Factor to Calculate Exact Current for Supply Power of Welding Machine

The British Standards Institution can do this though there is a fee to pay for publications. The document needed is British Standard 7671. On-line ordering using a credit or debit card is tickety-boo.

If in doubt, consult a qualified Electrician locally.

First, select which of the given input voltages you will be using.

Dear Friends

Input voltages will be use for welding machine is 380 voltages ( AC three phase).

Tornado has given you enough rope to hang yourself.

You'd better hope that no one asks you to justify your answer.

Or, worse yet, challenges you to show your work.

Or, wants your advice about another electrical calculation.

If they do, you're TOAST!

What about using three clamp on amp meters on the feed wires for the three phase? Not most accurate but it should answer your question or lead you in the right direction. Calibrate the three to read the same current accurately by clamping them all on the same cable along with a known correct meter.

Use one meter for the single phase.

If you want the parameters for the secondary use a clamp on amp meter (AC or DC depending upon the welder setting) and a volt meter across it. Have a good welder strike an arc and maintain a consistent arc. Read the meters.

Good Luck, Old Salt

Dear oldsalt

My understanding from the OP is " how to calculate the incoming supply cable size and mcc rating. This involves calculations as per applicable standards.

What I understand from your post is to measure the current - which means the welding machine is working and the current to be measured. The incoming supply or mcc may be oversized/undersized installation.

After measuring the current, it may call for replacing the cable or mcc or both if under-sized which is a trial and error basis. Am I right.?

DHAYANANDHAN.S