Magnetic slot wedges reduce starting current, improve cos phi and load current, and lead to reduced iron loss (core loss). Typical reduction of iron loss is in the range of some kW depending on the type of machine. This means a corresponding value of some thousand Euros, when calculating the machine prize. So it is obvious that additional costs for high performance slot wedges clearly pay off. Conventional slot wedges are that weak that they often are not fulfilling the mechanical needs so that some companies are not using magnetic wedges any more.