Low Cogging Brushless DC Motors- Suzhou Retek Electric Technology Co., Ltd.

Low Cogging BLDC Motor Design Principle

The principle of low cogging involves minimizing the reluctance variation between the rotor magnets and the stator teeth as the motor rotates. This essential reduction is achieved through several design techniques: non-slotted stator structures (slotless design for zero cogging), skewed stator laminations (to average out the cogging peaks), and specific slot/pole count ratios (e.g., fractional slot windings) which inherently reduce ripple. The result is a substantial decrease in static torque ripple, often to less than 1% of the motor's rated torque, leading to smoother, more stable motion and a significant reduction in acoustic noise generation. This characteristic is essential for precision positioning, constant velocity control, and acoustic-sensitive applications.

Focus Area: Smooth motion profile, high positional accuracy, and minimal acoustic signature.
Key Technology: Precision magnet segmentation, skewed magnet or stator stacks, and advanced magnetic simulation to optimize geometries.
Benefit: Improves control loop stability, eliminates low-speed jitter, and enhances positional accuracy, particularly at slow speeds.
Comparison: Cogging torque is typically 10-20 times lower than in a standard, un-skewed iron-core motor.

Introduction

Detailed Parameters and Performance Data

Introduction to Smooth Motion Control Solutions

In applications where fine control, high resolution, and minimal vibration are paramount—such as in medical imaging or high-end laboratory equipment—standard iron-core motors often introduce limitations due to inherent cogging torque. This series of low cogging motors from Retek Electric Technology (RTK) is specifically designed to overcome this challenge. We leverage advanced Finite Element Analysis (FEA) modeling and precision assembly techniques to virtually eliminate static torque ripple. Our commitment as a dedicated motor manufacturer is to enable clients in sectors like medical robotics, optical systems, and high-fidelity printing to achieve uncompromising smoothness and repeatability in their motion systems, fulfilling the need for precision actuation at any speed.

Applications

Advanced Technology Highlights

Key Application Areas

Medical Diagnostics & Surgery: High-precision fluid delivery (infusion pumps), diagnostic imaging gantry positioning, and minimally invasive surgical robotics requiring smooth, backlash-free movement.
Optical & Scientific Equipment: Focusing mechanisms, mirror positioning, laser beam steering, and high-resolution microscopy stages.
Semiconductor Manufacturing: Wafer handling and precise stage positioning where any vibration could compromise process integrity.
Laboratory Automation: High-throughput sample handling systems, precision pipetting robots, and micro-dosing pumps requiring consistent, low-speed flow.
High-End Printing & Plotting: Precision paper/media feeding and printhead positioning requiring constant velocity and zero jitter.
Security and Surveillance: Silent, high-resolution Pan/Tilt/Zoom (PTZ) systems for discreet operation.

Technical Specifications

Industrial & Commercial Usage

Selected Motor Specifications

Low cogging motors are often compact but designed for high sensitivity.

Parameter	Example WC22 Coreless Series (Micro Low Cogging)	Example WO42 Outrunner Series (Skewed)
Peak Torque (Nm)	0.08 - 0.15	0.35 - 0.50
Cogging Torque (Max mNm)	<0.05 (Near Zero)	<1.5 (Low Ripple)
Rated Voltage (VDC)	12 / 24	24 / 48
Motor Diameter (mm)	22	42
Nominal Speed (RPM)	500−8,000	500−5,000
Positional Accuracy (Open Loop)	N/A (Requires Encoder)	±0.5 mechanical degrees

Additional Information

Supplementary Details & Notes

Manufacturing Process and Customization Services

Our low cogging motor production involves specialized processes to maintain geometric precision and magnetic symmetry:

Precision Skewing/Coreless Winding: Utilizing high-accuracy indexing tables and automated laser alignment to ensure the precise angle of the skew or the perfect consistency of the coreless winding structure.
High-Resolution Dynamic Balancing: Every low cogging motor is subjected to G-level dynamic balancing (e.g., G1.0) to eliminate vibration at high speeds, complementing the static smooth-motion design.
Magnetic Field Mapping: Non-contact measurement systems are used to map the magnetic field symmetry around the rotor to detect and correct any flux inconsistencies.
Integrated Sensor Options: Offering high-resolution absolute or incremental encoders, including Sin/Cos encoders, to provide feedback resolution that matches the motor's motion smoothness.
Controlled Environment Assembly: Motors intended for ultra-precision use are assembled in clean environments to prevent contamination that could introduce imbalance or noise.

