the study of current or voltage transformers ancillary facilities for automatic determination of the betragsfehlers and fehlwinkels an electricity or spannungswandlers

摘要

To ensure completely automatic determination and indication of the current and voltage errors or, respectively, the phase displacement angles in three error range steps without using conversion factors, an adjustable error-compensated current transformer (T5) is provided, the secondary winding (WF) of which can be switched in decade steps. A reference voltage @ derived from a reference current transformer (T1) or reference voltage transformer excites a digital 90 DEG circuit and generates two squarewave voltages, one of which is in phase with the reference voltage @ and one of which is phase shifted by 90 DEG thereto. These squarewave voltages are used for driving two sequence hold amplifiers (S/H1, S/H2) which ensure that at the time of their application, the voltage error and the phase displacement angle are available as voltage value from the difference voltage @, which is also provided, and the reference voltage @, which are indicated on two mutually independent digital voltmeters (DV1, DV2) at a triggering rate of predetermined clock pulse sequence. IMAGE