| 摘要 |
<p>A differential current protective switch, a DI switch, which operates with a cumulative current transformer and a triggering device in a secondary circuit on the secondary winding of the cumulative current transformer, the conductors to be protected by switch contacts being fitted in the primary circuit. The cumulative current transformer is to consist of a core material with the following features: the remanent inductance after excitation with H = 500 mA/cm, Br, is in the ratio Br/Bmax </= 0.5 to the inductance at H = 500 mA/cm, Bmax; the relative permeability mu r at small alternating swings of 4 mA/cm, mu 4: mu 4 >/= 30,000; the reversible permeability, i.e. the relative permeability on direct field swings with H = 250 mA/cm and superimposed minor alternating field swings, mu rev, is Sg(m)rev >/= 3000; the inductance with the a.c. field intensity, B, at a frequency of 50 Hz and an amplitude of 50 mA/cm is: B >/= 0.6 T.</p> |
