Can CRGO lamination be used in motors? Pros, cons, and niche cases

Short answer for busy purchasing and design teams

Yes, Laminazioni CRGO can be used in motors. But not the way you’d drop-in swap material in the BOM and call it done.

In standard induction or PM motors with conventional stator/rotor stacks:

• Using CRGO senza redesign usually hurts performance: higher localized losses, earlier saturation in some regions, more torque ripple, less predictable noise.
• Most commercial motors stay with non-oriented silicon steel because the magnetic field in the core rotates; they need near-isotropic behavior in the sheet plane, which CRGO simply does not have.
• CRGO in motors only starts to make sense when you deliberately shape the flux paths and stack geometry so the flux mostly follows the rolling direction in each piece (segmented stators, shifted stacks, axial flux, etc.).

So the practical rule:

CRGO is not a drop-in upgrade for standard motor laminations. It’s a tool for special topologies and high-efficiency prototypes, when design and manufacturing can support the complexity.

Why motors usually stay with non-oriented electrical steel

Very short recap, without textbook diagrams.

• In transformers, flux stays mostly along one straight path.
• In motors, flux keeps turning: teeth, yoke, slot openings, rotor geometry. The local magnetization direction swings over the electrical cycle.

Grain-oriented steel is manufactured so that the “easy” magnetization direction lines up with the rolling direction. Along that direction, you get low loss and high induction; perpendicular to it, loss and permeability degrade sharply.

Non-oriented steel spreads its performance more evenly. Loss is higher than CRGO along the best direction, but much better than CRGO when the field is off-axis. That’s why data sheets and handbooks keep saying:

• CRGO → static cores (power/distribution transformers).
• CRNO/CRNGO → motors, generators, rotating machines. 

Your motor flux path is not one neat arrow. It’s more like a loop that forgot to stay in a plane.

That’s the core reason.

What actually happens if you specify CRGO for a motor lamination stack

Let’s assume a common case: a radial-flux AC machine, slotted stator, conventional rotor. You ask your lamination supplier to punch the same geometry in CRGO instead of CRNGO.

1. Magnetic behavior in the actual built core

On the CRGO datasheet, you see impressive low loss at 1.5 T, 50/60 Hz along rolling direction. All good.

Inside your motor:

• Denti see flux mostly along their length, but not perfectly aligned everywhere.
• Yoke runs circumferentially. Parts of that path will be aligned; other parts will be skewed relative to the rolling direction depending on how your blanks were nested.
• Around slot openings, notches, and bridges, flux lines cut across the rolling direction in messy ways.

Result:

• Regions aligned with rolling direction behave as advertised.
• Regions off by 45–90° see higher local core loss and lower permeability than you expected.

Design tools that assume isotropy under-predict that mess. FEA models with proper anisotropic BH and loss data can show it, but most legacy motor models don’t carry full directional loss surfaces.

So you get something like:

• Global efficiency may not improve.
• Iron loss distribution becomes uneven, hotspots appear.
• Torque ripple and acoustic behavior shift in ways you didn’t plan for.

2. Loss and temperature map

Academic and industrial studies that tried GOES stators in AC machines often report:

• Iron loss reduction is only achieved when laminations are shifted or segmented so the flux can keep finding an easy direction across layers or segments.
• With “simple” stators made from CRGO cut like NO steel, the gain is small or even negative.

In one 10 kW induction machine example, switching to shifted GO stator laminations improved efficiency by about 2 percentage points, but that relied on carefully chosen shift angle and anisotropic modeling in the design flow.

So CRGO can help, but only if you let the geometry take advantage of it. Just changing the grade code in the spec doesn’t give you that.

3. Manufacturing and stack build

Purchasing usually feels the pain here first.

• Spessore
  • Many CRGO grades for transformers are 0.23–0.27 mm.
  • Standard motor CRNGO grades tend to run 0.35–0.50 mm, sometimes 0.65 mm for cost-driven designs.
  • Thinner sheet is good for loss but demands tighter tooling control, better flatness handling and different press settings.
• Punching and burr control
  • CRGO can be more sensitive to mechanical stress; edge damage hurts the very properties you paid for.
  • Burr height specs might need to tighten, or you lose much of the benefit through extra loss and noise.
• Orientation control
  • You now care about how every individual blank is oriented relative to the rolling direction.
  • That means more complex nesting, potentially lower sheet utilization, and stricter traceability for each coil.
• Rivestimento e fattore di impilamento
  • Many CRGO coils arrive with coatings optimized for transformer strip cutting and stacking, not for high-speed motor stamping lines. Coating choice directly influences stacking factor, interlaminar resistance, punch wear, and risk of laminations sticking.

All of this pushes cost and production risk up. Sometimes more than the watts you’re trying to save.

4. Cost and supply chain

Even leaving physics aside:

• CRGO is typically more expensive per kg than motor-grade CRNGO at similar silicon content, due to tighter processing routes.
• Coil widths and logistics are aligned to transformer markets. Motor lamination dimensions and volumes may not match what mills like to roll and slitting lines like to run.
• You might end up with “non-standard” MOQ and longer lead times, especially if you want specific thickness + coating + grade combinations optimized for motor use.

So if your design doesn’t squeeze clear performance out of CRGO, purchasing is left paying more for a harder-to-make stack that doesn’t obviously improve the motor’s datasheet.

