EoW November 2009

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EuroWire – November 2009 50
Power cables
Power cable marking
There are two types of colourless embossing suitable for medium to high voltage cables: raised and indented embossing. Raised
embossing uses an embossing wheel with engraved embossing dies, or ‘segments’, attached to it, that roll along the hot, soft cable
sheathing material immediately after extrusion, leaving a marking on the surface of the cable in the form of raised lettering. Indented
embossing is usually carried out on a cold cable surface using heated embossing wheels with raised engraving. Indented embossing
cannot achieve such high production speeds as raised embossing, as it involves the use of heated embossing dies that require the
transfer of heat to the cable sheathing material.
Many cable embossing machines can also
be used to mark up continuous lengths
(number of metres), and are therefore
equipped with embossing wheels with a
one-metre circumference. The embossing
wheel contains a counter – usually with
four or five digits – that increments with
each revolution of the marking wheel so as
to apply a consecutive metre reading to the
cable sheath. A reset mechanism makes it
possible to reset the metre counter quickly
and easily, for example when a new cable
reel is fitted to the winder.
The marking wheels of all standard KMS
Series cable embossing machines from
Medek & Schörner are fitted with a metre
counter with a manual reset and two
segment clips. In accordance with the
standard, these are used to apply marking
text to the cable sheath at distances of half
a metre.
The metre counters can also be pro-
vided with an electro-pneumatic reset
mechanism that can be synchronised with
the winder in such a way that it is reset
precisely where the cable end is cut. The accuracy of length marking depends on many factors including slippage between marking
wheel and cable surface, deformation of the cable during the embossing process and subsequent shrinkage of the cable. Medek &
Schörner offers auxiliary drive units that can compensate for slippage, or can be synchronised with great accuracy with a revolution
counter or any other type of transducer. This makes it possible to reduce measuring errors to less than 0.1%.
Some cable standards prescribe the embossing of cable sheaths on two sides, though no length marking may be required. For such
applications, Medek & Schörner offers the ICS series, which apply marking to the hot cable sheath immediately after the extruder
using embossing wheels with recessed engraving. Cooling the embossing wheels with water prevents them from sticking to the soft
insulation. These machines also offer a wide range of marking fonts using easily exchangeable embossing dies.
Medek & Schörner – Austria Fax: +43 1982 7296
Email: Website:
ICS embossing unit with concave, water-cooled embossing wheels for marking cables on two sides ▲ ▲
Queins & Co GmbH produces heavy-duty
stranding and cabling machines, and
a range of rigid, skip-type and tubular
stranders, planetary stranding and armour-
ing lines, drum twisting lines and bow
stranders for the production of medium
to extra-high voltage cables, offshore
and umbilical cables. Suitable capstans
and taping heads are also available, and
CTCmachines for continuously transposed
conductors.
Payoff and take-up stands capable of
carrying up to 300 tons drum weight, and
caterpillar capstans with up to 15 tons
pull can also be supplied.
Standard sizes for 800kg,
1,500kg or 2,000kg pull are
available from stock.
Also available are used
and reconditioned cable-
makingmachines, which can
be modernised and finish-
ed with new components
according to the customer’s
specifications.
Queins & Co – Germany
Fax: +49 2472 3014
Email:
Website:
Producing electrical cable
Special rotating belt caterpillar with a contact length of 4,900mm ▲ ▲