Drone motors are built for different jobs. An FPV racing drone needs rapid acceleration and high RPM, while a heavy-lift drone must maintain thrust under substantial loads. Both may use brushless DC (BLDC) motors, but their operating conditions place different demands on the stator core.

Non-grain-oriented electrical steel (NGOES) is commonly used in laminated motor stators. Its magnetic properties and core-loss performance influence how the motor behaves under different operating conditions.

Key Takeaways

Drone motor requirements vary with operating speed, load, and duty cycle.
Electrical frequency depends on motor RPM and rotor pole count, not RPM alone.
Core-loss performance, magnetic loading, and lamination thickness should be evaluated against the intended motor design.

How Electrical Steel Affects Drone BLDC Motors

Most conventional drone propulsion motors have permanent magnets on the rotor and copper windings around a laminated stator core.

As the motor operates, changing magnetic fields produce hysteresis and eddy-current losses in the stator. These losses contribute to heating, particularly as electrical frequency increases.

The relevant frequency, however, is not determined by mechanical speed alone.

Why Motor RPM Alone Is Not Enough

Two drone motors running at the same RPM can operate at different electrical frequencies because they have different rotor pole counts.

The fundamental electrical frequency of a permanent-magnet BLDC motor can be calculated as:

Electrical Frequency (Hz) = RPM × Number of Pole Pairs / 60

Consider a hypothetical operating speed of 30,000 RPM:

Rotor Pole Count	Pole Pairs	Electrical Frequency
2 poles	1	500 Hz
4 poles	2	1,000 Hz
14 poles	7	3,500 Hz

Higher pole counts produce higher fundamental electrical frequencies at the same RPM, making electrical steel core loss an important consideration when comparing stator materials.

1792549991230-Electrical Frequency in Drone BLDC Motors.webp

Drone BLDC motor electrical frequency formula and comparison of 2, 4, and 14 rotor poles at 30,000 RPM

Electrical Steel Requirements for Different Drone Applications

Many drones use similar motor structures, particularly outer-rotor BLDC designs. Their operating speed, load, and duty cycle can nevertheless differ substantially.

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Comparison of electrical steel requirements for FPV racing, cinematic, agricultural, and heavy-lift drones

FPV Racing Drones: High-Speed Operation

FPV racing drones rely on compact, relatively high-Kv outrunner motors for rapid acceleration and high-speed flight.

The T-MOTOR P2207 V3 series, for example, includes 12-slot, 14-pole configurations with different Kv options.

With seven rotor pole pairs, electrical frequency rises quickly as RPM increases. This makes high-frequency core-loss performance particularly relevant to stator material selection.

Thin-gauge NGOES, including 0.20 mm and 0.10 mm options, may be considered for these applications. However, lamination thickness should be evaluated alongside measured core-loss performance.

Cinematic and Long-Endurance Drones: Sustained Efficiency

Cinematic drones spend considerable time hovering or making controlled movements. Long-endurance UAVs, including survey and monitoring aircraft, may operate for extended periods near a preferred cruising speed.

For these motors, core-loss data at commonly used operating frequencies is more useful than comparing materials only at the highest possible frequency. A low-loss grade can be attractive, but its benefit depends on where the motor operates during a typical flight.

Agricultural Drones: Changing Payloads

Agricultural spraying drones commonly use large propellers driven by relatively low-Kv motors.

A spraying drone may begin its mission carrying a substantial liquid payload. As the liquid is discharged, the required thrust changes, along with the load placed on the propulsion system.

Electrical steel with suitable saturation characteristics helps accommodate the required magnetic flux. Low core loss also helps limit stator heating during sustained operation.

For manufacturers producing large numbers of these motors, consistent magnetic properties and sheet dimensions are important for repeatable stator production.

Heavy-Lift and Industrial Drones: High Magnetic Loading

Heavy-lift drones often use larger, high-torque motors to drive propellers capable of producing substantial thrust.

In these designs, the stator may experience high magnetic loading. Operating too close to magnetic saturation can limit the available design margin and affect the relationship between current and torque.

High-grade NGOES is a common material option for laminated motor stators. Core-loss and magnetic induction characteristics need to be considered alongside the motor's intended operating load.

VTOL Drones: Lift and Cruise Motors

Some vertical take-off and landing (VTOL) drones use separate propulsion systems for vertical lift and forward flight.

Lift motors operate during take-off, hovering, and landing, while cruise motors may spend much of their time near a more consistent operating point.

Their electrical steel requirements can differ, particularly in core-loss performance at the relevant operating frequencies.

Manufacturing Considerations for Compact Drone Stators

Compact drone stators often have narrow teeth, making cutting quality especially important. Cutting-induced stress can affect the magnetic properties of the steel, particularly near the tooth edges.

Burrs and damaged insulation between laminations can increase losses in the finished core. Even when low-loss NGOES is used, poor cutting quality can reduce its performance advantage.

What Drone Motor Manufacturers Should Specify When Buying Electrical Steel

When sourcing NGOES coils, motor manufacturers can use operating data and material requirements to identify suitable electrical steel grades.

Information to Provide	Why It Matters
Motor type and drone application	Identifies the intended operating conditions
RPM range and rotor pole count	Establishes the fundamental electrical frequency range
Magnetic flux density and core-loss requirements	Defines relevant magnetic performance targets
Lamination thickness and coating	Supports compatibility with downstream processing
Coil dimensions and tolerances	Helps with production planning and material utilization

HWHG non-grain-oriented electrical steel coils for downstream drone BLDC motor stator manufacturing

HWHG supplies non-grain-oriented electrical steel coils for downstream motor-core manufacturing. Buyers can inquire about available grades, coil specifications, and relevant material test data.

Conclusion

For drone motor manufacturers sourcing NGOES coils, operating speed, pole count, and expected magnetic loading provide a practical starting point for discussing suitable electrical steel grades with suppliers.

How Drone BLDC Motor Manufacturers Select Electrical Steel for Different Operating Conditions

Hysteresis Loss in Electrical Steel: What Changes It and Why It Matters

50,000 RPM EV Motors: What Ultra-High-Speed Designs Mean for Electrical Steel

Electrical Steel Core Loss vs. Frequency: What the Test Data Really Means

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