Patent ID: 7193428
Filing Date: 2007-03-20
Classification: G01R

Abstract:
1. A device for monitoring electric current in a power cable comprising: (a) a sensing transformer having a secondary winding electromagnetically coupled to said power cable and producing a voltage signal when a current is present in said power cable; (b) a voltage multiplier to amplify said voltage signal; (c) a switch having a first terminal and a second terminal, said switch responsive to said amplified voltage signal to enable conduction between said first and said second terminals and disable conduction between said first and second terminals when current is not present in said power cable; (d) a first Zener diode having a first forward bias; and (e) a second Zener diode having a second forward bias and connected in series with said first Zener diode with said second forward bias opposing said first forward bias, said first and said second Zener diodes connected in parallel with said secondary winding.