| 摘要 |
A circuit arrangement for enabling the magnetization and demagnetization of electromagnets operated by direct current utilising the self induction current produced in the coil of the electromagnet has two polarized capacitors (C1, C2) connected in parallel with the coil (L) of an electromagnet (M), the capacitors being series connected such that their like poles are connected to each other and a reverse direction diode (D1, D2) is connected in parallel with each capacitor (C1, C2). The magnetizing voltage charges one of the capacitors (C1) through diode (D1) so that it will not be damaged by the self induction voltage produced in the coil (L) of the electromagnet (M) after the magnetizing current has been cut off, the voltage being opposite to the polarity of the capacitor (C1). The electrical energy produced by self induction in the coil (L) of the electromagnet (M) after the magnetizing current has been cut off will become charged and levelled out into the capacitors (C1, C2), producing a low resistance to the self-induction voltage and thus causing strong demagnetizing current in the coil (L) of the electromagnet (M). In alternative circuits only one diode is used (Figs. 2, 3, not shown), and one or both of the capacitors may be a non-polarised capacitor. <IMAGE> |
