First of all, the choice of model aircraft brushless motor is generally not considered shell material, mainly consider the following parameters:
a, size
everybody choose brushless motor, will see a lot of naming a similar model, such as 2212, 2204, etc. , top two stator outer diameter (mm）And after two stator height (mm）。 The diameter and height of the stator, the stator iron core, the greater the coil winding is, the more the number of turns, show is the greater the power of the motor. Size and the power of the motor, the greater the weight.
as a motor is 2212, says the 22 mm outer diameter of the stator, the stator height is 12 mm. Outer diameter of the stator and stator height and motor power is proportional to the, 2216 more than 2212 motor stator height is high, the power must be also big. The significance of this size is that the model can compare two motor power size, but the same is compared commonly stator diameter and height is not the same, or different height and diameter, the stator outer diameter and height are not the same as it is difficult to through this model.
it's important to note that the size is to specify the son, not motor installation dimensions, the thickness of the motor casing, thermal bad shape, height of the base and so on all affect motor appearance size, so do with the stator size power of judgment standard and by spectrum than with envelop dimensions.
2, the number of motor slot number and
slot number (N): the number of slot stator core. Brushless motor is the three-phase motor, so the slot number is a multiple of 3. The number of (P): on the stator magnetic steel, the number of magnets must be used in pairs, north and south poles number must be even.
motor slot number and the number of some models to write directly to the number of slot number N P, such as 12 p14n, is 14 groove 12 very mean.
slot number and the number of features:
slot number (N)And the number of (P)Is inversely proportional to the highest speed, model aircraft brushless motor, dongguan is the slot number (The number of)The smaller, the higher the best speed of the motor. Such as 9 n12p maximum speed is higher than 12 n14p. In the slot number (N)The same situation, the number of (P)Is proportional to the torque, the number is larger, the greater the torque. Under normal circumstances, the slot number (N)And the number of (P)The smaller the sense of frustration, the greater the motor (At the time of motor is not charged, rotating motor with the hand, will feel a card a card sense of frustration), theory of motor vibration will be less, but due to the slot number after much more difficult to do dynamic balance. Three, KV value
brushless motors KV value defined as RPM/V, the meaning of the input voltage increase 1 V (V)Idle speed, brushless motor (Revolutions per minute)The speed of the increase value. From the point of this definition, voltage and motor idling speed is a strict linear proportional relationship, and is a constant, regardless of the motor in the working voltage, the relationship between voltage and rotating speed are subject to value.
1, the calculation of idle speed
this value refers to the motor idling speed and without such as propeller load voltage, the relationship between KV is 1000, for example, in the 11th. 1 v voltage under the idling speed is 11. 1×1000 = 11100 RPM.
2, relatively high and low KV value (Only the same outer diameter of the stator and stator height of the same model, their KV value is more meaning)
3, should not be compared by KV motor is good or bad, the dongguan plant protection unmanned aerial vehicle (uav) motor, cannot say is better than KV600 KV380, the same type of different KV value of motor is the same price.
4, outer rotor and rotor
brushless motor, according to the position of the stator can be divided into rotor and rotor two.
outer rotor, stator, rotor is called outer rotor outside.
the rotor outer bread with the stator, rotor and shell together, rotation, the shell (Not including the base)With output shaft rotation. Rotor torque is large, low KV value.
in the stator, rotor, outside rotor inside the inner rotor
with exterior rotor on the contrary, inner rotor brushless motor is wrapped in stator rotor, rotor rotation, just turned (Shell did not turn)。 Inside the rotor torque is small, high KV value.
