Motor overload detection circuit for hand-tool - compares current and voltage values obtained from current flux angle and motor revs

摘要

The circuit monitors the current flux angle and the motor revs, each of which is integrated and the integrated signals are used to obtain a voltage or current value, the 2 obtained values compared. Pref. a voltage obtained from the current flux angle is added to a reference voltage for determining the response threshold. The motor is pref. disconnected automatically when the difference between the 2 compared values is above a given difference value. ADVANTAGE - Has improved safety.