Improving the Reliability of Protective Elements for Electrical Networks

Metal cable trays are considered an indispensable component of modern electrical networks. Their significance is quite important and comparable to the significance of any cable system as a whole. It is impossible without a tray system to connect the power supply system, distribute low-current systems, arrange the well-coordinated work of air conditioning and ventilation, access control and video surveillance, as well as branched computer networks and automation systems for production processes. These devices also increase fire safety, the reliability of power grids and the noise immunity. The desire to reduce the cost of the tray designs, increase their insulating qualities, reliability and environmental friendliness prioritizes the task of their manufacturing. The theoretical analysis of the bending process of a thin plate proved that the required cylindrical deflection of the plate can be achieved by varying the geometric characteristics of the plates (width, length and thickness). If a change in these parameters is not stipulated for the manufacturing process, then to obtain the adjusted shape change it is necessary to change the mechanical characteristics of the metal workpiece, including the yield point and Young's modulus. It will require either completely substituting the workpiece material or providing it heat treatment. The plate width decisively influences the amount of bending, since its value being in the second degree is included into the formula. Thus, to improve the production of trays for electrical networks by bending sheet blanks, it is recommended to choose at the correct ratio between the width and length of the workpiece. Under other unchanged conditions as to the material and thickness of the original workpiece, the plate length and width varying results in a change of the deflection magnitude in the center of the finished product. Applying this method for manufacturing the curved plates as a structural element of electric trays, we can reduce their technological cost and electricity consumption with only using the lower power press equipment.