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Brushless Motors: Sensored vs. Sensorless

There are all sorts of motors that qualify as brushless motors, but a significant point of difference between brushless motor designs used in RC truck applications is sensoreless vs. sensored operation.

Explaining the difference is best done by defining what sensored means. All brushless motors used in RC applications have three main wires, but sensored motors have an addition multi-wire loom that connects the “brains” of the speed control to the motor. On the motor end of the loom are sensors that tell the speed control a number of things, but most importantly the exact position of the rotor within the motor through three Hall Effect sensors.

Sensorless motors simply do not have sensors inside the motor—hence the name sensorless. They determine the likely position of the rotor based on feedback called back-EMF. EMF is short for Electromotive Force. Back-EMF also known as counter-EMF is essentially the resistance or voltage pushing back against the current flowing to the motor.

Logical question: why do you need sensors? Sensors are not required as is evident by the fact that sensorless motors work, but sensors do perform a valuable function. When the speed control knows the rotors specific location, it can better control throttle feel. This is noticed in a smooth controllable throttle feel and a truck that doesn’t hesitate at low speeds. Sensored motor manufacturers also state sensored designs have more startup torque or power off the line. The sensors can also tell the speed control if there is anything wrong with the motor. The speed control can use this information to shutdown the motor and avoid damage.

The natural follow up question: if sensors are so beneficial, why don’t all motors have them? One of the most noticeable downsides of sensored motors is that the sensor loom can break or come loose. Many speed controls will cease to power the motor if the sensors are not detected. Another downside is cost. More parts simply mean higher costs. In contrast, it is said sensorless motors are more efficient at high speeds.


Cogging is a noticeable hesitation at low speeds, often when starting from a stop. Technically, this is the incorrect term and engineers use the word cogging differently, but the point is brushless motors can exhibit a very noticeable stutter at low speeds. Speed control manufacturers that favor sensorless designs go to great lengths with their programming to eliminate any stutter.

Tips for Reducing Cogging:
> Install a smaller pinion gear
> Upgrade to high quality, higher C-rating batteries
> Use higher voltage batteries

Hybrid Controllers
In addition to strictly sensorless and strictly sensored controllers, there are two types of hybrid brushless controls. One type, such as the Traxxas Velineon VXL-3s, will automatically switch to sensored mode when a sensor loom is installed and sensors are detected. Another type of hybrid, such as Tekin RX8, switches from sensored at startup and low speed speeds to sensorless at high speeds.


Recommended Applications
For general bashing, you can use either sensored or sensorless. For rock crawling, a sensored system is mandatory. For racing, sensored or a hybrid controller that switches from sensored to sensorless is recommended.


Find out more information about brushless motors and Kv vs. turns here.


Special thanks to Novak for image of sensored endbell






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  1. I run a sct late model class at our local track that everyone runs the same motor witch is a traxxas vileneon…I am running a mamba max pro esc and even tried my tekin rs esc…neither of them is getting any speed…some of the guys running same motor is hauling butt…I have done all I can think of…it’s like I’m only getting half power…I have changed batteries…radios…please help

    1. If you have changed all of that, I assume you have changed the motor too (make sure you don’t have bum motor). Try this: Set your radio all the default settings and make sure your radio’s end points for throttle are set to the maximum and then recalibrate/setup the speed control to the radio per the instructions. Also, make sure you talk to the race director or track official about boost or timing. If boost or timing advance is allowed (non “blink” mode) and those guys are using boost that would/could explain the speed difference. Last, try some big changes in gearing to see how your setup reacts–just watch motor temps with each change. Check out this article on gearing.

      1. Hey there…. My name is frank. I just picked up a viper sensorless
        Brushless combo. Guys at hobby store swore it was good for the track.
        And the cogging is awful. Just ran for first time today. I’m kinda disappointed
        I put it in sc10 4×4. Is it just the wrong motor ?

        1. You got steered wrong–in my opinion. I do not suggest sensorless for track use at all. Viper is a great brand for racing, but most of their systems are sensored and thus a”good for the track.”

