Method for operating an electrical treatment device, wherein the treatment device has: - a user-operable operating switch, a motor electronics system having a motor control and an electric drive motor, - wherein the operating switch is electrically connected to a drive voltage source on the input side and to the motor electronics system on the output side, wherein the operating switch is designed to produce an electrical connection between the drive voltage source and the motor electronics system in a closed switching state (closed), and to disconnect it in an open switching state (on), wherein the operating switch is a disconnecting switch, and - wherein the motor electronics system is electrically connected to the electric drive motor on the output side by means of the motor control, wherein the method includes the steps: a) monitoring whether an input voltage (Uin) at the motor electronics system meets a closed criterion (ck) or an open criterion (ok), wherein the closed criterion (ck) is characteristic of the closed switching state (closed) of the operating switch, and wherein the open criterion (ok) is characteristic of the open switching state (open) of the operating switch, and b) if the open criterion (ok) is met, operating the motor control in a state (SZ, IZ) from an open state set, wherein the open state set includes a voltage control state for limiting an increase in the input voltage (Uin) caused by the running-down electric drive motor, - wherein by the use of the motor control as a step-up converter and the use of an induced output voltage (Uout) of the running-down electric drive motor the input voltage (Uin) is maintained at a voltage value. - a user-operable operating switch, a motor electronics system having a motor control and an electric drive motor, - wherein the operating switch is electrically connected to a drive voltage source on the input side and to the motor electronics system on the output side, wherein the operating switch is designed to produce an electrical connection between the drive voltage source and the motor electronics system in a closed switching state (closed), and to disconnect it in an open switching state (on), wherein the operating switch is a disconnecting switch, and - wherein the motor electronics system is electrically connected to the electric drive motor on the output side by means of the motor control, a) monitoring whether an input voltage (Uin) at the motor electronics system meets a closed criterion (ck) or an open criterion (ok), wherein the closed criterion (ck) is characteristic of the closed switching state (closed) of the operating switch, and wherein the open criterion (ok) is characteristic of the open switching state (open) of the operating switch, and b) if the open criterion (ok) is met, operating the motor control in a state (SZ, IZ) from an open state set, wherein the open state set includes a voltage control state for limiting an increase in the input voltage (Uin) caused by the running-down electric drive motor, - wherein by the use of the motor control as a step-up converter and the use of an induced output voltage (Uout) of the running-down electric drive motor the input voltage (Uin) is maintained at a voltage value.