ISO 22829:2007 is applicable to transformer-rectifier units as used in electric resistance welding machines operating from a power supply with a frequency of 1 000 Hz, and of a rated value of the input voltage equal to or higher than 500 V. These transformer-rectifier units are primarily used in welding guns with an integrated transformer.
For these transformer units, ISO 22829:2007 supplements the requirements given in ISO 5826 and ISO 10656, which remain applicable except where amended by ISO 22829:2007.