Patent ID: 7268509

Claim:
An electric tool device, the device comprising: an electromotor, said electromotor being one of asynchronous or brush-less synchronous; a motor control means, said motor control means having computer control; a frequency converter which can be controlled by said motor control means for applying a drive voltage to said motor; and a current detector which detects a motor current and which communicates with said motor control means, wherein said motor control means is designed such that, in a first phase of motor operation at motor currents of up to a limit current I (limit) , the voltage applied to said motor and the frequency of the motor current are kept constant and, in a second phase of motor operation at loads above that load at which the motor current reaches the limit current I (limit) , the voltage applied to said motor is kept constant and the frequency of the motor current is reduced to such an extent that the motor current is kept at a constant value.