Patent ID: 8487570

Claim:
Method for operating an electric motor having a phase angle control with the following steps: applying an AC voltage to a series connection of the electric motor and a switching element comprising a triac, wherein said switching element connects through by applying an ignition signal and suppresses the flow of a current if the amount of current falls below a holding current; determining a time of a virtual zero crossing of a motor current that would flow if said switching element were connected through by: detecting a voltage jump across the switching element; and comparing the timing of the voltage jump to the timing of an ignition signal, wherein a first voltage jump that occurs at or near the timing of the ignition signal signifies a turning on of the switching element, and a second voltage jump signifying a turning off of the switching element approximates the virtual zero crossing of the motor current; and; turning on said switching element at an activation time that is dependent on the time of the virtual zero crossing of the motor current.