Electric motor stator lamination stack

01

Choose the electrical steel grade, thickness and lamination factor

Nippon Steel's non-oriented electrical steel table cross-references its grades to IEC 60404-8-4 and Chinese GB/T 2521: for example 35H270, M270-35A and 35W270 all mean a maximum core loss W15/50 of 2.70 W/kg (at 1.5 T, 50 Hz) in 0.35 mm steel. Its 0.35 mm grades range from 2.10 to 4.40 W/kg with a lamination factor of at least 95.0%, and its 0.50 mm grades from 2.30 to 8.00 W/kg with at least 96.0%; 35H270 also guarantees an induction B50 of at least 1.64 T and has an assumed density of 7.65 kg/dm³. Tests follow JIS C 2550 on as-sheared specimens. [1]

Editorial calculation: a 100 mm stack of 0.35 mm laminations at a 95% lamination factor contains about 0.95 × 100 ÷ 0.35 ≈ 271 laminations and about 95 mm of steel; at 0.50 mm and 96% it is about 192 laminations. A 5 kg core of a 2.70 W/kg grade has a guaranteed material loss of no more than about 13.5 W at 1.5 T and 50 Hz; that is a material figure, so ask the supplier how cutting and stacking affect the finished core. [1]

Give the supplier the lamination drawing, steel grade and thickness, coating, stack length and tolerance, stacking method, slot and bore tolerances, skew, quantity (prototype or series), insulation coating or epoxy, and inspection required.

02

Choose the stacking method

Lamination suppliers describe these ways to join laminations: interlocking points formed in the progressive die so laminations self-stack; MIG, TIG or laser welding along the stack; riveting and cleating; glue bonding; and self-bonding, where laminations coated with a bonding agent are joined by heat and pressure. [2] [3]

Lam365 writes that “Motor core laminations generally range in thickness from 0.2mm to 0.5mm”, with thinner laminations improving electromagnetic performance but reducing mechanical strength, and offers laser cutting and wire EDM for prototypes before stamping dies are built. [4] Ask each supplier which method suits your volume and how dimensions are checked; one states 100% CMM inspection of prototypes. [5]

03

Stamped, laser-cut, interlocked, welded and bonded stacks with prototyping

Lamnow, Motorneo, Lam365, Lammotor and Lamistacks list stamped, laser-cut, interlocked, welded and bonded lamination stacks with prototyping; JYSTATOR lists brushless motor stator laminations with interlock, bonding and laser welding options; New Ruichi lists stepper motor stator and rotor core assemblies.

04

Electrical steel, insulation coating, joining method, slots and bore, and surface treatment

Grade and thickness are bought from the steel maker, the joining method from the stack maker: Nippon Steel's grade sets the guaranteed core loss, while interlocking, welding or bonding is chosen with the lamination supplier. [1] [2]

05

Stack length, thickness, stacking factor, core loss and tolerances for a lamination stack order

Stack length and stacking factor set the lamination count: 100 mm of 0.35 mm steel at Nippon Steel's 95% minimum is about 271 laminations (editorial calculation). [1]

06

Send the drawing, steel and stacking data together

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

Drawing: [lamination; slots; bore; OD; skew]
Steel: [grade; thickness; coating]
Stack: [length; lamination factor; method]
Tolerances: [length; bore; slots; flatness]
Quantity: [prototype; series volume]
Inspection: [CMM; loss test; certificates]

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