| 摘要 |
A circuit arrangement 10 for an electric protective device comprises a first electric line 12, an electromagnetic isolating device 16 of a coil and plunger type, a switching device T1, a voltage divider 22 and a control device 18. The control device 18 detects the presence of a fault current and/or an arc in/on the electric line 12 and generates a trigger signal trig that activates the switching device T1. Once activated, the switching device T1, which may be a thyristor, allows a voltage U to be applied to the electromagnetic isolating device 16 and thereby isolates the electric line 12. The control device 18 is embodied to detect a zero crossing of the electric voltage U and to generate a trigger signal trig after a specified time or interval of time after the detected zero crossing, or at a particular voltage phase, so that the overall energy absorbed by the coil is controlled. The limits of a time interval may be calculated from static and/or dynamic force measurements on the electromagnetic isolating device 16 or an operating temperature of the electromagnetic isolating device 16. |
