What Are Electrical Steel Coatings?

Electrical steel coatings are pigmented coatings that insulate silicon steel sheets of motors and generators. To ensure the efficiency of motors or generators, a material that can be magnetized and demagnetized is needed. Electrical steel meets this requirement perfectly.
The waterborne, heat-curing electrical steel coating is the next key factor in the efficiency of motors and generators. This is required for the construction of the magnetizable core. The coating’s main function is to insulate the electrical steel sheets in order to prevent the flow of electricity and to reduce the eddy current. Electrical steel coatings also serve to lengthen the shelf life of the required punching tools.

Voltatex® electrical steel coatings limits the core losses and offers excellent increased efficiency in motors, generators and transformers. Axalta offers a complete range of high-performance varnishes that meet the C3, C5 and C6 insulation classes according to the AISI-ASTM A 976-9 standards.

What Are the Different Insulation Classes?

  • C3 / EC-3:
    These are unfilled, organic-based varnishes that deliver increased punchability and have exceptional insulation properties. Typical applications for these coatings are small motors, transformers and transmitters.
    A special C3 coating is the Voltatex self-bonding varnish, which shows the highest level of adhesive properties thanks to its adherence over the whole cross-section, even of complex geometries. It enables electrical device manufacturers to insulate and to adhere steel sheet stacks in one step while still retaining the magnetic properties and the excellent mechanical strength of the electrical steel.
  • C5 / EC-5:
    These are filled organic- and inorganic-based varnishes ideally used for increased insulation properties, resistance against annealing and improved weldability. Typical applications for these coatings are machines undergoing treatments like welding, Al-die casting or annealing.
  • C6 / EC-6:
    These are highly-filled organic- and inorganic-based varnishes that deliver increased insulation properties as well as the required resistance against pressure. Typical applications for these coatings are medium and large machines with high resistance against pressure and temperature.

These high-performance insulation varnishes are mainly applied with coil coating technology and are fast cured in a tunnel oven. This process allows for increased, high-quality production.

All Voltatex electrical steel coatings are suitable for high-speed curing, which is mandatory when using NIR technology or inductive curing. For our customers, the excellent adhesion and extraordinary elasticity of the varnishes result in efficient use of punching and cutting tools. Voltatex bonding enamels and special electrical steel coatings are a technically sophisticated solution for full-faced, permanent adhesion of laminated steel cores.