Spacing Elements
Spacing elements for
transformer insulation design
Spacing elements are essential components in transformer winding assemblies, providing both radial separation between conductors and axial spacing within or between windings. Commonly used in power and distribution transformers, they also serve a critical function in the HV-LV gap to support insulation integrity and cooling efficiency.
Produced from high-quality cellulose-based Transformerboard and insulating papers, the range includes washers, ladders, strips, radial spacers, clack bands, and corrugated board. These elements are available as standard parts or can be custom-fabricated according to detailed customer drawings – ensuring precise fit and performance for every application.
Clackband and Ladder Band
Corrugated Board
Duct Strip
Radial Spacers and Radial Spacer Strips
Weidmann Spacers
Axial Strips and Spacer Strips
Washers and Washer Block Assemblies
Clackband is produced from a kraft paper and Transformerboard T4 bevel strips. When used directly in the winding, clackband facilitates ideal cooling by guiding the oil flow. It is made of trapezoidal blocks and two layers of paper. Because it is already assembled, clackband avoids the possible shearing of spacing blocks and is accordingly easy and safe to handle during the winding process.
Ladder Band is used as a spacer element in oil-filled distribution transformers. It is manufactured from thermally upgraded kraft paper tapes with Transformerboard strips bonded to one side. The kraft paper base is not continuous throughout the entire width of the product. It’s available in various configurations (paper thickness, strip dimensions, and overall width).
Corrugated Board is available in a wide range of profiles. It’s used for decorative purposes as well as electrical applications. The large size of this material and special surface films offer almost unlimited possibilities. It is manufactured from kraft paper, including thermally upgraded paper, with Transformerboard strips bonded to one side. The kraft paper base is not continuous throughout the entire width of the product.
Duct Strip is used as a spacer element in oil-filled distribution transformers. It is manufactured from kraft and thermally upgraded kraft paper with Transformerboard strips bonded to one side. It’s available in various configurations (paper thickness, strip dimensions, and overall width).
Radial Spacers are used to space the individual conductor layers in the windings of power transformers
Radial Spacer Strips are milled from Transformerboard T4 or from laminated Transformerboard T4. Depending on customer needs, the surface screen pattern can be removed in order to guarantee precise compressibility during coil sizing. Radial spacer ends can be punched as well as milled depending on the thickness and customer requirements.
Weidmann Spacers for the radial spacing of windings are made from calibrated strips to ensure accurate final sizing after compression and tryout. Those spacers are free of burrs and available in an almost limitless range of thicknesses. One or two slots in the shapes of rectangular, trapezoidal, or T-slots spacers are milled according to our customers’ needs. Combined with axial strips, these spacers offer an excellent system for spacing copper conductors.
Axial Strips have various functions such as maintaining clearances between coils and phases, maintaining consistent oil ducts, and supporting the spacers. This product group contains different shapes such as rectangular, dovetail, and T-strips. Strips are milled from Transformerboard T4 and TX2, depending on the thickness of the axial strip.
Spacer strips are milled from Transformerboard T4 or from laminated Transformerboard T4. Depending on customer needs the surface screen pattern can be removed (>0.5 mm) to reduce the compressibility of the spacer.
Washers and Washer Block Assemblies provide mechanical support and dielectric insulation from winding to ground. Coil end insulation with washers and blocks is supplied as standard products or according to customer drawings for power transformers. Washers and blocks are made from Transformerboard T4 or laminated Transformerboard TX2.
