Over the last few years, many new insulated type safety electrification systems have been developed. All of these systems provide a safe means for bringing power to hoists and bridge cranes.
The Enclosed Duct Type: Has two or more conductors inside a square metal track, or individual insulated bars of galvanized steel, copper, or aluminum. These bars are completely enclosed with an insulated shield which has a split on the front edge. A set of collector shoes on the passing crane or hoist equipment bears firmly against the electrification bar and virtually opens the insulated jacket which springs closed again as the equipment passes. This type of electrification can be used for straight or curved requirements.
To accommodate for icing and extreme climate problems, sheet metal covers can be placed over the bars for weather protection and high temperature jackets are available in most situations. The duct type systems are considerably more expensive, utilizing a multiple collector trolley riding inside the square duct. It is a sturdier system and generally offers good weather protection for outside installations. By far the most popular style of insulated system used by crane manufacturers is the individual insulated bar.