Sensored vs. Sensorless Brushless Motor: What’s the Real Difference?

You may know about brushless motors. They have a lot of power and they last a long time. But you might have seen that there are two kinds: sensored and sensorless. This article will help you understand the difference in a simple way. Knowing this will help you choose the right motor for your RC car, drone, or other project. You will learn which motor gives you a smoother start. You will also learn which one is better for high speed. This guide will help you know a lot so you can make a good choice.

What is a Brushless Motor Anyway?

Before we talk about the difference, let’s look at what a brushless motor is. A brushless motor is a special kind of electric motor. It doesn’t have small parts called “brushes”. These parts can wear out over time. This means the motor lasts a lot longer. It also gives you more power. These motors are used a lot in things that need high speed and good power. For example, they are in RC cars, boats, and drones.

You need a smart controller to make a brushless motor spin. This controller is called an ESC, which is short for Electronic Speed Controller. The ESC sends quick bursts of electric current to the motor. It sends this current in a certain order. This makes the motor’s rotor spin. The motor’s speed comes from how fast the ESC sends these electric bursts. More bursts mean more speed and a higher RPM. The ESC is like the brain for the motor.

A brushless motor has two main parts. The outside part that stays still is the stator. It has coils of copper wire. The inside part that spins around is the rotor. It has strong magnets. The ESC sends current to the coils on the stator. This makes a magnetic field that pushes and pulls the magnets on the rotor. This is what makes the motor spin and create power. When the ESC controls this well, the motor runs very smoothly.

What is Special About a Sensored Brushless Motor?

A sensored brushless motor has a special part inside of it. This part is a sensor. Its job is to watch the motor’s rotor. To be exact, it tells the ESC right where the position of the rotor is all the time. This is very important for smooth control. The ESC gets this information right away. So, it knows the perfect time to send the next bit of current.

The most common kind of sensor is called a Hall effect sensor. A sensored brushless motor will have a few of these small Hall sensors. They feel the magnetic field of the rotor’s magnets when they go by. A sensored motor has an extra cable with a small group of wires. This cable plugs into the ESC. It is used to send the Hall sensor data. This feedback makes the ESC very smart. It can start the motor very smoothly from a full stop with no shaking.

The ESC always has perfect timing. Because of this, the sensored motor uses its power very well. The ESC can send the right amount of current at just the right moment. This is the main advantage of a sensored brushless motor. You can think of it like a dance partner who knows your next step before you even do it. The Hall sensor lets the ESC know the position of the rotor. This makes everything work together perfectly. The Hall sensors create a steady stream of feedback.

How Does a Sensorless Brushless Motor Do Its Job?

A sensorless brushless motor is a lot simpler. Just like its name says, it has no sensor. So, how does the ESC know where the rotor is? It uses a clever trick. When a motor is spinning, it also works like a small power generator. It makes a very small amount of voltage in the wires that are not getting power at that second. This is called Back EMF. That is short for Back Electromotive Force.

The ESC for a sensorless brushless motor is made to listen for this Back EMF. By feeling the Back EMF, the ESC can make a good guess about the rotor position. This works very well when the motor is already spinning at a medium or high speed. The faster the motor spins, the stronger the Back EMF signal becomes. This makes it easier for the ESC to figure out where the rotor is. This way of working is smart. It also saves money because you do not need to buy a Hall sensor.

A problem can come up when the motor is moving at a very low speed. It can also happen when it starts from a full stop. When the motor isn’t spinning, it does not make any Back EMF. The ESC has no idea where the rotor is. So, it sends out some blind bursts of current just to get the motor to move. This can cause a shaky or stuttering feeling as the motor tries to start. As soon as it gets a little bit of speed, the ESC can feel the Back EMF. Then it can take over and make it run smoothly. This is the main downside of a sensorless brushless motor.

Sensored vs. Sensorless Brushless: Why Does It Matter?

The biggest difference between these two motor types is all about what the ESC knows. A sensored motor system lets the ESC know the exact position of the rotor all the time. It gets this information sent right to it from a Hall sensor. A sensorless motor system makes the ESC guess the position of the rotor. It does this by listening for the Back EMF.

This one difference changes how everything works. It changes how the motor starts. It changes how it runs at a low speed. And it changes how many parts are in the system. Think about it like this: a sensored motor is like driving with a GPS map that shows your exact spot. A sensorless motor is like driving by just looking at road signs. You can get where you are going both ways. But the GPS is a lot more exact. This is very helpful when you need to make tiny, careful moves.

So, when you see the words sensored vs sensorless brushless, it’s all about this main difference in how they talk to the ESC. The ESC has to know where the rotor is so it can spin it the right way. One way gives the ESC direct information. The other way makes the ESC figure it out by itself. The way you plan to use the motor will help you choose the best type for your needs.

Which One is a Better Choice for High-Speed Fun?

When all you want is pure, very high speed, a sensorless brushless motor is often the best pick. At a high RPM, the motor is spinning so fast that the ESC has a very strong and clear Back EMF signal to follow. The shaking that can happen at low speeds is not a problem. This is because you get past that stage very quickly on your way to high speed.

