Wires and protective sheaths for wiring machine tools

PV, PGV, PMV, PMOV brands PV, PGV, PMV, PMOV, vinyl-insulated power cables VVG, control cables KVVG and KVRG are often used for the installation of machine wiring. Due to oil resistance, moisture resistance, high mechanical strength and external color, these wires and cables meet all requirements for installation on metal cutting machines.

Wires with rubber insulation can be used only exceptionally, in the presence of lacquered braid.

The general technical conditions do not allow the use of wires with a cross-section of less than 1 mm on metal-cutting machines.2, only as an exception, the use of wires with a cross-section of 0.75 mm2 was allowed for the installation of blocks. However, with the increase in volume and complexity of the electrical equipment of metalworking machines, as well as in connection with the widespread use of in modern electronic machines and microprocessor devices became completely inevitable unlimited use for installing low-current circuits of wires with a cross section of 0.75 mm2, and on panels and in blocks — even 0.5 and 0.35 mm2.

Pipes, metal hoses, elastic pipes, hoses and bushings are used to protect the wires. The most commonly used for these purposes:

• steel water and gas pipes for the installation of fixed electrical cables on the machine and the installation of external electrical wires on the base,

• flexible non-hermetic metal hoses with cotton gaskets for the installation of internal electrical wires and the installation of movable electrical wires in short sections,

• flexible sealed metal hoses in braided tinned copper wire with asbestos sealing for installation of wires and cables in conditions of industrial humidity,

• pressure hoses made of rubber fabric for the installation of electrical wires to the moving parts of the machine,

• PVC pipes made of heat-resistant plastic for mounting electrical wires to moving parts of the machine, terminating wires in places where insulation is exposed (see also — high polymer dielectrics).

With the development of machine wiring, the use of metal hoses is being reduced more and more and the use of vinyl pipes, both thick and thin walled, is expanding.

For electrical wiring, pipes that do not have internal irregularities, protrusions and irregularities, without scale and dust can be used. And pipe bends must have the correct shape, without depressions. Before laying, the inner surface of the pipes is covered with quick-drying varnish or paint.To avoid damage to the insulation of the wires, chamfers are removed from the inside of the edges of the pipes.

It is recommended to produce special protective sheaths for machine wiring: thin-walled metal pipes covered with a thin layer of insulating varnish on the inner walls, reinforced flexible vinyl pipes.

The applicability of pipes and hoses for electrical wiring is normalized in the enterprise with a possible limitation of the nomenclature and sizes. It is also possible to recommend the release of normals for straight pipes and original nipples of different lengths, with a threaded thread on one or both ends. The normalization of the bending radii of the pipes allows the application and better use of the technological equipment.