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Transformer Design Philosophies
Our transformer design philosophy is based on forty years of experience from
manufacturing transformers for a diversity of applications. Our transformers are used in
professional audio and hi-fi as well as in power supplies, telecommunications, welding,
military applications etc.
We have evolved some unique problem solving strategies when designing transformers,
discussed further below, and we design and build our own production machines in order to
fulfill otherwise unobtainable transformer design goals.
1. Winding technique
Most manufacturers of audio transformers use a conventional bobbin winding system:
Within a transformer section, the copper wire is wound in a more or less "random" fashion,
and thus the voltage difference between two adjacent wires may be substantial. Transformer
sections (such as primary and secondary sections) are separated by isolation film and tape,
but the isolation materials is confined by the same bobbin sides as the copper wire. Static
shields are also confined to the same limits.
The Lundahl Transformers winding technique does not use bobbins. Our open end winding
technique (with insulation between each layer of copper wire within a transformer section) is
consistently applied, even for the smallest transformer types and for the thinnest wire
dimensions. This gives the following advantages:
The wire is wound in well-ordered layers. As a result, no wires are crossed and the fill
factor is increased (in spite of more insulating material!).
As additional isolation is applied in the vertical direction, the isolation is reinforced
where strong mechanical forces and high voltage differences occur.
The copper wire is in close contact with low-voltage neighbors of the same layer only.
Inter-winding capacitance is reduced and reproducible.
Insulation and, if applicable, electrostatic shields are placed between each section,
protruding outside the copper wire edges to improve the insulating capability as well as