| 摘要 |
The invention relates to a device for representing and displaying the coil temperature of an electrical power transformer and to an electrical circuit suitable therefor. The invention is based on the general concept of using the CT-signal current not only for supplying the heating resistor of a sensor, for example, but also for decoupling energy from the CT-signal current by transformation via an electronic circuit according to the invention in order to supply energy to the connected measurement devices, so that a separate energy source can thus be ultimately omitted. According to the invention, the primary coil of a transformer, hereinafter referred to as removal transformer, is inserted into the CT-signal current and the voltage sloping via the primary coil and secondary coil of the removal transformer is limited in that a triac triggered by two diodes connected in parallel short-circuits as soon as the corresponding half-cycle reaches a threshold value and does not open again until the next current zero-crossing of the CT-signal current. |
