Need to make adapter plug to go from big blue 400 to syncrowave 210

[DTerpwelding]

I have a big blue pro 400 on my welding rig and would like to run my syncrowave 210 off of it but the big blue has a 4 prong 240 outlet and the syncrowave has a 3 prong 240 plug how would I go about wiring up an adapter extension cord thanks

[Bushytails]

You'd connect the hots (X and Y) and ground from the 4-pin plug to the same pins on your 3-pin receptacle, and not use the neutral on the 4-pin plug.

[MAC702]

I have one I made hanging here. Get a NEMA 14-50P plug and a NEMA 6-50R receptacle or female connector. You only need a 3-wire cord (two hots and a ground) and you don't use the middle blade of the 4-prong. In fact, you don't even need to install it into the plug.

[DTerpwelding]

Thanks for the response every one