Products Description
What Is an Amorphous Ribbon Transformer Core?
An amorphous ribbon transformer core is a wound magnetic core built from iron-based amorphous alloy ribbon - a soft magnetic metal solidified so rapidly that its atoms are frozen in a non-crystalline (amorphous) structure, roughly 25 μm thin. Because there are no crystal grains and no grain boundaries to impede domain movement, the ribbon is a soft magnetic material with very low core loss and low coercivity.
Our cores are wound in three configurations to match transformer topology:
Single-phase amorphous transformer cores - for single-phase distribution and instrument-duty transformers.
Three-phase amorphous transformer cores - three-limb wound cores (AYFA-NE type) for three-phase distribution transformers.
3D wound amorphous transformer cores - closed three-dimensional wound geometry for compact, symmetrical three-phase designs.
They are used wherever no-load loss, energy efficiency and a compact core matter - most commonly in oil-immersed and dry-type distribution transformers.
Why Amorphous Ribbon? (Material Data)
Amorphous ribbon replaces conventional grain-oriented silicon steel in the core, and the reason is in the physics: high resistivity and a non-crystalline lattice cut eddy-current and hysteresis loss. The ribbon's measured properties are below.
| Property | Value | Unit |
|---|---|---|
| Saturation magnetic flux density, Bs | 1.62 | T |
| Density, ρ | 7.26 | g/cm³ |
| Curie temperature | 394 | °C |
| Crystallization temperature | 499 | °C |
| Resistivity | 125 | μΩ·cm |
| Saturation magnetostriction, λs | 27 | ×10⁻⁶ |
| Vickers hardness (50 g load) | 870 | - |
Reading these numbers for a transformer design:
Bs = 1.62 T supports a higher working induction than many soft ferrites, so the core stays compact for a given power rating.
Resistivity of 125 μΩ·cm is far higher than crystalline steel, which is why eddy-current loss is suppressed.
Curie 394 °C / crystallization 499 °C define the safe processing window - the ribbon must be heat-treated below crystallization temperature to preserve its amorphous structure and low loss.
Low magnetostriction (27 ×10⁻⁶) keeps audible noise and mechanical stress sensitivity in check.
Amorphous Ribbon Specifications
| Ribbon model | Thickness (μm) | Thickness tolerance (μm) | Width (mm) | Width tolerance | Lamination factor (%) |
|---|---|---|---|---|---|
| AYFA-N / AYFA-NE | 25 | ±2 | 100–280 | ±2 μm | ≥ 88.0 |
The AYFA-N / AYFA-NE designations refer to the ribbon grade used to build the cores; both are iron-based amorphous alloy ribbon of the specification above.
Ribbon width variants. The cut width of the ribbon is designated S / K / N / T, corresponding to 120 mm / 142 mm / 170 mm / 213 mm respectively. These standard widths set the build width of a wound core and are chosen against the required core window and power rating.
Core Types and Customizable Dimensions
All three core families are wound to order - the sizes below are the customizable working envelope, not fixed stock sizes. Final dimensions are confirmed per drawing.
Single-phase amorphous transformer cores
Single-phase wound cores, supplied with silicon steel sheet reinforcement where the design calls for it. Suitable for single-phase amorphous cores for oil-immersed transformers and single-phase dry-type units.
| Dimension | Min | Max |
|---|---|---|
| A | 120 mm | 1080 mm |
| B | 70 mm | 340 mm |
| C | 29 mm | 155 mm |
| B1 | 128 mm | 650 mm |
Three-phase amorphous transformer cores (three-limb)
Three-limb wound cores (AYFA-NE type) for three-phase amorphous transformer cores in distribution transformers.
| Dimension | Min | Max |
|---|---|---|
| A1 | 140 mm | 1650 mm |
| A2 | 248 mm | 2221 mm |
| B1 | 70 mm | 543 mm |
| B2 | 190 mm | 1358 mm |
| B3 | 290 mm | 1902 mm |
| C | 50 mm | 272 mm |
3D wound amorphous transformer cores
Closed three-dimensional wound cores for compact, symmetrical three-phase designs - a 3D wound amorphous core for dry-type transformers and space-constrained layouts.