CRGO vs CRNO/CRNGO for motors — quick comparison

From a motor-focused viewpoint only:

Niche motor cases where CRGO starts to make sense

This is where things get interesting for engineers looking for that extra few percentage points and willing to accept complexity.

1. Shifted GO laminations in induction machines

Several research groups have tested stators made of GO sheets, stacked so that each lamination is rotated by a fixed angle relative to the previous one.

The idea:

• Each layer’s rolling direction points somewhere else around the circle.
• Flux is encouraged to “hop” from lamination to lamination and stay near an easy direction in each layer, instead of fighting the hard direction in a single sheet.

Reported results include:

• Measurable reduction in core losses compared to equivalent NO stators at the same thickness.
• Efficiency gain in the order of a couple of percentage points for medium-power induction machines.

But it comes with:

• Complex stator build, since each lamination has its own angle.
• Tougher stacking and alignment process.
• More sensitive quality control — misalignment ruins the concept.

This is not something you do casually on a commodity motor line. It fits better in specialized high-efficiency products where volume is modest and every watt matters.

2. Segmented stators with CRGO teeth

Modern concentrated-winding PM machines already use segmented stators for other reasons (assembly, copper fill, thermal paths). That architecture is convenient if you want to experiment with GO just in specific parts:

• Teeth made from GO, oriented so flux during operation follows the rolling direction.
• Yoke pieces from NO steel, which handle more complex flux paths.

Studies on such machines show:

• Reduced iron losses compared to all-NO designs.
• Gains mainly in regions where flux is well aligned to the GO teeth.

Design trade-offs:

• A lot of additional cutting edges and interfaces → parasitic gaps, extra reluctance, and more surfaces to manage mechanically.
• Tooling: separate dies or cutting processes for teeth and yoke, different materials, different handling rules.

So this is a realistic candidate when you already like segmented stators for other reasons. Then GO teeth become another knob to tune.

3. Axial-flux and special reluctance machines

Axial-flux topologies and some switched-reluctance or flux-switching machines have flux paths that are more planar and can be aligned with rolling directions in clever ways.

Ad esempio:

• Axial-flux switched reluctance machines with GO rotors show improved torque per volume compared to NO rotors, because much of the rotor path can follow the easy direction.
• Certain PM synchronous motors with anisotropic stator cores (split yoke/teeth) show iron loss reductions on the order of 5–15% when GO is used correctly.

Again, this is not just a material choice. The entire electromagnetic design is tuned around anisotropy — including rotor/stator geometry and control strategy in some cases.

4. High-speed traction motors with tuned flux paths

At very high speeds (tens of thousands of rpm), iron loss often dominates. Some traction motor concepts use thin GO cores in carefully shaped structures to reduce loss at operating induction.

Typical characteristics:

• Thin laminations (≤0.23 mm) to cut eddy currents.
• Flux paths arranged so high-frequency components stay close to rolling direction.
• Very strict manufacturing controls; even small deviations in orientation or stress can erode the performance gains.

These are niche designs, usually in R&D or premium products, not catalog IE3 frame motors.

5. Hybrid cores and wedges

You also see proposals where CRGO appears as:

• Local inserts or special wedges in high-flux regions.
• Parts of a segmented rotor or stator where flux direction is well-defined.

This approach tries to get some benefit without rebuilding the entire core from GO. But:

• Magnetically, you now have interfaces between materials with different permeabilities and saturation behavior.
• Mechanically, those inserts must survive slotting, assembly, and vibration.

It can work, but every extra material boundary is another way to lose predictability.

Practical checklist for purchasers and engineers

If someone proposes CRGO for a motor lamination stack, treat it as a design project, not just a sourcing change.

Here are the questions to walk through.

1. Flux pattern and topology

• Does the machine topology allow most of the flux in each lamination piece (tooth, segment, rotor pole) to follow a clear direction?
• Do you have anisotropic BH and loss data in your simulation tools, or will you be guessing?
• Are you prepared to adjust tooth/yoke geometry or go segmented/shifted to exploit the material?

If the answer is “no” on those, you’re mostly buying trouble.

2. Material and coating

• Which exact grade and thickness of GO are you considering? (Not just “M3”. Actual mill spec, thickness, and coating.)
• Is the coating suitable for your punching line, stacking method, and any post-processing (stress relief, bonding, welding)?
• What stacking factor will you see in real production, and how does that change your effective slot area and back-iron thickness?

3. Tooling and process capability

• Can your current presses, dies, and maintenance practices keep burr height and edge damage inside a tighter window?
• Can your nesting respect rolling direction for every piece without wrecking material yield?
• How will you validate rolling direction and orientation at incoming inspection?

4. Cost and risk

• What is the per-motor cost delta at expected volumes (material + tooling + yield)?
• Is there a credible path — simulation plus prototype test — that shows a tangible gain in efficiency, torque density, or temperature?
• Does the business case tolerate a few prototype cycles while you learn how GO behaves in your specific stack and process?

If after this exercise the benefits still look solid, GO might be worth piloting. If not, high-grade CRNGO or thinner NO laminations are usually a simpler lever.

FAQ: CRGO laminations in motors

Sintesi:

Laminazioni CRGO può be used in motors, but only profitably when the electromagnetic design and manufacturing flow are built around anisotropy. For the majority of industrial and EV motors, high-grade non-oriented electrical steels remain the practical choice.