| 摘要 |
The invention relates to a device (10) for taking a safety precaution in an electrical tool, said electrical tool comprising an electric motor (EM) with at least one field winding and an armature winding. The device (10) comprises the following features: a sensor unit (12) which is designed to generate a sensor signal (21) in accordance with a motor current (14) passing through the electric motor (EM), an armature voltage (16) via the armature winding, a voltage (18) via the field winding and/or a commutation frequency (20) in the armature winding; a unit (22) detecting a change of the sensor signal, which is designed to detect a temporal change of the sensor signal (21) and emit a corresponding modification signal (24) on the basis of the detected change; and a safety device (26) which is designed to take a safety precaution (28) in the electrical tool when a value of the modification signal (24) is exceeded or not met in relation to a threshold value.
|
