| 摘要 |
The circuit arrangement contains a measuring circuit (OP1, OP2) having a storage circuit (C1, R3, R4, R8) whose storage element (C1) is in each case charged, when motor overloads occur, by a value which is dependent on the current intensity and duration, and which is discharged again when there are no overload currents. The storage circuit (C1, R3, R4, R8) is dimensioned such that its charging time constant is less than its discharging time constant in order to achieve as good an approximation as possible of the charge state of the storage element to the motor (winding) temperature. The storage element (C1) is connected to a threshold-value monitoring circuit (OP2) which stops the drive motor (M), via a switching element (T) located in the motor supply circuit (L1 - L3) when a specific charge voltage on the storage element (C1) is exceeded. <IMAGE>
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