Stator series resistors

When switching on three-phase synchronous squirrel-cage motors directly, large amounts of inrush currents flow, which can cause the nominal current to multiply.

Using three-phase stator series resistors, these inrush current peaks can be limited. A one-phase stator series resistor and a so-called squirrel-cage motor soft starter resistorcan in turn reduce the starting torque. This use is often implemented for heat pumps in the domestic energy sector, for example.