PCB Stators for Axial Flux and High-Speed Motors

Tony Zh Yi

·September 27, 2026

·11 min read

PCB Stators for Axial Flux and High-Speed Motors

A PCB stator uses conductive traces on a printed circuit board instead of traditional copper wire windings. This design allows for thinner, lighter axial flux and high-speed motors. Infinitum Electric's PCB stator technology cuts weight by up to 50% compared to laminated stators by using less metal. However, these motors have trade-offs in current handling and mechanical strength. Engineers often ask if PCB stators are a real alternative to laminated stators. This article gives a practical comparison of both designs. Readers will learn how PCB stators work in real applications and where they fit best. The answer depends on specific motor needs and operating conditions.

Key Takeaways

PCB stators use flat traces on circuit boards instead of copper wire windings to cut motor weight by up to 50%.
These stators work best in high-speed, medium-current uses like drones, eVTOL, and reaction wheels.
PCB stators can't handle as much current as laminated designs. But they give you higher efficiency and move heat away better.
Engineers change the number of layers and the width of traces. This helps them balance voltage, current, and heat limits for their motor.

How PCB Stators Work

A multilayer printed circuit board forms the foundation of a PCB stator. Flat copper traces on the board replace the wound copper wire found in conventional motors. This approach changes how engineers design the electromagnetic circuit. The board material also serves as mechanical support and insulation between conductors.

Copper Traces Replacing Windings

The manufacturing process creates copper traces through photolithography and etching. These traces form complete coil patterns on each board layer. Vias connect the layers electrically to create a three-dimensional winding structure. This method produces a pcb distributed winding that distributes conductors evenly across the stator area. Each layer contributes to the overall coil turns. The designer controls the number of turns by adjusting the trace pattern and layer count. A typical design uses multiple layers depending on the voltage and current requirements.

The copper fill factor in a PCB stator exceeds that of wire-wound designs. Rectangular traces pack more efficiently than round wire. The fill factor can be significantly higher in well-designed boards. More copper in the same space reduces resistive losses significantly. The flat shape also improves heat transfer from the conductor to the board material. Thermal management becomes simpler because heat spreads through the board layers efficiently. This characteristic helps maintain performance under continuous operation.

PCB windings offer advantages over traditional windings. The etching process produces exact geometries with high repeatability. Every stator in a production run matches the design specification. This consistency improves motor performance and reduces variation between units. The absence of slot insulation further improves efficiency. Traditional windings require insulation between the wire and the core. PCB stators eliminate this layer. The copper sits directly on the board substrate with precise spacing. This construction also reduces the effective air gap between stator and rotor. Shorter air gaps improve magnetic coupling and increase torque density.

Magnetic Circuit and Core Options

The magnetic circuit in pcb stator motors must close through the rotor and any core material. Magnetic flux travels from permanent magnets across the air gap and into the stator structure. The magnetic flux density in this gap directly affects torque production. Designers calculate this value based on magnet grade and geometry. A higher flux density produces more torque but requires careful thermal management.

Some designs include a soft magnetic composite back iron behind the PCB. This material provides a low-reluctance path for magnetic flux. The composite handles high-frequency operation without significant eddy current losses. The air-gap flux distribution becomes more sinusoidal with a properly designed core. This shape reduces cogging torque and improves smooth rotation. The back iron also adds mechanical stiffness to the stator assembly.

Other designs use air-core pcb stator technology. These motors remove all ferromagnetic materials from the stator. Air-core axial flux motors operate without hysteresis or eddy current losses. The electrical time constant drops to extremely low values. This characteristic makes them ideal for high-speed operation. The absence of iron also eliminates saturation effects entirely. The motor can handle current spikes without performance degradation.

An air-core pcb stator contains only copper traces and dielectric material. The rotor magnets provide all the magnetic field energy. This configuration delivers high specific peak torque. The motor responds quickly to control signals without magnetic saturation. Applications requiring rapid acceleration benefit from this design approach.

Printed circuit board (pcb)-based winding technology continues to evolve. Fabricators now offer thicker copper layers for higher current capacity. Advanced substrates handle elevated temperatures without degradation. These improvements expand the application range for pcb stators. The technology now supports designs that were impractical just a few years ago.

The choice between air-core and core-backed designs depends on the application. Engineers must balance torque requirements against speed constraints. The right combination of traces, layers, and core materials produces an efficient motor. Understanding these trade-offs helps designers select the best configuration.

