Device having a variable-speed motor

A motor control device which comprises a motor having a coil arrangement and whose speed can be controlled by energization and deenergization of the coil arrangement in a pulsating fashion, and

• which includes a circuit for powering the motor, and the circuit comprises;
• two terminal means arranged to receive a d.c. supply voltage in operation, one single switching means connected in series with the motor, which switching means serves for the connection and disconnection of the motor coil arrangement to and from the d.c. supply voltage in a pulsating fashion for the purpose of controlling the speed of the motor, a control pulse generator adapted to generate and supply a control pulse sequence to a control electrode of the switching means which serves for the connection and disconnection of the coil arrangement, wherein the one switching means also serves for the energization and deenergization of the coil arrangement and produces turn-off voltage transients on a coil terminal of the coil arrangement, wherein the control pulse sequence applied to the control electrode of the single switching means also serves for the energization and deenergization of the coil arrangement, voltage boosting means which receives the turn-off voltage transients and which is adapted to generate a d.c. control voltage in dependence on the turn-off voltage transients and which applies the generated d.c. control voltage to the switching means, which serves for the connection and disconnection of the coil arrangement, wherein the d.c. control voltage from the voltage boosting means and the control pulse sequence from the control pulse generator can be applied to said control electrode, and the connection and disconnection of the coil arrangement and the energization and deenergization of said coil arrangement are identical.