Mains connection of welding machines

Before connecting or setting up resistance welding machines, a number of boundary conditions must be checked or ensured. The most important parameters are the available mains short-circuit power and the conductor cross-sections for connecting the machine. In addition, the nominal frequency, the nominal primary voltage and the connected load are important parameters. The connected load in kVA is the power rating according to which the connection of the machine (the supply lines, the switchgear, etc.) is rated. The determining factors are the heating and the voltage drop (lead cross-section).

As a rule, the connected load is 0.6 times the short-circuit power. Furthermore, the values for duty cycle and clocking are important parameters for connecting the machines. With single-phase AC machines, it must also be taken into account that asymmetries can occur in the network. This problem does not apply to the medium-frequency systems that are mainly used today. Here, all three phases of the mains voltage are equally loaded. Important basic information on the mains connection of resistance welding machines can also be found in DVS Code of Practice 2918.

This is currently being revised by the DVS working group AG V 3.6 according to the latest findings and experience. Further information and advice is also available from the relevant mechanical engineering and welding technology companies.

You can also contact your Harms & Wende partner at any time for advice and assistance.