Inside the PCB Axial Flux Permanent Magnet Motor

A pcb axial flux permanent magnet motor puts its magnets and stator in a flat, pancake shape. The magnetic flux moves parallel to the shaft in this design. This axial path allows a large diameter with a very short stack length. The result is a compact motor with high torque density. A pcb-based afpm motor can be much lighter than a normal radial-flux motor of similar power. This weight drop comes from swapping steel laminations and copper wire for a thin circuit board.

Why Axial Flux Needs Low Eddy Losses

High-frequency operation makes eddy current losses a main concern in axial flux motors. These motors often run at high electrical frequencies to reach high power density. The changing magnetic flux causes circulating currents in any conductive material near the air gap. These eddy currents make heat and waste energy. An axial-flux permanent-magnet motor with a solid core has severe losses at these frequencies. The pcb axial flux permanent magnet motor cuts this problem by using thin copper traces and optional composite cores. The magnetic flux density in the air gap still drives torque production. However, the low-loss materials keep the eddy currents small. This efficiency matters for an axial flux permanent magnet synchronous motor that must run nonstop at high speed.

Thermal and Space Constraints in Thin Profiles

A thin axial flux motor has very little room for cooling. Heat must move through the board and any back iron to reach the surface. The flat shape helps because heat spreads sideways through the copper. Still, the compact profile limits the total thermal mass. Designers must watch current density closely to avoid overheating. A two-stator, one-rotor axial-flux internal rotor setup increases torque for a given diameter. It also adds more heat sources. The windings in each stator must share the thermal load. An axial flux motor for a drone or eVTOL application faces tight weight limits. Every gram of cooling hardware cuts payload. The PCB stator helps here because it removes bulky slot liners and end turns. The magnetic flux path stays short, so less material is needed. This keeps the motor light and efficient.

High Torque Density in PCB Axial Flux Motors

Permanent Magnet Motor Architecture

A high torque density pcb axial flux permanent magnet motor gets its edge from short magnetic paths. The magnetic flux moves a short way between the rotor magnets and the stator traces. This short path lowers magnetic reluctance and raises the magnetic flux density in the air gap. More flux density means more force on the rotor using the same magnet material. The design also gains from low copper losses. Flat traces pack tightly and carry current with less resistance than round wire. Less resistance means less heat and better efficiency. Together, these two factors create a high torque density pcb-based afpm motor that beats many common designs.

A prototype axial flux PCB stator motor shows this performance. The prototype gives strong torque in a package that weighs much less than a laminated equal. Engineers can look at this data point when sizing their own designs.

Comparing With the Axial-Flux Permanent-Magnet Motor Baseline

A traditional axial-flux permanent-magnet motor with a laminated core gives high torque density at low speeds. The laminated steel carries magnetic flux well and handles high current. But eddy currents in the steel cause losses at high frequency. A pcb-based afpm motor avoids this problem. Thin copper traces and optional composite cores keep eddy losses low. The PCB design also removes slot liners and end turns. This simpler build cuts weight and size. For high-speed, low-power uses, the PCB stator wins on efficiency and compactness. The laminated-core design still handles higher current. Engineers must weigh these trade-offs for each application. A high torque-density pcb-based afpm motor fits drones, spindles, and other high-speed uses. The axial flux motor with a PCB stator gives strong performance where weight and frequency losses matter most.

Advantages and Limitations of PCB Stators

Weight, Cost, and Efficiency Gains

Losing weight is the most obvious plus of pcb stators. Infinitum Electric's design cuts weight by up to 50% compared to laminated stators. A pcb axial flux permanent magnet motor can be much lighter than a normal radial-flux motor of similar power. This drop comes from removing steel laminations and bulky copper wire. The thin circuit board takes the place of both the iron core and the slot insulation. Less material means lower shipping costs and easier handling during assembly.

Cost savings follow the same path. The etching process makes exact trace shapes in one step. Manufacturers skip the winding, slot lining, and lamination stacking steps that traditional motors need. High pole counts become easy because the designer adds traces to the board layout instead of winding more coils. This simplicity shortens production time and cuts labor costs.

Efficiency gains come from several sources. The copper fill factor in a PCB stator is high because rectangular traces pack tightly. More copper in the same space lowers resistance and cuts copper losses. Heat spreads sideways through the flat board layers, so thermal dissipation works well even in a thin profile. The compact shape also shortens the magnetic flux path. A shorter path raises flux density in the air gap and makes more torque per unit of magnet material. These factors work together to deliver high torque density in a small package.