Service & Support

Operational Benefits and Design Integrity

Exceptional Motion Smoothness: Near-zero cogging torque provides virtually pure rotational force, crucial for uniform speed control and indexing accuracy in high-resolution tasks.
Ultra-Low Acoustic Noise: The elimination of magnetic "locking" points results in a substantially quieter operation profile, suitable for sterile and quiet clinical or laboratory environments.
Enhanced Control Stability: Reduced disturbance torque allows control systems (servo loops) to achieve higher gains and faster, more precise settling times without instability.
Improved Accuracy at Start/Stop: Eliminates the tendency to jump past the intended position during low-speed indexing maneuvers.
High Repeatability: The smooth, predictable force curve greatly improves the precision and consistency of repeated positioning tasks.

Frequently Asked Questions

Q: How is cogging torque minimized in iron-core designs?
A: In iron-core designs, the primary method is skewing the stator stack (applying a slight rotational twist) or using specific magnet segmentation and pole-slot count combinations to ensure that the cogging forces from individual slots cancel each other out.

Q: Does low cogging automatically mean low vibration?
A: While low cogging torque (static ripple) significantly reduces vibration, overall motor vibration is also affected by dynamic rotor imbalance. Our low-cogging motors also undergo high-precision dynamic balancing to address this secondary source of vibration.

Q: Why is low cogging important for closed-loop servo systems?
A: Cogging torque acts as an unpredictable disturbance to the servo controller. By eliminating it, the controller does not need to compensate for these internal forces, allowing for tighter control, higher stiffness, and more accurate velocity tracking, especially during critical trajectory following.

Q: Can low-cogging motors handle high current loads?
A: Yes, the low-cogging design is independent of current rating. However, slotless coreless designs have lower thermal mass and require careful thermal management under high continuous load compared to skewed iron-core designs.

Resources

Component Material Selection and Impact

Key material selections supporting low cogging design:

Stator Laminations (Skewed): Utilizing thin, high-grade silicon steel laminations that are accurately stacked with a precise rotational offset (skew) to distribute the magnetic forces smoothly.
Magnetization Pattern: Precision multi-pole magnetization patterns or segmented arc magnets on the rotor ensure smooth transition points for the magnetic flux.
Bearing Selection: High-precision deep groove ball bearings (ABEC-5 or better) with specialized lubricants minimize mechanical friction and unwanted running vibration.
Winding Integrity: In slotless designs, the self-supporting coil is often reinforced with high-strength epoxy resin to maintain its critical geometric shape and air gap consistency.

About Suzhou Retek Electric Technology Co., Ltd.

Unlike other motor suppliers, Retek engineering system prevents the selling of our motors and components by catalogue as every model is customized for our customers. The customers are assured that every component they receive from Retek is designed with their exact specifications in mind. Our total solutions are a combination of our innovation and a close working partnership with our customers and suppliers.

As China Low Cogging Brushless DC Motors Manufacturers and Wholesale Low Cogging Brushless DC Motors OEM/ODM Suppliers, Retek business consists of three platforms: Motors, Die-Casting and CNC manufacturing and wire harness. Retek products are widely supplied for residential fans, vents, boats, airplanes, medical facilities, laboratory facilities, trucks and other automotive machines.

Welcome to send us an RFQ, it is believed you will get the best cost-effective products and services here!

Customized Solutions

Quality Assurance

Global Export

Suzhou Retek Electric Technology Co., Ltd.

Recommended LINS

Brushless DC Linear Motor Ironless Low Cogging Low Voltage Brushless DC Motors (24VDC) Brushless DC Motor with Integrated Controller Brushless DC Linear Motor Iron Core High Force Brushless DC Fan Motor for High CFM Cooling High Torque Brushless DC Motors Compact DC Brushless Motors High Power Brushless DC Motors

Message Feedback

Low Cogging BLDC Motor Design Principle

Related Products

Dual voltage 230VAC/12VDC into one drive for remote area solar panel power supply system W70 Series with metal shell

Brushless DC Motor for Digital Tools 36mm Diameter W36 Series

BL57 57mm Diameter Brushless DC Motor

Permanent Magnet Dc Shunt Brush Motor 78mm Diameter with Slot Type Commutator

Non-permanent-magnet DC Brushed Motor 80mm Diameter for Industrial Pump with slot Type Commutator

Efficient Precise Planetary Motor With Gear Head 28mm Diameter Brushless Motor