Transforming Energy for America

Coil Winding

In a core-type power transformer, the most common types of windings are continuous discs for high voltage and helical for low voltage.

The winding of disc-type coils is complex. The turns are wound in sections or discs – the first turn is wrapped around the cylinder and the number of turns will be wound over this first turn, producing a disc section whose thickness is equal to turn width. The outside turn of this section is carried over to the next position. The turns now proceed from outside to inside; the turns are first wound from inside out and the section is then turned over by hand, without turning the coil lathe. The inside turn becomes the start of the next section, and the process is repeated until the coil is finished.

The complete coil consists of many disc sections wound from a continuous copper conductor without brazed joints. Radial spacers and washers separate the discs. Extremely skilled and experienced winders are required for this process to reduce the margin of error.

At VTC, we have made significant investments in automated winding machines to eliminate human errors. Our machines have an on-line computer keeping track of the number of turns. A robotic arm ensures the turns are aligned and tight and tensions on incoming copper conductors are calibrated automatically. Our automated winding machines ensure reliability while reducing labor at the winding station.

VTC has multiple horizontal and vertical winding machines.

(Pictured below on the left is an example of a horizontal winding machine, and the picture on the far right shows an example of a vertical winding machine used for our larger units.)