Stator winding machines span a range from simple manual coil formers to highspeed automated winders. 

Types of stator winding machines include basic handoperated or semi-automatic rigs, as well as fully 

automated systems. Manual and semi-automatic machines typically feature a single winding head; operators 

form coils on the machine and insert them by hand. By contrast, fully automatic stator winding machines 

integrate multiple servo-driven axes to wind, cut, and even insert coils into stator slots without human intervention. 

Key categories include:

1. Manual/Semi-Automatic Machines: Entry-level winding tables or single-head machines that require human 

loading of the stator and transfer of finished coils. They are simple and low-cost but rely on operator skill 

and have lower throughput.

2. Fully Automatic Machines: Multi-axis, servo-controlled systems that perform entire winding cycles automatically. 

These machines handle wire feeding, tension control, coil forming, and often incorporate auto-insertion of coils 

into the stator. They offer high repeatability and speed for large-volume production.

3. Specialized Configurations: Some machines are tailored to specific winding styles (e.g. multi-strand windings, 

flat-wire or hairpin coils) to maximize slot fill or suit unique stator designs. These may use special tooling or 

multiple winding heads to achieve complex coil arrangements.

4. Each type of winding machine serves different needs. Manual or semi-auto winders suit low-volume or diverse 

product lines, while automatic stator winding machines are ideal for mass production of identical stators with 

minimal manual labor. (Hub motor stators, discussed below, often require their own specialized machines.)

2. Automatic Stator Winding Machines

Modern automatic stator winding machines use advanced servo drives and CNC controls to deliver 

precise, repeatable coils. Operators program the machine via an HMI (human-machine interface), 

specifying coil turns, taps, and winding patterns. During operation, the machine’s computer controls 

each axis for exact speed and tension, ensuring consistent copper placement and high slot fill. Many 

systems also include automated coil insertion devices (needles, fingers, or magnets) that place wound 

coils into the stator slots immediately after winding, eliminating manual handling.

Key features of automatic stator winders include:

1. Servo-Controlled Axes: Each movement (wire feed, head rotation, carousel indexing) is driven by a servo motor. 

This provides variable speed, smooth motion, and fine tension control, which is crucial for tight coils and high 

slot fill factor.

2. Programmable Winding: Machine programs store parameters like number of turns, skipping patterns, and 

multi-layer arrangements. Changeovers to new stator models simply require loading a different program and 

swapping minimal tooling.

3. Integrated Coil Insertion: Automated insertion stages push or drop coils into the stator's slots in a single step 

after winding. This feature improves cycle time and ensures uniform coil placement. Some machines can also 

automatically cut wire tails and trim ends.

4. Advanced Controls and Monitoring: Built in diagnostics track production counts, detect wire breaks, and can 

measure coil resistance or weight for quality assurance. Touchscreen interfaces allow easy setup of winding 

sequences and adjustment of parameters on the fly.

5. Overall, fully automatic stator winding machines dramatically increase throughput and consistency. They are the 

industry standard for high-volume motor manufacturing, offering rapid winding cycles (often hundreds of RPM) and 

minimal scrap due to precise coil insertion and tension management.

3. Hub Motor Stator Winding Machines

Hub motor stators present unique challenges due to their compact, unusual geometry. In e-bike or 

wheel-hub motors, the stator may be inside or outside the rotor, and coils often have large turn counts 

with one or two turns per coil. A hub motor stator winding machine is specifically designed to accommodate 

these differences. Such machines usually feature a horizontal winding station (if the stator is inside the rotor) 

or a special fixture to hold short, wide stator cores. Key aspects of hub motor winders include:

1. Custom Coil Heads: Hub motor winders may use different head designs (such as linear bobbin insertion 

or ring-winding tools) to fit coils into the small stator space. The winding head might move axially to loop 

the wire around each pole in one or two turns, which is common for hub motor coils.

2. High Slot Fill Capability: Many hub motors use multi-strand wire or parallel winding to improve slot fill factor 

in the limited slot area. The machines support these multi-wire techniques and ensure uniform filling of the 

stator slots.

