Rogowski coil with low permeability core
A Rogowski coil includes a magnetic core and a winding. The magnetic core includes an encircling body. The winding includes a conductive wire. The winding is disposed in a generally helical coil about the core body.
1. A Rogowski coil comprising:
a magnetic core having a relative permeability greater than one and less than twenty and including an encircling body that is structured to encircle a conductor that carries current at a frequency;
a winding including a conductive wire that is structured to generate an output whose amplitude is proportional to the frequency according to equation: N*μr*μ0*A/l*2*π*f*I, where N=number of turns, μr=relative permeability, μ0=permeability of free space, A=cross sectional area of the core, l=average circumference of the core, f=the frequency of the current in the conductor, and I=the applied current in the conductor;
said winding disposed in a generally helical coil about said core body; and
wherein said core body is a magnetic core body which, prior to magnetic saturation, has a transfer impedance of between about 1 mV/A and 20 mV/A at about 60 Hz and is structured to cause the Rogowski coil to produce a detectable voltage.
2. The Rogowski coil of claim 1 wherein said core body has a transfer impedance of about 10 mV/A.
3. The Rogowski coil of claim 1 wherein said core body includes Carbonyl-Iron.
4. The Rogowski coil of claim 1 wherein said body is structured to generate a non-amplified signal when exposed to a current.
5. A current sensor assembly comprising:
an output assembly;
a Rogowski coil including a magnetic core and a winding, the magnetic core having a relative permeability greater than one and less than twenty and, prior to magnetic saturation, having a transfer impedance of between about 1 mV/A and 20 mV/A at about 60 Hz and being structured to cause the Rogowski coil to produce a detectable voltage;
said magnetic core including an encircling body that is structured to encircle a conductor that carries current at a frequency;
said winding including a conductive wire that is structured to generate an output whose amplitude is proportional to the frequency according to equation: N*μr*μ0*A/l*2*π*f*I, where N=number of turns, μr=relative permeability, μ0=permeability of free space, A=cross sectional area of the core, l=average circumference of the core, f=the frequency of the current in the conductor, and I=the applied current in the conductor; and
said winding disposed in a generally helical coil about said core body.
6. The current sensor assembly of claim 5 wherein said core body is a magnetic core body.
7. The current sensor assembly of claim 5 wherein said core body has a transfer impedance of about 10 mV/A.
8. The current sensor assembly of claim 6 wherein said core body includes Carbonyl-Iron.
9. The current sensor assembly of claim 5 wherein said body is structured to generate an amplified signal when exposed to a current.
10. The current sensor assembly of claim 5 wherein said output assembly does not include an amplifier.
11. The current sensor assembly of claim 6 wherein said output assembly includes a saturation module.