The ISA range of Inverter power supplies provides the highest level of control available today in large scale resistance spot welding. The ISA-500CR, ISA-1000CR, ISA-2000CR and ISA-4000CR are intelligently packaged in “NEMA” style enclosures and are designed to deliver robust performance in the harshest of production environments. The ISA models can deliver 500, 1000, 2000 and 4000 amps of primary welding current, respectively.