Permanent magnets from rare earths play a central role in the field of electrical engineering. However, since more than 90% of the rare earths mined worldwide come from China and interim export restrictions have repeatedly led to high prices, efforts are being made to reduce the use of rare earths in electrical machines. This can be done in different ways. One possibility is hybrid excitation, in which a part of the permanent magnets in a machine is replaced by a current-carrying winding. In this work, different topologies of hybrid-excited electrical machines are examined with regard to their suitability to vary the magnetic flux with the help of additional electrical excitation. All the topologies examined can be traced back to one form of the flux switching machine. This type of machine was selected because an additional field winding can be attached to the stator and slip rings can be omitted. In a series of finite element simulations, the effect of different magnetic materials on the flow controllability, as well as the dependence of relevant electrical quantities (harmonics of the voltage) on geometric parameters of the machines were examined. A topology was selected from the investigated machines, a prototype was built and the simulation results were verified using measurement technology.