1. Core Parameters (Key for Selection)
KV Rating KV Value
Definition: The rotational speed of the motor per minute for each 1V increase in voltage under no-load conditions. The calculation formula is "Rotational Speed = KV Rating × Voltage" (under no-load conditions).
Application Value: Higher KV ratings mean faster motor speed and lower torque, suitable for high-speed flight with small propellers (e.g., FPV drones). Lower KV ratings mean higher torque, suitable for heavy-load flight with large propellers (e.g., aerial photography, agricultural drones).
Stator Size Motor Specification
Definition: The core specification identifier of drone motor stators, expressed as a 4-digit number (e.g., 1408, 2207, 2814). The first two digits represent the stator diameter (unit: mm), and the last two digits represent the stator height (unit: mm).
Application Value: Larger stator size means stronger motor power output and torque, which is a key identifier for quickly distinguishing motor specifications and matching the overall weight of the drone.
2. Components (Core of Craft and Material)
Stator Fixed Component
Definition: The fixed component of the motor, made of high-purity silicon steel sheets laminated together, with enameled wire tightly wound on the surface. It is the core component that generates an alternating magnetic field to drive the rotor to rotate.
Application Value: Higher purity of silicon steel sheets and better lamination accuracy result in lower motor energy loss, higher efficiency, and more controllable heating.
3. Performance Metrics (Core Competitiveness)
Efficiency Energy Conversion
Definition: The ratio of the mechanical power output by the motor to the electrical power input (usually expressed as a percentage), reflecting the degree of energy loss when the motor converts electrical energy into mechanical energy.
Application Value: Higher efficiency means lower motor energy loss, less heating, and longer drone flight time, which is one of the core selling points of high-end drone motors.
4. Motor Types (Match Application Scenarios Quickly)
Brushless Motor Mainstream Type
Definition: A type of motor without brushes and commutators, which realizes commutation control through an Electronic Speed Controller (ESC). It is divided into two categories: inner rotor brushless motors and outer rotor brushless motors.
Application Value: No brush wear, high efficiency, long service life, and low noise, which is the mainstream choice for professional drones. Inner rotors are suitable for high-speed flight (FPV drones), and outer rotors are suitable for high-torque heavy loads (aerial photography drones).
5. Matching Parts (Key for Normal Motor Operation)
Electronic Speed Controller (ESC) Control Component
Definition: The core component connecting the flight controller, battery and motor, responsible for receiving flight controller instructions, adjusting the current and voltage output to the motor, and controlling the motor speed and steering. Most drone-specific ESCs are brushless.
Application Value: 1. Matching Points: ESC continuous current ≥ 1.2 times the motor's rated current (to avoid overload burnout), and the voltage specification is consistent with the motor/battery. 2. Core Protocol: ESCs supporting DSHOT protocol (such as DSHOT600) have faster response, suitable for FPV drones.
6. Selection Skills (Practical Guidance for Landing)
Weight & Power Matching Primary Selection Basis
Definition: The core corresponding relationship between the overall weight of the drone (including battery and load) and the total motor power, which is the primary basis for selection.
Application Value: 1. Reference Formula: Single motor power ≥ total drone weight (kg) × 100W (basic flight time). For violent flight/heavy load, single motor power ≥ total drone weight (kg) × 150-200W.
7. Maintenance & Service Life Extension (Reduce Use Cost)
Daily Cleaning & Inspection Prevent Potential Failures
Definition: Basic inspection and cleaning of the motor before and after drone flight, which is a key step to find potential failures and extend service life.
Application Value: 1. Cleaning Points: Use a soft brush to clean dust and debris in the motor shell and the gap between the stator and rotor. After marine flight, rinse with clean water (dry before use) to avoid salt spray corrosion.
8. Common Misconceptions (Correct Cognitive Deviations)
Misconception 1: Higher KV = Stronger Motor Power Wrong Cognition
Wrong Cognition: It is believed that KV rating is the core indicator for measuring motor power, and the higher the KV rating, the stronger the drone's flight power.
Correct Interpretation: KV rating only reflects the motor's "sensitivity of speed to voltage", not the power strength. The core of motor power depends on "torque" and "power".