Pulp, Paper & Woodtech


Paper and wood are ubiquitous materials that surround us in our daily lives, appearing in products such as corrugated cardboard packaging and wooden-based kitchen cabinets. In the production process, wood is cut in sawmills, and paper pulp is processed in paper mills, both of which utilize adjustable individual electrical drives with rated power ranging from 100 kW up to 11 MW.

Working principle

In paper mills, pulp is obtained from wood through chemical processes, and the resulting paper pulp is then fed onto a rotating endless sieve in the headbox. The paper web is subsequently subjected to various rotating rolls and presses to remove excess water before being smoothed and rolled up in the drying section after passing through steam-heated drying cylinders.

Damaging effects

In paper mills, parasitic ground currents may flow via the motor bearings due to the presence of several independent variable frequency drives. This can lead to electrical erosion in the bearings, resulting in fluting on the motor bearing raceway after a few thousand hours of operation. Leakage currents can also cause unwanted triggering of security devices such as residual current devices or disturbances on sensor cables.

The Solution

To address these issues, our Blueferrite-Nanocrystalline cores can be easily mounted above the motor cables at the inverter output. These ring cores offer high impedance and high saturation current levels, reducing unwanted common-mode ground currents to a harmless level. By increasing bearing lifetime and preventing unwanted maintenance costs, our cores provide an effective solution to the challenges faced in paper mills.

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