Dear Mr.Prahlad,

I guess you are working for some Welding Machine Manugfacturer. May I ask whom, as a matter of curiosity ?

By the way, I am aware of the problems your are facing since I have handled these machines. You can use the output busbar as shunt however, the result is neither consistent nor reliable. One accurate method used all over India is to use toroidal coil to measure the current on the secondary side. This is a high number of turns coil,very thin wire gauge, easily removable from the output busbar. The coil is to be wrapped on the output dc busbar and the coil gives millivolts as output voltage which needs to co-related with the current. Once done, this gives highly accurate & reliable readings. This method is being used by
M/s Miyachi Technos Corporation, Japan; manufacturers of welding controllers & weld current monitors.

Regards.

Mandar