Lamination Stacks for Fan Motors Manufacturer

The choice of magnetic material is basic to how well fan motor core laminations work. At Sino, we carefully choose and test materials based on their magnetic and mechanical properties, making sure they work best for specific fan motor uses.

Rules for Choosing Materials: Our selection process looks at:

• Core Loss: Reducing wasted energy from hysteresis and eddy currents.
• Permeability: How well the material can support a magnetic field.
• Saturation Flux Density (Bs): The most magnetic field the material can handle, which directly affects power density.
• Yield Strength and Mechanical Strength: Important for the making process and for lasting a long time.

Key Material Types and Their Properties:

• Silicon Steel Grades:
  • High-silicon, low-loss electrical steels (e.g., M235-35A, Nippon Steel’s Super Core) are what we usually use for high-efficiency applications.
  • We use extra-thin gauges, usually 0.18–0.23 mm, which lower core losses by 10–15% compared to standard 0.35 mm laminations. This also helps lower noise caused by magnetostriction.
  • For high-speed fan motors, we can make silicon steel laminations as thin as 0.10 mm.
• Amorphous Alloys:
  • What they’re made of: Usually iron-based (e.g., Metglas 2605SA1, 2605HB1M, VAC 6025X).
  • Core Loss: Have much lower core losses than regular silicon steels, especially at frequencies above 1 kHz (0.2–0.4 W/kg at 1.5 T, 1 kHz).
  • Saturation Flux Density (Bs): Around 1.56 T for Metglas 2605SA1, though often limited to ~1.2 T in use because of sensitivity to stress.
  • Permeability: Starting permeability (μi) around 40,000 at 1 kHz.
  • Mechanical Properties: Naturally brittle, which makes it hard to process into thin laminations (<25 μm) and means they can crack easily during stamping or winding.
  • Cost: Usually cheaper than nanocrystalline alloys because they are made in a simpler way (one quick cooling step).
  • Thermal Stability: Can break down above 120°C, which limits their use in high-temperature places.
  • Best for: Good for small to medium power fan motors (<5 kW) where cost and low loss are important, and mechanical stress is not too high.
• Nanocrystalline Materials:
  • What they’re made of: Fe-based with B, Si, Nb, Cu (e.g., Hitachi Finemet FT-3M, FT-8M, VITROPERM 500F).
  • Core Loss: Show low core losses, and their advantage becomes clearer at frequencies above 10 kHz, where losses can be 20–30% lower than amorphous metals.
  • Saturation Flux Density (Bs): Generally higher (1.2–1.3 T for Finemet-type alloys), allowing for smaller core designs or higher power densities.
  • Permeability: Much higher starting and maximum permeability (μi > 100,000 at 1 kHz), leading to better magnetic response and lower magnetizing current. This is good for high-frequency, low-loss uses.
  • Mechanical Properties: While also brittle, they can be made less so with the right heat treatment, offering better strength for complex core shapes and easier handling.
  • Cost: 30–50% more expensive than amorphous metals because of an extra heating step, though the price difference is getting smaller.
  • Thermal Stability: Keep their magnetic properties up to 130–150°C, with some types stable up to 180°C, making them good for high-temperature fan motor environments.
  • Best for: Used more and more in high-power (>5 kW), high-frequency uses (e.g., industrial HVAC, EV cooling fans) where higher Bs and thermal stability are needed.

Advanced Testing Methods: Sino uses advanced methods to ensure material quality and performance:

• Magnetic Property Testing: Using Epstein frames and single sheet testers to measure core loss, permeability, and saturation flux density under different frequency and flux density conditions.
• Mechanical Testing: Checking yield strength, hardness, and ductility to guess how the material will act during stamping and assembly.
• Microstructural Analysis: Using scanning electron microscopy (SEM) and X-ray diffraction (XRD) to check the grain structure and find any flaws.

Hybrid Lamination Stack Approaches: Knowing the unique benefits of different materials, Sino is actively looking at and using hybrid stacks. These combine amorphous and nanocrystalline layers to balance cost, loss, and mechanical properties. Recent research shows that such hybrid solutions can lower total core loss by up to 15% and improve mechanical strength, especially for motors running in the 1–10 kHz range. This lets us create solutions that offer the best of both worlds for our partners’ specific needs.

New Processing Methods: We are always investing in advanced post-processing methods, like pulsed laser annealing and additive manufacturing of soft magnetic composites, to further lower core loss and improve ductility, pushing what materials can do.

By offering a wide range of materials and using careful testing, Sino makes sure our partners get the best lamination solution for their fan motor applications, balancing how well it works, how much it costs, and how easy it is to make.