          1. It’s seems that way….. Is it completely out of question to use it at track?
            I’m kinda pissed cuz we all race together and they own the shop I go to
            Is it dangerous or damaging to car? Figure you can trust
            The owner of a hobby shop

          2. The cogging won’t hurt anything, but it’s irritating and ruins slow speed throttle feel. Experiment with gearing to see if you can diminish the cogging. Good luck. Since Viper is predominantly a racing company, they probably thought it would be good for the track.

          3. So throw some rally tires on it and make it a bashed then? Haha
            Thank you for the help. I realized today that ya can’t trust em all

  2. Now i get it. thanks for explaining the differences. i just kept hearing sensorless was faster and therfor better

  3. Matt,
    I have a neu castle 1410 that I am using in a non-traditional way. I am using it to drive an auger system in a model grain bin I built for farm shows. Can I use a regulated AC to DC converter to run the unit? I have a smaller motor that this works fine on but that one does not have enough torque to drive my system. Can I use a speed controller(i have one for my smaller motor) to drive this neu castle motor? I am not sure of the specs I would need(voltage, amps) but I was hoping you might be able to assist me so that I do not have to spend $200-$300.

    Thank you,

    1. As you know, Castle Creations works with Neu to make that motor, so your best source of info would be the tech folks at Castle Creations. They do list that motor as intended for use with 2S or 7.4 volts with a maximum of 3S or 11.1V. Castle Creations recommends its Sidewinder SV3 speed control and Mamba Max Pro–$120 and $127, respectively. I’d go with the Mamba Max Pro, but run it off 2S.

  4. Hi there. I thought of buying the Scorpion RS-3420 4.5T motor. I got to know that this motor is very fast and that it is sensored. Here’s the link – http://www.scorpionsystem.com/catalog/car/motors_2/rs-3420/rs_3420_45t/

    I wanted to find a waterproof ESC for this which is compatible with the sensored motor so I thought of buying the Leopard 80A Waterproof ESC For 1/10 RC (http://www.asiatees.com/display?id=57936&brand=Miscellaneous&model=All)

    Will it be compatible and will I be able to use this sensored things with it and what sort of battery would support the two ?
    Pls let me know

  5. Thank you much for the info. I’m running the Tekin RX8 system in my Ofna GTP2e and really found this helpful…

  6. Amazing, needed to do research about brushless motors because I was upgrading from a brushed to brushless. Very helpful and explained very clearly thank you!

  7. Hi my name is Jake and I’m using a neumotor 1110 3/y sensored motor, and I want to remove the sensor all together to make it to the normal motor again can it be done? and how.

    Thank you,

    1. Can you mix and match Sensored products between brands? I have an XTM racing Sensored ESC and would like use a Reedy Sensored Motor.

  8. Hey Matt, great article on the merits of sensorless vs sensored BLDC motors. I’m an entrepreneur with a patent-pending on a motorized device that uses a novel motor as its drive means. We require assistance on how to get accurate position sensing in our unique application using a sensorless means. I’m wondering if there’s anyone in your vast rolodex that you think could help us. (You are welcome to email me his name if you’d prefer not to post it publicly.) Thanks!

  9. Can one tell visually if a motor is sensored or sensorless? If not, is the default when selling motors that they are sensorless and that it would be noted specifically that the motor is sensored?

    Can a sensored motor be used with an ESC that is meant for a sensorless motor? How about vice versa?

    Thank you!

    1. Yes, you can visually tell a sensored motor will have a small rectangular port on the end bell area. This is where the sensor wires plug into.

      We only recommend using sensored with sensored and vice versa. Some speed controls are both sensored and sensorless operation, but you have to check with each brand and model.

  10. I have a traxxas 4×4 slash that I took the esc and motor out and put into another truck. I purchased the hobbywing ezun max10 not noticing that it is sensorless. Is this going to be a problem?

  11. Hi Matt, I’m considering RC off road and I believe I’ll get into short track (not sure yet). However, I’m retired and would rather buy a good vehicle and TX that I can grow in to, versus a beginner set. I’m interested in quality, performance, durability and ease of maintenance. I stumbled on your article since I was researching brushless motors. Would you mind providing me with a couple options for RC vehicles and TXs that would fit my requirements? My research is pointing to Traxxas and Losi, but the reviews are split and maybe there is something else out there. Hmm?

  12. Matt, did you receive the comment I submitted to you on this website earlier today? I don’t see it listed. Hmm?

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