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Resulting from the constantly increasing number of electrical and electronic appliances in both commercial and private spheres and the ongoing process of standardisation in the field of electromagnetic compatibility, there is a growing consciousness regarding possible electromagnetic interference problems of appliances. In the case of resistance welding equipment, special attention is paid to the occurring electromagnetic emissions because of the high rated-power parameters and the intermittent operation of these devices. Different noise mitigation measures, considering the special characteristics of the generation and propagation of disturbances in the case of resistance welding inverters are discussed in this paper.

Resulting from the connection between the change rate of a magnetic field and the induced currents in an exposed human body, pulsating magnetic fields have to be evaluated analyzing the waveforms of the field or the field-generating current. Considering the specific output current waveforms of resistance welding installations in the paper appropriate procedures to determine the waveform-dependent exposure limits are explained by the example of a resistance welding inverter. Based on investigations of the field distribution the actual flux density values are compared to the ascertained exposure limits.

Nowadays simulation tools are widely used in the design process of power sources for arc and resistance welding. A modern inverter-type welding power source is a complex power electronic system, which is characterized by high switching frequency, fast dynamic response and a special load adapted process control. Although for an overall simulation on the system level simple semiconductor models may be sufficient, some relevant problems can only be solved on a circuit level simulation considering dynamic semiconductor models, driving circuits and parasitics. In this paper experiences with the practical parameterization and application of some recently introduced data sheet based models of diodes. MOSFETs and IGBT are described.

The droplet emission in a modified pulse arc process was investigated in relation to the DC random arc process. Nitride coatings were deposited on surfaces of stainless steel and of polished high speed steel. Ti, Cr and TiB (96:4 at%) were inserted in the deposition arrangement as target materials. The special melting points of these target materials makes a different behavior of the cathodic arc discharge possible. The deposited layers were analysed on the droplet number, droplet size and droplet shape. Furthermore the surface roughness was measured. The structure and the stoichiometry were tested. It was found that the modified pulse arc deposition reduces the droplet emission. By using the modified pulse arc process, the surface roughness of TiN decreases about 20% in comparison to DC mode deposited TiN layers. The modified pulse arc process has no influence on layer structure and layer composition.