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Aug 04, 2023

360° Shielding With Cable Glands

Markus Häfliger presents a reliable, time-saving EMC cable gland for high-voltage EV applications AGRO AG , a connection and installation technology specialist, has expanded its portfolio of shielded

Markus Häfliger presents a reliable, time-saving EMC cable gland for high-voltage EV applications

AGRO AG, a connection and installation technology specialist, has expanded its portfolio of shielded EMC cable glands, adding an all-new version for electrically powered industrial vehicles and mobile machinery. The EVolution EMC cable gland for high-voltage applications features a high current-carrying capacity and effective 360° shielding. The entire product design is tailored to the specific requirements of vehicle and component manufacturers and cable assemblers. Evolution EMC combines the advantages of “pluggable” connections with those of cable glands.

The new cable gland system reduces assembly times in electric vehicle (EV) production lines since Evolution EMC cable connections are as easy to handle as pluggable connections. The cables are assembled in just a few steps: the cable lug is fed through the cable gland, the contact sleeve is fastened, the sealing insert with anti-twist protection is inserted, and the compression nut is tightened all the way. This saves time-consuming, error-prone cable shielding work in the actual vehicle assembly line. In addition, repairs can be carried out quickly, reliably and effectively because the shielding is not compromised by repeated swapping of cables, and the slotted sealing insert can be replaced without separating the inner conductor from the cable gland system.

Cable glands for high-voltage electrical systems in machines and industrial vehicles must withstand high mechanical and thermal loads. If conventional connection technology is used, this can result in anything from inadequate EMC shielding and sealing to short circuits and, in the worst case, vehicle fires. High safety standards are required, especially for permanently installed electrical equipment with connections that are not included in maintenance routines and therefore must have a long service life. Such installations include AC converters, traction motors, PDUs and DC/DC converters – but also auxiliary drives, ancillary equipment such as air compressors, air conditioning compressors, coolers, steering pumps, fuel cells and any onboard charging infrastructure.

The conductors between converters and traction motors, especially, must provide reliable EMC shielding as well as a high, low-impedance current-carrying capacity and dissipation while ensuring minimal heating. EMC shielding quality is proven by measuring the transfer impedance – the lower the delta of the transfer impedance, the higher the EMC shielding effectiveness; standard requirements are < 2.5 mΩ/m at 2 MHz or < 5 mΩ/m at 30 MHz. Evolution EMC features significantly lower impedance values than most other solutions in the market and ensures protection even at extreme operating temperatures down to -40 °C and up to +140 °C. Connections between DC/DC converters and any ancillary equipment must also meet the highest standards due to the high switching frequencies, which require EMC shielding that ensures lifelong reliability. Overall, the entire vehicle high-voltage electrical system demands high protection levels because of frequent parasitic interference signals. All power and signal lines should be fully EMC-shielded.

Thanks to AGRO’s new axial crimping technology, the shield is connected to the cable sheath with a high retention force over a very short distance. This results in complete stiffening between shield contact and cable sheath, which complies with the German automotive industry standards LV 214 and LV 215:2017. The glands have been validated in 50 mating cycles with simultaneous testing of the shield contact resistance. The crimped 360° shielding ensures that the shield cannot be damaged after assembly and that the EMC shield contact position is permanently fixed in place. In this respect, as well as with its proven high shield pull-out strength, Evolution EMC exceeds the requirements of automotive manufacturers and offers significantly higher reliability and durability than conventional EMC cable glands with spring shielding. In the latter design, with a coupled sealing and shielding contact solution, the indirect mechanical pressure of the sealing insert on the shielding contact can lead to a loss of shielding attenuation due to different ambient temperatures and thus impair the operational safety of the entire vehicle.

The Evolution EMC cable gland, newly developed by AGRO, is designed for protected feed-through of high-voltage cables with braided copper shields and cross-sections from 16 mm² to 120 mm², as well as multi-core cables with smaller cross-sections. The cable glands, which are available with short or long connection threads in sizes M20 to M32, boast current-carrying capacities up to 200 A, depending on the thread size, and minimal heating. The shielding effectiveness is at least 86 dB in the 100 kHz to 300 MHz frequency range, ensuring reliable protection even against interference caused by high switching frequencies of DC/DC converters and AC converters. Evolution EMC is approved for an extended temperature range of -40 °C to +140 °C and features an IP68 or IP6K9K degree of protection. The alloy of the metal components consists of lead-free, RoHS-compliant brass with mechanical properties, corrosion resistance and electromagnetic compatibility compliant with current requirements according to IEC EN 62444 and UL 514B. The range of accessories includes dust caps, locking screws, EMC counter nuts for mounting on thin or painted sheets, as well as anti-kink nozzles.

Markus Häfliger is the innovation driver at AGRO AG