| Dimension | Min | Max |
|---|---|---|
| A | 150 mm | 2000 mm |
| B | 130 mm | 1500 mm |
| ΦD | 150 mm | 480 mm |
Product Process of amorphous core and transformer
Single-phase/three-phase core production process
three-dimensional core production process
transformer assembly process
1. Prepare coil
2. Prepare amorphous cores
3. Open core lapjoints
4. Combine core and coil
5. Close core lapoints
6. Attach other parts
7. Amorphous transformers
Typical Excitation and Core-Loss Performance
Every core family is supplied with its excitation and core-loss curves measured against induction, at both 50 Hz and 60 Hz.
Single-phase and three-phase cores - excitation (VA/kg) and core loss (W/kg) curves plotted against induction across the typical working band.
3D wound cores - exciting apparent power (VA/kg) and core loss (W/kg) curves across the working induction range.
Frequency behaviour - as expected, the 60 Hz curves sit above the 50 Hz curves; select the curve matching your grid frequency.
The defining commercial advantage is ultra-low no-load loss: because amorphous ribbon has no grain-boundary pinning, core loss at typical operating induction runs far below a comparable grain-oriented silicon steel core. The exact figures for a given core are read from its curve set and confirmed on the datasheet.
Applications
Oil-immersed distribution transformers - high-efficiency amorphous cores for utility and industrial distribution.
Dry-type distribution transformers - compact 3D and three-phase wound cores for indoor and fire-sensitive locations.
Single-phase transformers for pole-mounted and rural distribution.
Reactors and inductors requiring low loss and stable inductance.
Instrument and specialty transformers where low excitation current matters.
Amorphour transformer core
Wasted transformer
New amorphous transformers
Wasted core
Customization & Ordering
Amorphous ribbon cores are built to order - there is no standard size list. To quote a custom amorphous transformer core, confirm:
Core type - single-phase, three-phase (three-limb) or 3D wound.
Dimensions - window and build dimensions within the envelopes above.
Ribbon grade and width - AYFA-N or AYFA-NE; S / K / N / T width (120 / 142 / 170 / 213 mm) or a specified cut width.
Rated power, voltage class and frequency - 50 Hz or 60 Hz.
Loss / excitation target - the required no-load loss and excitation limits per your efficiency class.
Application - oil-immersed or dry-type, and any dimensional or mounting constraints.
Because each core is wound and heat-treated to the confirmed specification, dimensions, grade and quantity are confirmed per order. Provide the drawing and required quantity and we will confirm feasibility, MOQ and lead time.
Quality & Standards
Ribbon material - iron-based amorphous alloy ribbon per GB/T 19345 (amorphous and nanocrystalline soft magnetic alloy strips).
Cores are built for use in transformers tested to the applicable transformer standards (e.g. IEC 60076 series) per the customer's design.
In-process checks - ribbon thickness and width tolerance, lamination factor (≥ 88.0%), core dimensions and window squareness, and heat-treatment record against the crystallization limit.
Final verification - excitation current, core loss and no-load performance verified against the supplied curve set.
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FAQ
What is the difference between single-phase, three-phase and 3D amorphous cores?
They differ in winding geometry, not material. Single-phase cores serve single-phase transformers; three-limb wound cores serve standard three-phase distribution transformers; 3D wound cores use a closed three-dimensional geometry for compact, symmetrical three-phase designs.
Can I get a custom amorphous transformer core size?
Yes - cores are wound to order. Supply the window and build dimensions within the envelopes above, and the size is confirmed per drawing.
Why is amorphous core no-load loss lower than silicon steel?
Amorphous ribbon has no crystalline grains or grain boundaries and much higher resistivity, so hysteresis and eddy-current loss are both reduced, giving ultra-low no-load loss at typical operating induction.
What ribbon widths are available?
Standard cut widths are S / K / N / T = 120 / 142 / 170 / 213 mm, within an overall ribbon width range of 100–280 mm.
Is the core suitable for oil-immersed and dry-type transformers?
Yes - configurations are supplied for both oil-immersed and dry-type distribution transformers. Confirm the application when ordering so the build and reinforcement are set correctly.
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