Current Handling and Mechanical Limits

Current handling is still the main limitation. Thin copper traces carry far less current than thick wire windings. A pcb stator motor that needs high continuous current must use more layers or thicker copper. Both options add cost and complexity. Engineers must watch current density closely to keep the board substrate from overheating.

Mechanical strength also limits the design. A bare circuit board flexes under magnetic forces. The stator needs a backing structure or a composite core to stay rigid. Without that support, vibration and noise increase at high speed. The board material itself melts at a lower point than steel laminations. This constraint caps the maximum operating temperature.

Insulation challenges add another layer of difficulty. The dielectric material between copper layers must handle the voltage difference across windings. A pcb windings design with many layers puts electric stress in a small space. Designers must space traces carefully and pick substrates rated for the application voltage. An air-core pcb stator removes the core but still depends on the board for insulation. Any breakdown between layers causes a short circuit and motor failure.

These trade-offs do not rule out pcb stator technology. They simply define where it fits best. Applications with moderate current and high speed benefit most. Engineers who need extreme current capacity should still think about laminated designs. The right choice depends on the balance between weight, efficiency, and raw power.

Design Tips and Where PCB Stator Motors Are Used

Trace, Layer, and Via Design

Engineers should begin with the shape of the traces. Wider traces carry more current and have lower resistance. When traces fit tightly on each layer, the copper fill factor goes up. A higher fill factor cuts losses and makes the motor more efficient. Designers must find a balance between trace width and the space needed for insulation between conductors.

The number of layers changes how much voltage and current the motor can handle. More layers mean more turns and higher voltage. Most designs use multiple layers. Vias link these layers into one complete circuit. Where you place vias is important because bad placement creates hot spots. Designers should spread vias out evenly to share current and heat. Thermal management also needs close attention. Thick copper helps move heat across the board. A backing plate or composite core adds stiffness and gives magnetic flux a path to follow. Engineers who add a core must line it up carefully with the pcb windings to prevent eddy losses.

eVTOL, EVs, and Reaction Wheels

Companies like Infinitum Electric now bring PCB stator technology to EV motors. The light design works well for electric vehicles because every kilogram saved adds range. An axial flux permanent magnet motor with a PCB stator also suits eVTOL aircraft and drones. These platforms need high torque density in a thin package. High-speed spindles, servo motors, and fans get the same benefits.

Reaction wheel systems for spacecraft depend on precise, efficient motors. A high-performance reaction wheel systems design uses PCB stators to cut mass and speed up response time. Satellite attitude control systems need this kind of reliability. Robotic actuators also benefit from compact, lightweight motors. Robotic actuators in humanoid or collaborative robots need high torque in small joints. An axial flux motor with a PCB stator provides that performance.

Custom electric motor design platforms for OEMs focus on PCB stator axial flux motors. These platforms build prototypes in weeks. The finished motors run lighter, quieter, and more efficient than laminated options. Engineers who need a fast path from idea to hardware should think about this route.

PCB stators give up some raw current capacity to gain compact size, better heat performance, and simpler manufacturing. This trade works well for an axial flux motor and other high-speed uses where size, weight, and frequency losses matter most. Engineers get much lower weight and better efficiency, but they lose some peak current handling. Torque density stays competitive in moderate-current designs. New trends include thicker copper layers, better substrates, air-core designs, and hybrid core integration. These improvements keep expanding where the technology can be used. Engineers comparing laminated options should focus on uses with moderate current needs and high-speed operation. The right choice depends on the specific balance of power, weight, and thermal limits.

FAQ

Which applications suit PCB stators best?

PCB stators help axial-flux motors in eVTOL and drone platforms. Reaction wheel systems and robotic actuators also benefit from the light and small design. These uses need high speed with moderate current.

How does current handling compare with wire-wound designs?

A PCB stator handles less current than thick copper wire windings. Adding more layers or using thicker copper boosts capacity. Very high current needs still work better with standard laminated stator designs.

What thermal limits apply to PCB stators?

An axial flux motor with a PCB stator stays cool because flat traces spread heat well. The board material softens at a lower temperature than steel laminations. Copper layers help move heat, but designers must check current density.

Can engineers scale a PCB stator for higher power?

Yes, adding layers or thicker copper increases output. A prototype shows the practical power level. For very high current, laminated stators still work better. The choice depends on the specific power and weight goals.