Three-phase motor stator winding machine

01

Keep wire tension within the wire maker's limits

MWS Wire Industries publishes recommended winding tensions for round copper and aluminium magnet wire by AWG size, with maximums based on the yield strength of fully annealed copper wire. It warns that tensions above the maximum may cause higher resistance and that the values are recommendations to be checked by your own validation tests that the wire is not stretched in production. [1]

For copper, its table gives AWG 18 a minimum of 4.3 kg and maximum of 5.8 kg, AWG 20 2.7–3.6 kg and AWG 22 1.7–2.3 kg; aluminium wire of the same size has much lower limits, for example AWG 20 at 0.6–1 kg. [1]

Editorial calculation: the AWG 20 copper maximum of 3.6 kg is about 35 N of pull, and aluminium AWG 20's 1 kg maximum about 10 N; a machine running both materials needs tension control that reaches down to the lower range. [1]

Give the supplier the stator drawings (outer and inner diameter, stack height, slot count and shape), wire material, size and grade, number of parallel strands, winding scheme, coils per phase, target fill factor, cycle time, tension range, and how coils are inserted, laced and formed.

02

Choose the winding or inserting method and target fill

Johannes Zerbe's doctoral thesis at TU Berlin (2019) develops needle winding with supporting winding caps, a modification of conventional needle winding in which a changed needle path and specially adapted winding heads allow improved fill factors, and derives design recommendations from feasibility experiments. [2]

The thesis also investigates winding with inductively preheated wire, which softens the copper and uses reversible thermal expansion to reduce cavities under non-circular windings, improving thermal conductivity while allowing reduced wire tension. It further examines how element sizes and scattered material properties affect the accuracy of winding-process simulation. [2]

Editorial note: suppliers on this page offer needle winding, flyer winding and winding-plus-inserting machines; ask each to wind and, if relevant, insert coils on your own stator and report fill factor, wire resistance before and after, and insulation test results.

BBS Automation, a winding machine maker, describes needle winding as the process of choice for internally or externally wound stators and rotors with complex winding schemes, with the needle (nozzle) feeding the wire into the slots. For its vertical needle winders it lists winding speeds up to 600 rpm and wire diameters of 0.1–1.8 mm, with different stator types and winding patterns wound at the same time; its cam-driven needle winders move the stroke mechanically instead of by servomotors, for high quantities with low variance. [3]

Editorial calculation: at 600 rpm a needle lays up to 10 turns per second, so a 60-turn coil on one tooth needs at least 6 seconds of winding time before indexing, terminating and changeover are added. The turn count is an assumed example. [3]

03

Needle, flyer and winding-and-inserting machines from five listed makers

The five makers split by method: Shanghai Wind lists needle winders, Xiamen Sipu flyer winding and inserting machines, Ningbo Nide combined three-winding, one-inserting machines, Xingte single- and multi-station winders, and Grewin winding and inserting machines.

Listings include needle winding machines, single- and multi-station stator winders, flyer winders and combined winding-and-inserting machines.

04

Ask whether coils are compacted after winding, and what it costs

Karlsruhe Institute of Technology (KIT) researchers simulated the compaction of round-wire stator windings, a step that presses wound coils so the round wires are formed towards rectangular shapes and the fill factor rises. They define fill factor as the ratio of the conductor area to the available slot area in the stator stack. [4]

The finite element study used wire of 0.71 mm diameter with five wires per layer, 2, 4 or 8 layers, wild, layer-precise or orthocyclic layer structures, and punch strokes of 7, 14 and 21% of the initial winding height. The 21% maximum comes from converting a round wire into a rectangle of equal area and width, whose height is the diameter scaled by 0.785. The layer-precise winding with 2 layers and a 21% stroke gave the best fill factor, 0.95, but 4% of the original cross-sectional area was pressed out of the slot. At a 21% stroke the wire cross-section shrank about 1.5% more in orthocyclic than in layer-precise windings. [4]

Editorial note: if a supplier offers coil compaction or quotes fill factors near these values, ask for fill factor, resistance and insulation test results on your own stators; the KIT model left out the wire insulation.

05

Pay-off tensioner, needle or flyer head, winding caps and inserting station

In the TU Berlin work, fill factor comes from the needle path and the winding caps that guide the coil, with wire heating as an option that lowers tension. [2]

06

Wire diameter, winding speed and tension limit for a stator winder

Set tension from the wire side: MWS gives 3.6 kg (about 35 N) as the maximum for AWG 20 copper. The needle-winder example covers 0.1–1.8 mm wire at up to 600 rpm. [1] [3]

07

Send the stator, wire and output data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Stator: [drawing; slots; stack height; diameters]
Wire: [copper or aluminium; size; grade; strands]
Winding: [scheme; turns; coils per phase; fill target]
Method: [needle; flyer; wind and insert]
Output: [cycle time; stations]
Quality: [tension range; resistance and insulation tests]

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