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Sensor based motors are most often used in applications where the starting torque varies greatly or where a high initial torque is required, such as in a RC car. If one looks at the industrial or aerospace applications of brushless motors, one would be hard pressed to find sensorless motors being used due to lack of starting torque and unreliable operation under noisy electrical conditions. Sensored brushless ESC motor systems always know the position of the rotor. This is especially critical at low speed as well as at the start condition when there is no rotor movement. With the proper rotor position information, the ESC can apply power to the correct rotor phase combination.
Novak ESC’s, such as the GTB, can apply 100% power to the correct phase set immediately after decoding the signal from the receiver while the rotor is stationary.
This allows the sensor based brushless motor to act more like a brushed motor and deliver maximum torque at zero speed without the loss associated with brushes and the commutator. Another benefit
of sensored design is that the motor and ESC are always in sync with each other at all speeds.
The time required to attain the rotor position from the Hall Effect sensor is on the order of a few micro seconds. If a given motor is turning at 80,000 RPMs that equals 1,333 revolutions per second or 1.33mS per revolution. That is a very long time in terms of a microcontroller running at 20MHz (equates to 26,600 clock cycles @50 nanoseconds per cycle). The microcontroller is capable of executing many instructions in that time frame.
In contrast, a sensorless ESC does not know the position of the rotor until it is spinning at a certain speed; one cannot simply apply power to the coils and 
expect the motor to start up properly. A start up phase sequence is required to get the motor running.
Most sensorless ESC's use a ramp-up method in which power is applied to two phase coils to get the rotor into a known position within the created stator flux (like a stepper motor). The motor phases are then energized according to a certain coil energizing pattern and the motor speed is gradually increased by slowly decreasing the commutation period. During this ramp up period, the phase that is not being used is monitored for back-EMF. Once the speed is high enough to produce detectable back-EMF, the algorithm switches over from the ramp-up method to the back-EMF or zero crossing feedback mode, as the back-emf is small compared to the battery.
So the myth that the sensor based ESC is slower then the sensorless ESC is completely BUSTED; as a matter of fact the sensorless ESC's have to spend a fair amount of time filtering and making decision on back-emf detection while the Sensor based feedback system is much faster, more reliable, and overall far superior.
As far as the power output or top RPM of a given size motor is concerned, it does not matter what type of sensing is used. These motor performance parameters are based on factors such as the size of the rotor, the stator design, the air gap between the stator and rotor, etc., and not on the type of sensing being used.
At Novak we design and build our motors in-house, using computer based motor design software. We purpose-design and build the brushless motors from the ground up specifically for RC car applications. Through tracking and testing based feedback provided by Novak 
employees, and with the help of several world class RC drivers who test and verify design parameters, we are able to continually improve the design as well as develop new materials used to build brushless motors. This constant cycle of testing,verifying, and feedback provides the best possible solution for building and improving motors for RC cars, unlike other brushless suppliers who purchase low cost Chinese made sensorless motors as they do not have the in-house capability to design or build brushless motors themselves.
The cost of additional sensors and wires is minimal compared to tremendous benefits they provide. Over the last five years of brushless motor production we have had very minimal issues with the sensor wires and connectors.
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