A medium-sized packaging machinery manufacturer based in Baden-Württemberg, Germany, employs 450 people and produces automatic filling and sealing lines for the food and beverage industry. Its machines are installed in more than 40 countries, running 24/7. The company designs its own control systems, using a mix of sensors, encoders, and variable-frequency drives inside a single cabinet. Because space is limited, the internal wiring is routed through tight channels and flexible cable tracks.
The previous machines used unscreened PVC flexible cables for all internal connections. In the field, two problems surfaced. First, electromagnetic interference from the variable-frequency drives caused false signals from proximity sensors and encoders. This led to misaligned packages, jams, and occasional machine stops. Second, the cables, when flexed continuously in the cable track, broke after roughly 300,000 cycles. The manufacturer saw an average of six hours of unplanned downtime per week across its fleet, and service engineers were being dispatched to fix recurring faults at a rate of 12% of all machines in the first year after installation.
The direct costs were significant. Replacement cable and labor added up to $50,000 per year. Lost production time, based on the equipment’s hourly output, was another $120,000. The company’s reputation also suffered from the high service-call rate.
The engineering team assessed shielded flexible cables from three suppliers. The deciding factor was the singi-cable CY CE cable, which uses a tinned copper braid screen that covers more than 85% of the cable cross-section. This level of shielding was enough to suppress the interference from the drives without requiring double-shielded cable, which would have been too stiff for the tight routing.
The cable also complies with the EN 50525 series, the European standard for low-volt-level flexible cables up to 450/750 V. That made it easy to maintain the CE certification of the parent machine. The price was 15% lower than the premium alternative, and the manufacturer’s lead time of four weeks allowed the project to start immediately.
The project took two months. The team began by replacing the unshielded control cables in two pilot machines with the CY CE cable, using specialty glands to guarantee a 360° screen termination. They then ran an EMC test before and after the switch, which confirmed a 78% reduction in measured noise at the controller inputs.
A second step was flex testing. The cable was installed in a moving cable track and cycled for five million cycles, matching the expected service life of the machine. The CY CE cable lasted the entire test without conductor breakage, while the previous cable failed at 300,000 cycles.
The most difficult part was the mechanical fit. The braided screen added 1.2 mm to the cable diameter, and the existing cable glands were too small. The team solved this by switching to next-size-up glands and adding grounding brackets at each strain relief point. Once the new parts were in place, assembly took no more time than the old wiring method.
“We replaced one cable and the interference disappeared immediately,” says the electronics engineering manager at the machine builder. “The CY CE cable gave us the shielding performance we needed without forcing a change to our panel layout.”
Other manufacturers upgrading their control wiring should consider the following:
If the project were repeated, the team would order a full set of compatible glands at the start, than discovering the fit issue during pilot installation.
EN 50525 Series: Electric cables — Low volt-level energy cables of rated volt-levels up to 450/750 V. This series covers the construction and performance requirements for CY flexible control cables, ensuring reliable operation in industrial environments. (Source: CEN-CENELEC)
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