Magnet wires are used in the construction of transformers, motors, generators and other applications that require tight coils of insulated wire, both round or flat.
The choice of the insulating tapes depends on the performance (in term of dielectric insulation, thermal protection, mechanical resistance) required for the final product, according to the the various applications: mica, polyester, polyimide, kraft paper and others.
The construction of the magnetic cable insulation suitable for high-performance motors and generators requires the deposition of several tapes (typically mica-polyester tapes), each of which is laid without overlapping (no butlapp). The process requires that each successive tape is laid according with a well-defined and constant deviation with respect to the previous one.
Historically, this process is obtained with tangential taping heads which allow the application of several tapes at the same time in the same taping point. However, this process involves low speed and reduced autonomy, due to the frequent replacement of the tape pads.
WTM has developed a specific technology for this kind of application, which allows the synchronization of several concentric taping heads (that works at high speed), each one equipped with a tape spool (that offers greater autonomy). Synchronization takes place through the VISIO SYSTEM, a fully integrate control system provided by one or more high-speed cameras that continuously monitor and adjust - in close loop control - the positioning of the tape applied by one taping head with respect to the tape placed by the previous one. It is a high performance and automatic production cycle, whose high precision reduces errors and waste.
The layout of the taping line for magnet wire is composed by:
- traversing pay-off, with wire tension managed by torque control;
- straightening and cleaning unit, for the preparation the wire;
- taping units (up to four) with fully motorized taping heads, equipped with WTM dynamic dancer that guarantees a stable and constant application of tape over the wire;
- Visio System and control software for adjusting the position of each tape application compared to the previous one;
- pulling system with two caterpillars, that control the line speed and cable tension;
- laser gauges and spark tester for in-line quality control;
- take-up unit, with wire tension managed by dancer or torque control, and wire guide by traversing movement;
- paper feeding device, installed on the take-up, that automatically applies a paper layer on the reel during the cable winding.