Speedage punched grid resistors consist of grids punched from corrosion resisting nickel chromium alloy sheet steels. The inherent strength of the steel itself is very high and owing to the pressed and rein-forced construction the rigidity of the grid is even higher. Punched steel grids are completely immune to shock and vibration. These function reliably under the worst operating conditions and are particularly suited for steel mill duty. They are comparatively lightweight for a given rating and are mounting dimensions. The series connection between adjacent grid is not through pressure contact via tie rod nuts but by means of suitable individual bolted connection copper jumpers. This completely eliminates any stress on the tie rod and insulators, which might result in damage during cycles of heating and cooling. When subject to severe unforeseen overloads of moderate duration these grids may become red hot but undergo no damage whatsoever and retain their shape after overload disappears.
