Rogowski coils simplify current, power measurement

If i am measuring currents at 50Hz...no harmonics...no noise...just 50Hz...do I need the integrator? Surely the integral is going to be identical to the measured signal ..just shifted 90 degrees. So why bother? many thx

Ted Crum said: "The coil itself is just a toroidal current transformer" No it's not. The main difference is that a Rogowski coil has an AIR-core. This results in a linear transfer behaviour. It also means that the secondary circuit can not have any load - there is practically no current induced by the coil - only voltage. Now the most important difference resulting from the air-core: the RATE OF CHANGE (yes, the derivative) of the secondary VOLTAGE is proportional to the primary CURRENT. To get a value that is directly proportional to the primary current the signal has to be integrated. More info: h*ttp://students.uta.edu/cx/cxl7817/publication/2003RogowskiCoil.pdf (Just a quick google search - no special recommendation)

At 1/4/2008 6:29:34 AM, Gregory M. said: "Rogowski was a talented Polish electrical engineer who lived in the beginning of the XX century and designed many useful gadgets" Not quite. Rogowski was a German scientist. h*ttp://en.wikipedia.org/wiki/Walter_Rogowski

Ohio Semitronics, Inc. in Hilliard, OH offers a full line of Rogowski coils and integrators. www.ohiosemitronics.com

PEM also offers rogowski coils. There is some good information about rogowski coils at www.pemuk.com/howitworks.html

This sounds very musch like a hall effect sensor.

I need to buy a sensor type rogowski coil, can anybady help me?, if you can please write to bigfercho16@hotmail.com thanks so much.

I have used Rogowski coils as wideband current sensors in intelligent grid applications where we wanted to capture transient phenomena. In fact I had one custom-built by a South African company called Sure Engineering.

Anybody knows how rogowski coil can be incorporated on PCB as transducer for measurement of current? Any Article?

I look at Rogowski coils like accelerometers. Especially when measuring DC currents. You get a polar signal representing the onset of current, and a coresponding opposite polarity pulse when the current is turned off. I have measured 305,000 DC amps using a twin coil setup and integrator supplied by High Current Technologies. Great stuff.

Wow ? how confusing. People think that you have drawn a current transformer. A Rogowski Coils, some times called a Chattock coil, is a pretty amaizing device. It is an air core transformer. It is typically wound like an air core inductor, on a flexible piece of rubber, such that both terminals exit the same end. It can then be wrapped around conductors to form a loop around the conductor to be measured. It captures only the flux surrounded by the loop and ignores all else, so it is great for making very accurate measurements in very noisy or high flux environments. It has no core so it can not saturate, this allows it to be accurate at very large range of currents. An 8 ounce Rogowski coil can make the same measurements as a 100 pound current transformer. No core also makes it very, very fast. It can be used to measure large fast current pulses. We used it to measure a 1 us wide, 5000 amp pulses, needed to turn on GTO?s and IGCT?s. A normal Current Transformer could not see these pulses at all. They are very useful as a test instrument as it is open ended it can be wrapped around existing conductors with out breaking the circuit. The main draw back is the electronic integrator

When used during the 2nd WW there was much spirited discussion as to which wood should be used to wind the wire about. Spruce was said to be preferable, according to many users!

You can get around the uneven winding issue by specifying an aluminum core box. The conductive core box distributes the external flux eddy currents evenly around the toroid. There is also a minimum of flux leakage from a toroidal core.

Here is a link of using a Rogowsky coil to measure upto 100,000A h t t p : / /tesladownunder.com Under Can Crushing.