Sensored vs Sensorless Brushless Motors

The world of Brushless motors can seem daunting to the beginner, with what seems like an endless array of options to choose from; motor size, number of turns, KV rating etc. There’s also another option that needs to be taken into consideration when choosing a Brushless Motor for your RC car, and that’s Sensored or Sensorless!

Venom Sensored Brushless Motor - Rated at 6.5 Turns. The timing of this motor can also be adjusted further by rotating the end bell of the motor.

What Is A Sensored Brushless Motor?

A sensored brushless motor has the usual three wires connecting it to the ESC (Electronic Speed Controller), plus an additional cable that sends feedback to the ESC enabling the ESC to adjust its output to get the very best performance from the motor. In particular, this feedback enables better levels of control at lower speeds, giving a much smoother and precise throttle response. With a sensored system, the ESC will always know the exact position of the rotor and will adjust its output accordingly. This is most essential when racing.

Having this extra Rotor position information allows the ESC to apply power to the correct rotor phase immediately, ensuring that no cogging (jeryky stuttering) occurs off the line or when applying the throttle as you leave the apex of a corner. With a sensored motor arrangement, both the motor and the ESC will always be in perfect sync throughout the entire rev range.

What Is A Sensorless Brushless Motor?

Sensorless ESC and motor combinations are much simpler in design and work in a similar way to the brushed motor systems supplied with most standard RC cars. Sensorless ESCs just have 3 output cables that carry the power to the motor. The motor just then responds as demanded with no feedback being sent to the ESC. These systems are generally cheaper than Sensored versions and are most suited to leisure and bashing applications. In these situations, drivers tend to use full throttle more often and cogging isn’t as much of an issue. The main benefit of these systems is that they generate more torque than a sensored system.

Which Should You Run?

It really comes down to budget and application. If you’re going to race seriously, then sensored is the only way to go in my opinion. If you’re just going to be thrashing your RC car or truck at the local park or BMX track, then a sensorless budget system will still put a smile on your face.

As always, if you have any questions or comments regarding the content covered in this article, please feel free to join in the discussion below.

 

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