allows them to produce more power. This means that you will be able to get more benefits from that.

High Efficiency

The efficiency of a brushless is another factor that makes it better. The reason is that no brushes inside them.

It helps the generator to produce more output as compared to the brushed ones. It is because there is no energy loss due to friction. Moreover, it generates less heat during the action, which is an excellent thing. Having that said, the brushed produces much more heat. 


The longevity of a unit is another factor that makes it better than its brushed counterpart. Brushless don’t have a lot of friction during an action. On the side, the brushed alternators’ parts wear out due to constant contact with each other. 

What To Look For In A Brushless?

To make an informed decision, you must first know what to look for brushless alternators. You need to consider many things when looking for one, such as the amperage and the size.

Also, you must know the voltage. You can choose the one that is compatible with your needs.

Even though this unit might be more expensive than its brushed counterpart, it will still give you great value for money in the long run because there are no moving parts inside of it, and it is also more efficient.

When should you pick one over the other?

To pick a suitable device for your needs, you will need to consider various factors. First of all, is your budget. Brushed are usually cheaper as compared to brushless ones.

But, your generator should provide full-time emergency backup without any issue. For this purpose, the brushless is more reliable and robust. A good one such as the ST Series will be best for your power requirements.

But, if your needs are minor, you should go for compact options such as the BLG Series. Besides this, you will need to decide which brand you want to go with.

This is because some brands produce more reliable units as compared to others. At the end of the day, your needs will always be at the top priority.

Final Words

Comparing brush generators or brushless generators, which one is better? To be honest, It depends on your needs. What do you think?

If you enjoyed this article, feel free to post a comment below. Feel free to share it with your friends as well if you think that this may be helpful. 

For more information about brushless alternators, do check out our other articles too.

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Hey all, I'm Baymax Yan, working at a generator manufacturer and Having more than 15 years of experience in this field, and I belives that “learn and lives.” The sure thing is that I can often help my work. So I have created the blog to share all my knowledge with you. Hope my sharing helps!

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