How to Select Motors for FPV Drones
Posted by Jenny.
from the Hobbies category at
04 Jan 2024 01:39:52 am.
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Brushless Motors vs. Brushed Motors
In the wide array of RC motors, two primary types emerge: brushless and brushed. Brushless motors, favored for their robustness and power, take the spotlight in the FPV drone arena. This guide will exclusively focus on brushless motors, setting aside brushed motors, commonly found in toy drones due to their economical nature.<o:p></o:p>
Estimating Drone Weight and Frame Size
When evaluating the total weight of your FPV drone, consider all components: frame, FC, ESC, motors, propellers, RX, VTX, antenna, LiPo battery, GoPro, and more. While pinpoint accuracy isn't mandatory, a close estimation proves crucial. It's preferable to slightly overestimate the weight, ensuring an ample power reserve, than to underestimate and grapple with takeoff challenges.
Determining Thrust Requirements
Compute the minimum thrust required for your motor and propeller pairing based on your estimated drone weight. A general guideline is to ensure that the combined thrust from all motors is at least double the weight of the quadcopter. For example, a 1kg drone should generate a total thrust of at least 2kg. Racing drones might aim for a notably higher thrust-to-weight ratio, such as 10:1 or 14:1, offering exceptional agility but demanding adept piloting skills.
Connecting a Brushless Motor
To set a brushless motor into motion, an ESC (electronic speed controller) is indispensable. Unlike brushed motors with only two wires, brushless motors boast three. These wires can be connected to the ESC in any order, and to reverse rotation, a simple swap of any two wires suffices. Alternatively, reversing motor direction can be achieved through software settings.
Motor Size Explained
Brushless motor size is typically denoted by a four-digit code (AABB), representing stator width (AA) and height (BB) in millimeters. The stator, the stationary section housing copper windings, plays a pivotal role in influencing torque. Increasing stator dimensions enhances torque, enabling a faster spin of the propeller and increased thrust, albeit with the trade-off of added weight and reduced responsiveness.
Key Components of a Motor
Motor Stator:
The immobile segment containing coils that generate a magnetic field for rotation.
Magnets：
Permanent magnets on the rotor, creating a stable magnetic field.
Motor Bell:
The protective casing safeguarding magnets and windings, often designed for improved cooling.
Motor Shaft:
Transfers torque from the motor to the propeller.
Striking a balance in stator dimensions is paramount; a larger stator amplifies torque but introduces additional weight. Achieving the right equilibrium is critical for optimizing performance based on your drone's specific application.
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