FIELD: welding; checking of seam welding by measuring welding voltage. SUBSTANCE: with two seam heads used in welding, voltage is measured on two wire electrodes, on seam heads or their supports. Value of welding voltage is determined wear or contamination of seam heads is judged by difference in welding voltage. Welding voltage measuring device has voltage pickups with sliding contacts. Pickups are installed on wire electrodes, and on seam heads or their supports. Outputs of all pickups are connected to welding voltage control unit. Sliding contacts can be installed stationary, or can be spring-loaded. EFFECT: enlarged operating capabilities. 4 cl, 1 dwg
