Thomas Pikkemaat Interview on Servo and Feedback Cables with UL Approval up to 90°C
HELUKABEL is the first European manufacturer to entirely upgrade its TOPSERV and TOPGEBER product portfolio to 90°C UL styles. What are the benefits of higher heat resistance?
Thomas Pikkemaat: For many years, 80°C UL styles have been the market norm. Very few drive technology manufacturers currently offer servo and feedback cables with a 90°C UL style specification. From a technical perspective though, there are good reasons for doing this. In motor environments, temperatures frequently exceed 80°C. Take motor terminal boxes, for example, where conductors are often exposed to even higher temperatures.
What materials does HELUKABEL use for the jacket and conductor insulation?
Pikkemaat: We use PVC and PUR for the jacket. Polyurethane (PUR) is a thermoplastic elastomer with major benefits, particularly in drag chain applications where continuous flexing and high abrasion resistance are paramount. The higher heat resistance are a primary result of technical improvements in conductor insulation materials though. These days, we use polypropylene (PP) materials with heat resistance of up to 110°C. This thermoplastic not only has long-term temperature stability, it also has a very low dielectric constant. This makes PP an excellent insulation material.
You talk about improvements. Which materials did you previously use?
Pikkemaat: Until about 2009, polyester (TPE-E) was considered the best-in-class for drag chain servo cables. Its outstanding mechanical properties and high heat resistance made it a winner. However, TPE-E has two serious drawbacks. First, moisture, particularly at high temperatures, damages the hydrolytically sensitive plastic. Second, and this is critical, its high dielectric constant leads to high capacitance values that can cause problems over longer distances.
When did HELUKABEL start using polypropylene (PP) as the conductor material and what experiences have you had with it?
Pikkemaat: We’ve been using polypropylene since 2005. In the beginning, we dealt with the lower heat resistance because the available materials and technical understanding of at the time limited the temperature was simply limited to 80°C. The major benefits of its electrical properties continued to impress and this motivated us to look for ways to improve its heat resistance. As already mentioned, today we use special PP materials that can be optimally processed and are heat-resistant up to 110°C, thanks to further developments in the field of plastics and enhanced manufacturing methods.
Does this also apply to continuous use in machine tools, for example?
Pikkemaat: A good question. Obviously, heat resistance has to be measured in the right context i.e. time. For this reason, we subjected the new servo and feedback cables to months of testing in our high-tech laboratory in Windsbach. As a result of such strenuous and lengthy test, HELUKABEL can confirm conductor insulation heat resistance of 90°C for over 30,000 hours.
How was certification achieved by HELUKABEL?
Pikkemaat: We are the first manufacturer in Europe to entirely upgrade its servo and feedback cable assortment to 90°C UL styles. The necessary UL styles were created especially for HELUKABEL in partnership with UL and apply to all HELUKABEL Group manufacturing facilities.
When will the new cables be available? Will this change anything for HELUKABEL customers?
Pikkemaat: Our TOPSERV and TOPGEBER assortment will be available in 90°C UL styles starting in November. The upgrade will be seamless and products will maintain the same part number. As HELUKABEL has been using these heat-resistant materials for many years, the cables are technically unchanged except for the jacket marking, of course.