i want information about the availability of shunt materials which are used for the measurement of high current(100KA, 4/10micro second wave shape) in impule applications.
measurement of d.c. currents of this magnatude (>25,000 amps ) are acomplished with a "transductor " circuit, two iron core coils with the d.c. current passing through the center. as the magnetic field of the conductor increases due to current, the iron in the coils becomes saturated and impedance goes down, current in the transductor circuit goes up.
this system is used in the electroplating industry.
I don't know the formulas for engineering a system from scratch but you may be able to talk to engineers at dynapower corp. they use this system for some of their equiptment.
for d.c. current under 25,000 amps, a calibrated resistor is used and industory standard is 50mv @ rated current. this allows the use of standard meter bodys and a custom scale.
for a.c. current measurement a "ct" is used (current transformer) there is a window for the conductor to pass through and there is a ratio rateing on the ct. usualy the ratio is the max current rating-to-five such as " 1000:5 " the ratio means that with 1000 amps passing through a conductor, through the window of the ct, there will be 5 amps flowing through the ct circuit.
this will be true, even with a dead short. NEVER open the ct circuit with power applied. the ct will act as a step-up transformer with a huge turns ratio.
ct are available with many diferent window sizes and ratios.
> this will be true, even with a dead short. NEVER open the ct circuit with power
> applied. the ct will act as a step-up transformer with a huge turns ratio.
Tim,
This is a very important warning. I agree, and want to add NEVER place a circuit breaker to the CT circuit.
