Why do FPV Quadcopter Motors (usually the more expensive ones) draw lower amps than regular motors?
And why are they more squat(disk shaped) as opposed to normal motors which are about the same diameter and height?
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1 Answer
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While doing FPV using multirotor, endurance is essential as you want to stay in air for maximum time in limited battery capacity. This requires minimizing current consumption while designing a multirotor. Multirotors use flight control system which works best with relatively lower rpm motors as response is faster with low rpm motor. This demands usage of bigger diameter propeller for desired thrust which expects high torque motor to drive it. Now we expect higher torque at lower current consumption for our purpose.
In case of brushless DC motor, torque depends on number of poles and current consumption depends on coil. Now in order to increase torque one has to increase number of poles and consequently diameter of motor is increased. In order to decrease coil, we have to decease length of stator. These requirement of large radius and small stator length results in disc like shape for a high torque and low current consuming motor.
