17 Dec All You Should Know About Cables And Assemblies
Cables are an integral part of all circuitry and appliances that we use today. These cables can be used individually in a small simple device, or as a cable assembly comprising of multiple cables grouped together to work in complex equipment. A cable is a rod or coil of wires with many times the diameter required for the finished product. This rod or coil is drawn through a series of dies that reduce the diameter by a set percentage with each die, to bring to a size that is required. However, with the diameter decreasing, the length increases, thus keeping the volume of the wire just the same.
Wires come in solid or stranded designs that are generally circular in cross-section, with other available options being square, rectangular, and hexagonal. A solid wire is easy to manufacture, but has a smaller cross-section and lesser flexibility than a stranded wire. Stranded wires are made up of multiple small wires bundled together to form a large conductor. This gives them greater surface area and makes them more flexible, thus making them a better conductor as compared to a solid wire. More the number of wires, more flexible and break-resistant the cable. The lowest number of wires used to produce such cables is generally 7 with one in the middle, and 6 surrounding that one.
There are many different types of strands that can be employed when manufacturing a stranded conductor. You can get all kinds of cables and cable assemblies at Miracle Aerospace, the leading cable assembly manufacturers in India, who is engaged in various Make In India projects like fighter jets, helicopters, cockpits, missile launchers, light transport vehicles, and more.
- Concentric strand – This consists of a central wire surrounded by one or more layers of helically laid wires. Each layer has six more wires than the previous layer; and each layer is applied in a direction opposite to the layer under it.
- Bunch strand – This consists of a collection of strands twisted together in the same direction without regard to the geometric arrangement.
- Rope strand – This consists of a collection of concentric stranded groups that are twisted together.
- Compact strand – This consists of layers stranded in the same direction and rolled to a predetermined ideal shape. The final product is a conductor smaller in diameter, smoother on the surface, and containing no interstices or air spaces.
When these cables are combined together, they form cable conductors that are supplied as both bare conductors with no coating, and with coatings. The most common materials used for coating include silver, tin, and nickel.
- Silver coating is used in high temperature environments and in high frequency applications.
- Tin coating is the most common coating used to improve corrosion resistance and solderability, and reduce friction between strands.
- Nickel coating is used in applications where temperature is over 200°C; however, along with higher electrical resistance, nickel exhibits poor solderability.
However, different environments call for specialized compounds that can withstand high temperature applications, and allow high current carrying ability. In addition, conductors are also insulated with polymer or plastic to provide isolation from other conductors and the environment to prevent short circuits.