Contact Design for Air Break AC Motor Starters

The processes used to determine the contact design, force, weight, shape, and temperature rise for air break ac motor starters are explained. The contact force is shown as the function of the welding current. The contact weight is determined by contact erosion. The contact shape is shown as the function of the contact weight. The temperature rise is given as the functions of the cross section and current. The given data are based on measured values. A sample contact design shows the application of this material.