| 摘要 |
For the purpose of detecting phase changes (sin .delta.) in an alternating-voltage mains, an apparatus is provided in which in each mainsphase a weakly attenuated oscillating circuit follows the mains-phase position after a considerable delay. Further, a multiplier is provided in each mains phase, to which are passed the output voltage from the relevant oscillating circuit and a voltage perpendicular to this voltage in the steady state. The phase-changes (sin .delta.) arising are taken off by passing the output voltages from the multipliers to an adding amplifier. |
