What is a brushless lawn mower?

brushless lawn mower

It’s time to buy a new mower, and you’ve decided to make the eco-friendly choice by buying electric. But not all electric lawn mowers are alike, and it can be hard to choose the right one. This article will cover one of the most common questions we get about electric mowers – what is a brushless lawn mower?

First, we’ll compare brushed and brushless mower motors to see how each one works. Then, we’ll cover the pros and cons of buying a brushless lawn mower. Finally, we’ll answer some of the most frequently asked questions about brushed and brushless mowers.

Brushless vs. Brushed Mower

A brushless lawn mower is an electric lawn mower that uses a specific type of DC electric motor. To understand what a brushless motor is and how it works, let’s start by exploring how DC electric motors work. Then, we’ll compare brushed and brushless mowers to help you understand the difference between the two.

A DC motor uses electricity and magnets to send power to your mower. Imagine a pair of ordinary round magnets. If you hold them close together, they will either attract or repel one another. If the positive side of one magnet faces the negative side of the other, they’ll be attracted to one another and snap together.

But if you flip one magnet over so that the opposite pole faces the other, the magnets will repel one another. Positive poles repel one another, as do negative poles. DC electric motors use this push and pull to operate. The difference between a brushed and brushless mower motor is just how they use the magnetic poles.

How Brushed Mowers Work

A brushed motor comprises three main components – fixed permanent magnets, an electromagnet inside a  spinning armature, and a brush. The fixed magnets are called the stator because they’re static, while the armature is called the rotor because it rotates.

The electromagnet inside the armature generates a magnetic field that interacts with the polarities of the fixed magnets. When it generates a positive charge, the armature is repelled by the positively charged fixed magnet and attracted by the negatively charged one.

However, that interaction will only rotate the armature 180 degrees – halfway. If it spun any further, the positively charged fixed magnet would just force it back where it came from. So, the metal brushes connect with electrodes on the armature in a brushed engine, flipping its polarity.

Each time the armature rotates 180 degrees, the brushes change the electromagnet’s polarity so that it can complete the revolution.

See how the electromagnets are on the outside - this is a brushless motor.
See how the electromagnets are on the outside – this is a brushless motor.

How Brushless Lawn Mowers Work

A brushless motor essentially inverts the conventional setup. The electromagnet is fixed to the stator in a brushless motor, while the permanent magnets are attached to the rotor. The electromagnet is then connected to a computer, which flips the charge of the electromagnet as it spins.

The computer connected to the electromagnet in a brushless motor takes the place of the brushes in a brushed engine. It keeps the motor rotating by changing the electromagnet’s polarity at regular intervals, so the fixed magnets always attract and repelling it efficiently.

Brushless Motors vs. Brushed: Pros and Cons

Now you know what a brushless lawn mower is and how it works differently compared to a brushed lawnmower. Now let’s talk about the many benefits of buying a brushless lawn mower, as well as some of the potential downsides that you should be aware of before making the investment.

Pros

So, what is a brushless lawn mower good for? A lot of things, as it turns out. A brushless lawn mower has several advantages over a brushed lawn mower. They’re quieter to use, they run cooler and more efficiently, and they require less routine maintenance than a brushed lawnmower.

Noise Level

As you can probably imagine, metal brushes scraping on metal surfaces can generate a lot of friction. At high speeds, the brushes generate sparks and electrical noise. Without the brushes, a brushless lawn mower is much quieter than a brushed lawn mower, making it more pleasant to use, too.

Smart Power Usage

For several reasons, a brushless mower is more efficient than a brushed mower. First, all that friction generated by the brushes saps power from the motor and converts it to heat. A brushless motor increases the mower’s power efficiency from as low as 60 percent to as high as 90 percent. That translates to more mowing on one battery charge.

They’re sometimes also called intelligent motors because they’re more responsive and adaptable than mechanical brush motors. A computer controls the electromagnet that keeps the rotor spinning in a brushless motor, which means it only generates as much power as it needs in a given moment, rather than generating too much and wasting it.

Finally, brushless mowers can generate power more efficiently than their brushed counterparts. The coils on a brushless motor are on the outside of the rotor, which helps it generate more torque than a brushed motor. These three factors combine to make a brushless motor more power-efficient than a brushed one.

Runs Cooler

The friction from the brushes in a brushed lawnmower generates a lot of heat, which is a common cause of electric mowers overheating. Without the brushes, a brushless lawn mower produces less heat, staying cooler for longer so you can get more mowing done.

Reduced Maintenance

It should come as no surprise that heat and friction are generally bad for motors. Brushed mowers require frequent maintenance to replace worn-down brushes and repair damage caused by high running temperatures and frequent overheating.

Brushless motors, on the other hand, require much less frequent maintenance to keep running in tip-top condition. They don’t have any brushes to replace, and the other parts don’t need repair or replacement as often because there’s less friction and heat to damage them.

Cons

Of course, no power tool is perfect, and brushless motors also have certain drawbacks. The most significant downside to buying a brushless motor is the expense, both in terms of the purchase price and maintenance cost. Here’s what you should be aware of before buying a brushless lawn mower.

Upfront Price

A brushless motor is more complicated and expensive to build than a brushed motor, which means that brushless lawn mowers tend to cost more up front than a brushed mower. You can buy a new battery-powered lawn mower with a brushed motor for under $150, while the least expensive brushless mower is over $250.

Costly Repairs

Yes, we did say that brushless mowers demand less maintenance than brushed mowers, but they still need work done occasionally, and when they do, it’s more expensive. The parts and build are more complex than a brushed motor, which means they’re more expensive and require more labor.

Still, the total maintenance cost over the life of a brushless mower is significantly lower than the cost of maintaining a brushed mower. While each service visit will cost more with a brushless mower, a brushed mower requires five to ten times more frequent maintenance.

Vibration

The heavy, fixed magnets on the rotor of a brushless motor can cause the mower to vibrate annoyingly at low speeds, but increasing the speed fixes the problem.

Likewise, the variable timing of the motor means it can sometimes sync up with the frequency of other parts of the mower, which amplifies the vibration. Again, adjusting the speed up or down seems to fix this problem.

Final Thoughts

So what is a brushless lawn mower? It’s an ultra-efficient electric mower that runs cooler and quieter than older, brushed models. They’re more expensive to buy upfront, which is a definite downside, but they cost less in the long run because you’ll save money on regular maintenance.

A brushless lawn mower is one of the most valuable investments you can make in your lawn and garden equipment. They’re better for the environment, cause less noise pollution, and are easier to maintain from year to year. Let us know in the comments if you have any further thoughts or questions about brushless lawn mowers!

Frequently Asked Questions (FAQs)

Here are a couple of additional questions we often get about brushless lawnmowers.

Are brushless lawnmowers worth the extra money?

Yes, absolutely. Brushless mowers cost more money upfront, but you’ll save money in the long run compared to other mowers because they require less routine maintenance and run more efficiently.

Do brushless mowers wear out?

All machines wear out eventually, but brushless motors are less susceptible to wear and tear, which means they last longer than other mowers and don’t need to be maintained or repaired as often.

How long will a brushless motor last?

The longevity of a motor is measured in hours. Brushed motors generally last less than 3,000 hours, and the brushes are the most frequent cause of failure. On the other hand, brushless motors often last over 10,000 hours because there are no brushes to fail.

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