EoW July 2007

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EuroWire – July 2007 52
english technology news
By helping cable products meet their
technical specifications, Cropico precision
measurement instrumentation also en-
sures that valuable copper raw material
is used efficiently.
The in-line installation of Cropico D05000
microhmmeters as part of copper cable
production facilities enables highly
accurate low resistance measurements
to be taken to ensure that products meet
relevant technical performance standards.
Installation of the D05000 in-line as part
of the production process also eliminates
waste material by cutting off cable
samples and scrapping the offcuts.
By constantly monitoring the resistance
value of the cable, the system also ensures
the cost effective use of copper raw
material in the manufacturing process.
Given the relatively high price of copper,
this factor is a significant consideration in
the cable manufacturing process.
All cable products are designed and
manufactured to close electro-technical
tolerances in keepingwith the requirements
of a host of international product and
performance standards.
The cable’s resistance value is critical in this
respect - if resistance is too high, then the
current carrying capability of the cable is
reduced. Since cable resistance reduces as
the diameter is increased, it is important
that the specified resistance per metre
is achieved in relation to the optimum
diameter of the cable.
Being too generous with the cable diameter
means more copper is being used than
necessary. As copper is themain contributor
to the cost of a cable, for maximum
manufacturing cost efficiency it is crucial
that the required resistance is achieved with
the minimum cable diameter.
The D05000 uses true four-wire Kelvin
resistance measurement technology
to eliminate lead resistance errors. This
system, alongside auto averaging of
test current and automatic temperature
compensation, ensures the highly
accurate measurement of resistance in the
cable during the manufacturing process.
In typical manufacturing environments,
the Cropico D05000 is linked to a specialist
clamp which holds a standard 1m length
of cable or wire in place as the copper
strands passes along the bobbin extruder.
The clamp incorporates separate current
and potential measurement connections,
which are attached to the cable for
resistance measurements to be made.
There are three cable models in the
Cropico range and these offer the ability
to accurately clamp and measure cable
up to 1,000mm 2. There is a model that
has an integrated water bath which will
automatically bring the cable under test
to a specific temperature.
Programmable current levels and the
selection of different test speeds gives
the Cropico tester flexibility to accurately
measure the resistance values of
different cable products. These include
single end and plain soft wires through
to bunched, stranded and large
diameter rope type conductors. Accurate
and reliable in-line cable resistance
measurements taken in this way enable
cable manufacturers to maintain optimum
operating efficiencies in terms of raw
copper material used. There are four
models in the D05000 series.
Cropico Ltd – UK
Fax: +44 191 586 0227
Email:
Website :
Precision increasing efficiency