Preventing cable failures in cable carriers

Too often, cable carriers that have been carefully designed to meet an application's mechanical variables fail when cable behavior is not considered. Carriersthat are filled beyond 60% of total capacity,or where the cable manufacturer's speci-fications are not factored into the minimum bending radius, regularly result in conduc-tor breakage or twisting, or "corkscrewing," of cables.

Selecting a carrier system that can be easily customized to precise width specifications will maximize cavity opportunity while minimizing applications space interference. Additionally, cables with disparate outer diameters or jacket materials should be isolated from each other to prevent them from rubbing together or twisting. All cables should be clamped at both fixed and driven ends of the carrier.

The installation of vertical dividers is a simple, cost effective method of isolating cables. In applications where space is critical, a combination of vertical and horizontal dividers will create multiple compartments for isolation. Carriers can also be designed with aluminum or plastic interiors that have been custom-bored for a specific layout. These systems provide maximum cable protection, allowing the cables to follow the neutral axis of the carrier.

To contact a KabelSchlepp applications engineer, call 414-354-1994 or fax 414-354-1900.

Oscilloscope clamp: Measurement for all categories

Didier Piaud, R&D Manager Chauvin Arnoux, Paris, France

While the current clamp is an ideal detector for measuring a current without interrupting a circuit, this is not its only function. When it is particularly necessary to ensure the safety of users and to protect their equipment, the current clamp is equally effective as an isolated sensor. It can even enable electrical engineers to make measurements in another more difficult installation category of an industrial type.

A current clamp can be used to form connections according to European standards, particularly with respect to the new Low Voltage Directive. This specifies the conditions for using measuring instruments according to their electrical environment category (the category of installation or overvoltage).

For example, in a workshop containing motors connecting to the mains, the room is classed in Category III (Electrical Engineering). To display a signal from one of these motors, it is necessary for the oscilloscope to also be Category III. The ad-hoc solution is to use a current clamp, such as the E3N clamp. The clamp provides the whole measuring system with the characteristics to meet safety regulations.

By using a clamp, existing instruments can be adapted to meet new safety standards. The total cost of this is much lower than the cost of buying instruments with differential inputs.

To speak with a Chauvin Arnoux applications engineer, call +33 1 44 85 44 86.