In fields such as industrial automation, UAVs, robotics, and air-conditioning compressors, Sensored BLDC motors are widely used for their high precision, fast response, and smooth operation. However, during the selection process, many engineers and buyers often make mistakes due to incomplete understanding of specifications or insufficient analysis of application scenarios. These errors can lead to poor system performance or even unnecessary cost increases. This article outlines the most common mistakes when selecting sensored BLDC motors and provides practical strategies to avoid them.
Ignoring the Difference Between Sensored and Sensorless Motors
Many users focus only on power and speed ratings while overlooking whether the motor includes Hall sensors. Sensored motors use Hall feedback for accurate commutation, making them ideal for low-speed startup, frequent stop/start, or precise control applications. In contrast, sensorless motors are better suited for high-speed or cost-sensitive systems.
Mistake: Using a sensorless motor in a low-speed control system, causing startup issues or unstable rotation.
Solution: Determine the control requirements first. If your system demands precise positioning or smooth low-speed control, a sensored BLDC motor is the right choice.
Focusing Only on Rated Power While Ignoring Torque and Efficiency Curves
Many people look only at “rated power (W)” without considering the torque-speed curve, which reflects the true performance of a motor. Motors with the same power rating can have vastly different torque outputs and efficiency ranges.
Mistake: Selecting a motor with insufficient torque despite matching power ratings.
Solution: Analyze the load profile and verify the motor’s maximum torque, continuous torque, and efficiency curve to ensure it operates in its optimal range.
Using an Incompatible Driver or Controller
Sensored BLDC motors require drivers that can process Hall sensor feedback. Using a generic, sensorless driver often leads to commutation errors or unstable operation.
Mistake: Connecting a sensored motor to a driver that doesn’t support Hall inputs.
Solution: Confirm that the driver supports “Hall sensor input” and check the wiring sequence and signal compatibility according to the manufacturer’s diagram.
Underestimating the Importance of Heat Dissipation and Environment
During long-term high-load operation, sensored motors can experience temperature rise, which may cause Hall sensor drift or damage if heat management is neglected.
Mistake: Using a fully enclosed motor in a high-temperature environment, resulting in reduced efficiency or failure.
Solution: Choose motors with heat sinks or forced-air cooling, and for humid or dusty conditions, select models with higher protection ratings (IP54 or above).
Ignoring Inertia Matching and Acceleration Performance
In systems requiring fast dynamic response—such as robotic joints or CNC spindles—inertia matching between the motor and the load is crucial.
Mistake: Selecting a motor with low rotor inertia, leading to vibration or control instability.
Solution: Calculate the ratio between load inertia and motor inertia (typically kept below 3:1) to ensure quick yet stable response.
Overlooking Manufacturer Credibility and Data Accuracy
Some buyers rely solely on online specifications without verifying actual test data or lifespan reports from the manufacturer. This can result in motors that underperform or wear out prematurely.
Mistake: Choosing based only on advertised ratings or market reputation.
Solution: Prefer manufacturers with ISO certification and detailed performance test reports under rated voltage, load, and temperature conditions.
Conclusion: Scientific Selection Ensures Long-Term Stability
To summarize, the most common mistakes in sensored BLDC motor selection stem from misunderstandings of electrical parameters, poor system matching, and environmental neglect. A scientific selection process should include: requirement analysis → parameter verification → driver compatibility → on-site testing. By comprehensively evaluating electrical, mechanical, and environmental factors, users can ensure the motor operates efficiently, reliably, and cost-effectively—laying a solid foundation for stable performance and long-term energy savings.