Tesmec esmecMag
09#2012 July 2nd
JOURNAL OF MARKETING INFORMATION
Mr. Alberto Oscar Technical director of Stringing Equipment Division, describes Tesmec Bull-Wheel Lining
BULL-WHEEL LINING AND CONDUCTOR LOADING Tesmec researched and experimented several different materials for bull-wheel lining during 60 years of history. The research focus was and s ll is the best compromise between the fric on coefficient of the bull-wheel grooves and the conductors and the stress created on the surface and inside the conductors. Tesmec have designed and patented two unique materials, nylatron and special treated steel, used as the primary lining of Tensioner and Puller/Tensioner bullwheels grooves. Tesmec Tensioner and Puller/Tensioner bull-wheels have therefore a hard surface which guarantee a very low fric on coefficient between the conductor and bull-wheels but enough to guarantee a limited back pull on the reel stands. By these solu ons the conductors lean on the bo om of the grooves and do not climb the grooves sides.
Other manufacturers bull-wheel linings are o en made by urethane material, which is much so er and therefore there is the possibility that the conductors climb the groove and consequently suffer of torsional stress bringing the Bird Caging phenomena. Most of Tesmec machines are designed to simplify the loading of the conductors on the bull-wheel; this is obtained by having a central beam with the couples of the bull-wheels at the two side of it. The conductors can be wrapped across the bull-wheel both from le to right and from right to le independently from the conductors forma on due to the very low fric on coefficient. It is important to note that Tesmec have produced more than 8000 machine, more than 50% of the en re global market. Tesmec machines proved to be the most efficient, safe and friendly solu on in any stringing project.
Tesmec esmecMag 09#2012 LOW FRICTION, DURABLE SOLUTION Tesmec tensioners and puller-tensioners grooves come with the op on of: •
Nylon - nylatron sectors
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Steel with thermo-chemical treatment
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Benefits are: •
Hard surface with no influence on the conductor because the contact pressure between conductor and grooves surface is lower than the internal pressure between elementary wires of the conductor (see elementary conductor wires in pink color)
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Low fric on = self-alignment of the conductor on the bo om of the groove
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No influence related to the right-hand or le -hand forma on of the conductor = machine simple to use and faster conductor loading procedure
Photo 1 Nylon - nylatron grooves details
Aluminium Steel
ATTENTION ! So lining bull-wheels surface generates high fric on, so even if it reduces the number of the grooves, it doesn’t allow the self-alignment of the conductor on the bo om of the groove, with possibility of damaging the conductor (bird-caging)
SOFT BULL-WHEEL GROOVES = CONDUCTORS STRESS
Tesmec esmecMag 09#2012 2
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5 Photo 2 Big conductors on nylon - nylatron grooves Photo 3 Nylon - nylatron grooves Photo 4 Steel with thermochemical treatment Photo 5 Central beam machine with steel grooves, top solu on.
Tesmec esmecMag 09#2012
TESMEC S.p.A - Headquarters via Zanica, 17/O - 24050 Grassobbio (BG) - Italy Tel. +39.035.423 2911 - Fax +39.035.4522444 Management and Administra on Fax +39.035.4522445 Stringing Equipment Division - Fax +39.035.335664 Trencher Division www.tesmec.com - info@tesmec.it