In the world of electrical rotating machines, the name Delba Electrical has long been synonymous with innovation and quality. Delba, a renowned company with a rich history, has consistently demonstrated its commitment to excellence through various divisions, and one of the most integral components of this journey is its Copex and coil division. The Copex division is a testament to Delba's dedication to producing high-quality coils for the rewinding of electrical rotating machines. This article delves into the workings of Copex, focusing on its copper extrusion, copper covering and coil forming capabilities.

Quality of Copper Used for Copper Extrusion

The process begins with the acquisition of high conductivity, electrical grade, oxygen-free copper fed through an extruder. The copper is manufactured under controls established by a BVC approved quality management system that conforms with ISO 9001:2008, ISO 14001:2004 and OHSAS 18001:2015 standards.

Copper Testing for Coil Manufacturing

A sample is taken from the extruder at start-up and tested to ensure that the size, profile and elongation are within the required limits. The Vickers Hardness and Springback test is the standard method used to measure the copper softness.

Thereafter a sample is taken from the top of each finished drum and tested. Since the extrusion of the conductor is a continuous process, this sample represents the condition of the wire at the top of its mother drum as well as at the bottom of the subsequent drum. This “snapshot” at the top and bottom of each drum ensures that the quality status of the bare conductor is maintained throughout the manufacturing process of the bare conductor.

Copper Extrusion Machine

Extrusion is a method by which raw copper is transformed into wires with consistent diameters. Delba's high-tech extrusion machines excel at this task, ensuring that the copper wire used in coil production adheres to strict quality standards. They carefully control the copper wire's diameter, allowing for uniformity throughout the entire coil winding process. This uniformity is crucial in ensuring the optimal performance of electrical machines. All our copper conductors comply with the requirements of BS EN 13601:2002 for annealed copper strip.

The extruder is capable of accurately and consistently extruding sizes from 5 mm2 to 120 mm2 for sectional wire. The extruder itself is capable of producing larger sizes but is limited by the availability of the correct rod sizes of an acceptable quality standard for the larger conductors.

Since the output conductor is quenched immediately as it leaves the extruder, it is produced in a fully annealed state and therefore needs no further annealing as is the case with most manufacturers. This results in a quick manufacturing time and fast delivery to customers.

Another advantage of the extrusion process over the drawn process is that the surface hardness usually found on drawn copper owing to the stresses exerted during the cold formation of the section, is eliminated.

Copper Covering Machine for Low Voltage and Medium Voltage Coils

After the extrusion process is complete, the copper wiring is covered with various types of insulation materials specific to design requirements. Delba’s Copex and Coil division uses copper covering machines that expertly enrobe the wire with a thin layer of insulation. This insulation is essential to protect the copper wire and maintain the electrical integrity of the coil.

The copper covering machines used by Delba are engineered to provide a precise and consistent insulation layer which not only guarantees the longevity and reliability of the coil, but also ensures safety in the final electrical product. All covered copper is tested by Delba’s test lab to ensure that the covering of the conductors withstands the required values before being released into production.

Our Copex department has the capability of producing copper conductor with single or multiple layers of taped insulation including paper, NOMEX®, mica, polyester and varnished glass. We also have the capability of producing these insulation coverings in various combinations to our customer’s requirements. The quality of our covered conductors exceeds most customers’ expectations and is rated very highly in the international coil producers’ markets

These machines offer several advantages:

Diverse applications: Delba's copper covering machine is versatile and capable of handling various coil sizes and insulation materials, making it suitable for both low and medium voltage applications.

Precise insulation: The machine ensures consistent covering with precise insulation, reducing the risk of electrical shorts and improving the longevity of the coils.

Quality assurance: Delba follows stringent quality control measures during the covering process, which includes regular testing to meet industry standards and customer specifications.

Coil Manufacturing Shop

With the extruded copper wires covered in insulation, the next step in the manufacturing process is to shape them into the coils that will eventually find their way into electrical machines. Delba’s Copex and Coil division uses advanced coil forming machines to perform this critical task.

Coil forming machines are designed to create coils of various shapes and sizes, tailored to the specific requirements of each motor The precision of these machines ensures that every coil is consistent and perfectly shaped, further enhancing the electrical performance and efficiency of the final products.

Delba’s Copex and Coil division represents a beacon of excellence in the world of electrical coil manufacturing. Our unwavering commitment to precision and quality is evident in every stage of the coil production process, from extrusion to insulation and shaping. The use of cutting-edge extrusion machines, copper covering machines, and coil forming machines is a testament to Delba's dedication to producing coils of unparalleled quality. As electrical machines continues to evolve, Delba's Copex division stands ready to meet the demands of the industry, providing the high-quality coils necessary for the rewinding of rotating equipment.

Dirk van Vuuren

e-mail:  dirk@delba.co.za   |   Web:  http://www.delba.co.za