JF type grid


Resistor bank

JF grid bank assembly

Microelettrica Scientifica's resistors for traction are based on JF type grids. JF grids are manufactured in a totally automatic computer controlled processing plant. Coils of Ni-Cr steel strip, with different thickness and width, are fed into the plant where the strip is stamped, cut and welded.
The resistor grids are then assembled on stainless steel rods covered by an insulating material which is resistant to very high continuous temperatures. Further insulation over the tie rod is provided by special ceramic spacers. At both ends of the bank ceramic washers with a creepage distance of 70 mm are used to complete the insulation.
Simple mechanical constructional arrangements allow for expansion of the grids at high temperatures thus preventing dangerous distorsions.