hi,friends.i got some trouble in automatic multi-wire saw welding.during the welding process,all wires'  arc voltage drop down suddenly,after ajusting to the set value,it rise up.there are two sets of equipment,the same type and same arrangement,the other doesn't have this phenomenon.
i think there maybe something wrong on voltage feedback,but i am not sure about it,and have no idea on how to find out the reason.
could you please give me some advice ?thanks

forseti.