A method is provided for switching on and switching off an n-phase electric machine in a motor vehicle. The n-phase electric machine includes a rotor with a rotor winding, and a stator with an n-phase stator winding. An excitation current may be applied to the rotor, and an n-phase phase voltage may be applied to the stator. The excitation current is switched on or off, a parameter which influences a synchronous generated internal voltage is determined, and the phase voltage is switched on or off when the parameter which influences the synchronous generated internal voltage reaches a certain threshold value.