Leakage current protection device

Abstract

A leakage current protection device with a single laminated magnetic core transformer that is formed by punch pressing an amorphous metal material, or a nanocrystalline soft metal material, in a high punch velocity press to form the ring laminations for the magnetic core. In a ground fault circuit interrupter, the single laminated magnetic core transformer serves as the input sensor for both the current imbalance detection circuitry and the low impedance ground fault protection circuitry.

1 . A leakage current protection device, comprising:
 a magnetic core including one or more amorphous metal laminates;   a first secondary winding coupled to the magnetic core, the first secondary winding having a first number of turns; and   a second secondary winding coupled to the magnetic core, the second secondary winding having a second number of turns,   wherein the magnetic core is configured to continuously sense both differential current levels and ground fault conditions.   
   
   
       2 . The leakage current protection device of  claim 1 , further comprising:
 an amplifier coupled to the first and second secondary windings; and   a contact control connected to the amplifier and a contact, the contact control configured to open the contact if a differential current level is above a threshold level and/or a ground fault impedance is below a threshold level.   
   
   
       3 . The leakage current protection device of  claim 1 , wherein the magnetic core comprises a plurality of nanocrystalline amorphous metal laminates. 
   
   
       4 . The leakage current protection device of  claim 3 , wherein the amorphous metal laminate has a thickness between approximately 17.78 μm and 25.4 μm. 
   
   
       5 . The leakage current protection device of  claim 3 , wherein the second secondary winding includes about 150 turns to about 300 turns. 
   
   
       7 . The leakage current protection device of  claim 3 , wherein the first secondary winding includes about 500 turns to about 2,000 turns. 
   
   
       8 . The leakage current protection device of  claim 2 , wherein the first secondary winding includes a parallel resistor for differential current sensing. 
   
   
       9 . The leakage current protection device of  claim 8 , wherein the second secondary winding has a parallel capacitance for ground fault detection. 
   
   
       10 . A leakage protection device comprising:
 a ring-shaped magnetic core including one or more amorphous metal laminates, defining an aperture through which a first primary winding and a second primary winding extend;   a first secondary winding coupled to the ring-shaped magnetic core, the first secondary winding configured to sense differential current levels in the first and second primary windings; and   a second secondary winding coupled to the ring-shaped magnetic core, the second secondary winding configured to detect a ground fault in the first and second primary windings.   
   
   
       11 . The leakage protection device of  claim 10 , wherein the magnetic core comprises a plurality of nanocrystalline amorphous metal laminates. 
   
   
       12 . The leakage current protection device of  claim 11 , wherein the amorphous metal laminates have a thickness between approximately 17.78 μm and 25.4 μm. 
   
   
       13 . The leakage current protection device of  claim 10 , wherein the second secondary winding includes about 150 turns to about 300 turns. 
   
   
       14 . The leakage current protection device of  claim 10 , wherein the first secondary winding includes about 500 turns to about 2,000 turns. 
   
   
       15 . The leakage current protection device of  claim 10 , further comprising:
 an amplifier coupled to the first secondary winding and the second secondary winding.   
   
   
       16 . The leakage current protection device of  claim 10 , wherein the first secondary winding includes a parallel resistor for differential current sensing. 
   
   
       17 . The leakage current protection device of  claim 10 , wherein the second secondary winding has a parallel capacitance for ground fault detection.