Patent ID: 8884557

Claim:
A method for operating a mains-operated electric motor for a power tool with switches, wherein the method of functioning of the switches is monitored for operational reliability with an electronic controller, comprising: arranging a first switch in a first mains connection line that is connected to a first side of the electric motor; arranging a second switch in a second mains connection line connected to a second side of the electric motor; and connecting the first and the second switches to the electronic controller by means of control lines; wherein in a first step (i) the first switch is activated and the second switch is deactivated by the electronic controller, (ii) an operating parameter of the electric motor is subsequently detected and is compared with a predefined value, and (iii) a malfunction of the switches is detected by the electronic controller if the detected operating parameter deviates from the predefined value, wherein in a second step (i) the first switch is deactivated and the second switch is activated by the electronic controller, (ii) an operating parameter of the electric motor is subsequently detected and is compared with a predefined value, and (iii) a malfunction of the switches is detected by the electronic controller if the detected operating parameter deviates from the predefined value, and wherein: a first current monitoring device is connected in parallel with the first switch in the first connection line, a second current monitoring device is connected in parallel with the second switch in the second connection line, and the first and the second current monitoring devices are each connected to the electronic controller for the purpose of monitoring the switches and for detecting the operating parameter.