The paper refers to an electric machine (motor/generator) with an adjustable magnetic field, because its rotor has a special construction that allows the deformation of its elastic permanent magnets. The permanent magnets deform due to a clamping stroke parameter and in this way the flux density of the magnetic field as well as the width and length of the permanent magnets are variable. The variable magnetic field crosses the stator coils which are supplied by the voltages and due to a variable magnetic flux density, a higher torque will result even at lower values of the currents. As a result, a higher efficiency will be obtained due to the increase in mechanical power and the decrease in losses (e.g., Joule effect) in the stator windings. The presented electric machine is a synchronous machine with variable geometry, belonging to the category of permanent magnet machines. Specific to this machine is the fact that the rotor magnets are elastic, being made of ferritic compound rubber with neodimium magnets N45.