Calibrating and Verifying TIG / MIG Outputs

We calibrate our resistance welders to 200,000 amps. There are a few ways to do it and I won't go into detail on each one. You might consider using an instrument shunt which is simply a precision resistor that you would probably connect from the welder ground lead to ground. The weld current is the voltage measured across the shunt divided by the resistance of the shunt in ohms. Another method is to use a toroidal pick-up (sometimes called a Rogowski coil). They are used with a calibrated electronic integrator to read current. These coils have no iron in them and therefore can not saturate. You can also use a current transformer that has an iron core, but need to specify it properly so that it doesn't saturate. There are also hall generator current measuring devices, but I don't have much experience with them.

See the other post by you:

http://cr4.globalspec.com/thread/47414/Measure-TI-MIG-Power-Output?frmtrk=CR4digest