A method for the reduction of losses and improve the transmission of various holding to measuring value to the transmission member, as well as an apparatus for carrying out the method

摘要

At a measurement-value transformer for potential-isolated transfer of direct-current or direct-voltage signals by transformatorial transfer means (9) and with chopping means (Sa, Sb), which are connected in such a manner that an alternating-polarity induced flux is produced at the switching rate in the transfer means (9), in accordance with the alternating polarity of the magnetic field strength (H), it is proposed to reduce the losses, and thus to improve the transfer characteristic, by the following measures: control means (30) for activating the chopping means (Sa, Sb) are provided which comprise time delay means. These activate the chopping means (Sa, Sb) in such a manner that the switching-on edge of the current (I'2) causing one polarity of the induced flux is separated by a predeterminable time interval ( tau ) from the switching-off edge of the current (I'1) producing the other polarity. The reduction in losses is achieved by the reduction in the slope of the induced flux achieved by this means, in accordance with the reduced slope of the magnetic field (dH/dt) on polarity reversal, compared with a virtually delayless polarity reversal. IMAGE