Magnetic shielding of power supply of electric glass oven

Abstract

In this paper the magnetic impact of cable supply distribution of an industrial electric oven is presented. Starting from the site survey up to the final mitigation solution, the paper show how to solve the problem and to reach the European Directive constraints regarding magnetic field exposure. The very high currents flowing in the supply cables generate high magnetic which overcome the worker limits. The main magnetic field component is at 50 Hz. The critical area is concentrated at the bottom of the oven which is not usually an area where workers are present. Only some workers dedicated to the maintenance fo the oven have to occasionally stay in the area below the oven. The need to protect such workers has pushed in the direction of finding a mitigation solution. The proposed and installed shielding is based on ferromagnetic material and so it works according the local magnetic flux deviation. The performances of the mitigation solution shows a very good results and the initial average value of 2500 mT is reduced to less then 1000 mT.