3. Compact Work Envelope: These winders are built with a smaller footprint or with gates to load and unload 

hub stator assemblies. The automation level (servo drives, PLC control) remains high to maintain consistent 

winding tension and placement.

4. For example, a hub motor stator winder might automatically index each pole position and wind a multi-strand 

coil in a single step, then move to the next pole. Despite their specialized purpose, they still leverage the same 

technologies (servo drives, programmable HMI) as general winding machines. In practice, a hub motor winding 

machine combines the advantages of automation (speed and precision) with tooling adapted for the hub motor's 

short axial length and often thicker wires or coil bars.

4. Key Technical Considerations

When evaluating stator winding machines (manual or automatic), several technical factors significantly 

impact performance:

1. Servo Drive Systems: Modern machines use servo drives rather than mechanical cams. Servo control 

allows electronic adjustment of winding speed and tension for different stator sizes, and it provides 

smoother acceleration. This is especially important for multi-strand or flat-wire windings, where precise 

tension prevents wire breakage and maximizes slot fill factor.

2. Slot Fill Factor: The ability to pack copper into the stator slots affects motor efficiency. Winding machines 

that can handle multiple parallel strands, or even form hairpin/flat-wire coils, tend to achieve higher slot fill. 

When selecting a machine, consider if it supports the conductor type and bundling needed for your fill goals.

3. Coil Insertion Mechanisms: Look at how coils are placed into the stator after winding. Automatic insertion 

(using prongs, vacuum, or simple gravity drop) reduces manual labor and improves consistency. Some 

machines offer a one-step insertion for straight-slot coils, while others use multi-step pivoting arms for 

complex geometries. A robust insertion system is key to high throughput and avoiding damage to delicate coils.

l 4. simultaneously. More axes increase throughput proportionally. However, multi-head machines require 

synchronous servo control on each axis. Also evaluate how many wire feeders or spool holders are available 

if you plan multi-strand winding.

5. Tooling and Changeover: Check how tooling changes are handled. Rapid-change fixtures and programmable 

offset adjustments save time when switching between different stator diameters or pole counts. Some advanced 

machines can auto-adjust winding parameters from a saved recipe, minimizing downtime.

6. These factors (servo-driven axes, slot fill capability, coil insertion design) determine how well a stator winding 

machine will meet your technical requirements. In practice, balance the machine’s capabilities with the 

complexity of your coils and the precision your motor demands.

5. Stator Winding Machine Selection Strategies

Choosing the right winding machine involves matching machine capabilities to product needs and 

production goals. Important selection criteria include:

1. Production Volume and Flexibility: For high-volume, dedicated motor lines, a fully automatic multi-head 

machine delivers the fastest cycle times and lowest labor cost per unit. For smaller runs or multiple motor 

models, a programmable CNC winder or dual-purpose machine may be better, as it allows quicker changeovers 

and handles varied coil geometries.

2. Stator and Coil Design: Evaluate the stator's slot count, coil shape, and wire size. Specialty coils (e.g. pinned 

coils, hairpin bars, or single-turn coils) require compatible winding heads. Make sure the machine's winding 

head type (round-wire bobbin, hairpin feeder, etc.) and fixture system can accommodate your stator's dimensions 

and coil structure.

3. Slot Fill and Performance Targets: If maximizing slot fill is a priority (for high-torque motors), choose a machine 

that supports multi-wire parallel winding or flat-wire handling. Higher slot fill often means using two or more 

thinner wires instead of one thick wire, so confirm that the machine can guide multiple conductors and maintain 

tension on each.

4. Automation and Integration: Consider how the winder will fit into your production line. Some machines offer 

robotic part loading, vision inspection, or interface with MES systems for traceability. Advanced automation 

(like automatic stator transfer feeders) can boost overall output but adds cost and complexity. Plan for any 

needed peripheral equipment (coil transfer loaders, stator indexing tables) that complement the winding 

machine.

5. Budget and Service: Balance initial cost against long-term value. A higher-end machine costs more upfront 

but may pay off in reduced labor and scrap. Also assess the supplier's support: training, maintenance, spare 

parts, and software updates are crucial. Ask about warranties and whether the machine can be upgraded 

(for example, adding a second winding head or Vision QC system later).