A sensorless motor is also more simple and tough. There is no fragile sensor board or extra wires that can break. If you have a crash at high speed, there are fewer parts that can get damage. This makes them a stronger choice for things like speed-run cars, airplanes, or racing boats. The whole system has less moving parts. This can mean it is more reliable when you are pushing for the highest RPM.

So, if you want the fastest top speed you can get and you don’t need careful control when you are stopped, a sensorless brushless motor is probably the better choice for you. It is made for high RPM and it can handle rough use. Not having a sensor is not a bad thing at high speed. Some people even say it is a good thing because there is one less part that can cause a breakdown.

Do I Need a Sensored Motor for Smooth Slow Motion?

Yes! If you need smooth and exact control at a very low speed, a sensored motor is the one you want. The Hall sensor gives the ESC constant feedback on the position of the rotor. This lets the ESC send very smooth power, even when the motor is hardly turning. You can have a very exact and easy start from a total stop.

This kind of smooth motion is very important in some hobbies. A great example is RC rock crawling. In rock crawling, you need to make very small, exact movements to climb over things. A sensorless motor would shake and jerk, which would make it impossible to crawl slowly. With a sensored motor, you can give it just a little bit of throttle. The wheels will turn slowly and smoothly. This gives you the control you must have.

A sensored motor also works much better when it has to start with a heavy load. The ESC can know the position of the rotor. Because of this, it can give full turning power right from zero RPM. A sensorless motor might have trouble or shake if you try to start it with a heavy load connected to it. For anything that needs a gentle start or exact low speed movement, a sensored motor is the better choice.

What Kind of ESC is Needed? A Look at Sensored and Sensorless.

The Electronic Speed Controller (ESC) is the brain. You have to match the ESC to your motor type. You cannot use the wrong one. This is a very important part of the sensored and sensorless choice. An ESC is made to work with one or both kinds of motors.

A sensored motor has an extra wire that comes out of it. This is the sensor cable. To use this sensor, you need a sensored motor ESC. This kind of ESC will have a special plug for the sensor cable. If you plug a sensored motor into an ESC made only for sensorless motors, it will still run. But it will run just like a sensorless motor. You will not gain any of the good things for low speed. This is because the ESC cannot read the Hall sensor.

Many new ESCs can work with both types. They are sometimes called “smart” ESCs. They can run both sensored and sensorless brushless motors. They have a sensor plug. If you plug a sensored motor into it, they will use the Hall sensor data. If you plug in a sensorless motor, or if the sensor breaks, they will switch to using Back EMF. It is always a good idea to check the details for the ESC to be sure it will work with your motor. A good ESC will also let you change settings to make your motor’s performance just right. The ESC has to know what it is working with.

What are the Good and Bad Points of a Sensored Brushless Motor?

Choosing a sensored brushless motor comes with a clear set of good points and bad points. Knowing these will help you see if it’s the right choice for you. The main advantage is its very smooth feeling.

Here is an easy table that shows the good and bad points:

The biggest reason to pick a sensored brushless motor is for its exact control. When you need to have total control over the motor’s speed, especially at a low speed, it is the best choice you can make. But, this exactness means there are more parts and a higher chance of something breaking due to the fragile sensor.

What are the Good and Bad Points of a Sensorless Brushless Motor?

A sensorless brushless motor is the tough, simple worker of the brushless world. It is made for pure speed and to last a long time. Its main advantage is how simple it is. This makes it very reliable for jobs with a lot of stress.

Here is a list of its good and bad points:

A sensorless brushless motor is a great pick when the things you care about most are high speed, simple design, and a lower price. It is a powerful and dependable choice for things that need to go fast. But, if your project needs a smooth start or careful low speed handling, you will not be happy with how it performs in those areas.

Sensored vs. Sensorless Brushless Motor: How Can I Pick One?

Now you know the difference. Making the choice is easy. The choice between a sensored vs sensorless brushless motor really comes down to one question: How are you going to use the motor? What you are doing is the key that helps you find the right answer. There is no one motor that is better for all jobs.

Think about what you need the most. Do you need perfect control at a very slow pace? Or do you need the fastest top speed you can get? For example, if you are building an RC rock crawler, you must have smooth low speed ability. The clear choice is a sensored motor. If you are building a drag racing car to get the highest possible speed, a tough and simple sensorless motor is the better choice.

Last, think about where you will be and what ESC you have. If your car or truck will be in wet or dirty places, the simpler sensorless motor might be a more safe choice because there is no sensor that can get damage. Also, check your ESC to be sure it can work with the type of motor you want. By answering these questions, you can be sure you are choosing the right motor. This will help you gain the best performance for your project. An ESC that can handle both sensored and sensorless gives you the most choices.

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• The main difference is how the ESC finds out the position of the rotor.
• Sensored Motor: Uses a Hall sensor to send information right to the ESC. This gives you a smooth start and perfect low speed control.
• Sensorless Motor: The ESC uses Back EMF to guess where the rotor is. This is great for high speed but can shake at low speed.
• Choose a Sensored Motor for: Rock crawlers, trial trucks, or anything that needs exact, slow motion.
• Choose a Sensorless Motor for: Racing, bashing, boats, airplanes, and anything where top speed matters most.
• Always match your motor to your ESC. A sensored motor needs a sensored ESC to give you all its good points.