Lamination stacks are assemblies of thin, insulated metal sheets, typically made from either nickel alloy, cobalt alloy, or silicone/electrical steel, that are stacked to form the magnetic stator or rotor cores in generators. These lamination stacks play a crucial role in converting electrical energy to mechanical energy efficiently, and they minimize energy loss from eddy currents and hysteresis.

Thinner laminations are especially important, as they deliver higher performance, particularly under high-frequency and high-torque conditions that are vital in renewable and nuclear energy generator applications.

To maintain density and performance, precise stacking control, including tolerances of ±1 lamination height and feature alignment to ±0.0001 in., is essential, as stack density directly impacts magnetic integrity. This is because rough or misaligned edges on each layer increase air gaps and eddy current paths, leading to energy loss even at a 1-2% reduction in packing factor.

To ensure the efficiency of your lamination stacks, Thomson Lamination Co. (TLC) optimizes stacking with bonding, riveting, and welding tailored to application needs. The result is structurally stable and precise stacks with consistent lamination density and dimensions. Keep reading to learn more about material selection, coating options, and our capabilities for the energy industry.

Material Selection for Power Generation Applications

Thomas Lamination Company works with many magnetic alloys that are compatible with energy industry applications. Choosing the best material for the project comes down to specifications, operating conditions, cost considerations, and other factors. Material options include:

  • Non-oriented electrical steels. Also referred to as silicon steel, electrical steel is a cost-effective and versatile material widely used in the energy industry due to its reliable magnetic performance in generators and transformers. Its silicone-enhanced structure also reduces eddy current losses, which enhances efficiency and makes electrical steels the standard material for many electric motors and generators.
  • Cobalt-iron alloys. For applications that require high power density, cobalt-iron alloys are often the material of choice. They provide 20-30% greater flux density, which helps in building compact and efficient cores. These alloys are also known for their excellent wear and corrosion resistance, making them ideal for heavy-duty applications.
  • Nickel-iron alloys. Nickel-iron alloys have low core losses and stable permeability for a variety of renewable and nuclear energy generation applications.

Assembly and Coating Options

The individual metal layers that make up lamination stacks are coated with insulating materials that insulate the layers from each other, block paths that form eddy currents, manage heat, and maintain optimal performance.

Bonded, riveted, or welded stack assemblies strengthen mechanical integrity and vibration resistance, both of which are critical for generator reliability in the energy industry. The stacking factor, which is typically around 0.95, reflects efficient use of core material while maintaining insulation thickness. At TLC, we ensure that stacks are meticulously coated and bonded for optimal magnetic path continuity and extended service in high-stress environments.

Rotor and Stator Lamination for the Energy Industry by TLC

At Thomas Lamination Company, we maintain an in-house library of over 1,500 dies and can manufacture custom dies as well. We have multiple high-speed presses with capacities up to 250 tons, and can run dies up to 36 by 72 in. Our capabilities include prototyping as well as small and large volume production.

In addition to stamping laminations, we also offer annealing, stator and rotor assembly, grinding, and optional coating, which can prevent insulation cut-through from voltage spikes.

Whether you need precision lamination stacks for compact renewable systems or critical nuclear circuits, TLC is here to help with stamping, assembly, and annealing services. Contact us to discuss your energy generation application, or request a quote today.