Cored Rogowski coil...

[Externet]

Good day.

Cut a strip of thin iron sheet (a coffee can after surgery by scissors) Say 25mm x 100mm x 0.5mm. Cover sharp edges with some vinyl-electrical tape.

Wind maaany turns of fine wire coil from left towards right and keep winding back towards the starting point.  Both coil ends are at the same side.  That is sort of a Rogowski coil, with a flexible metal core. -I think-

Now wrap the bendable strip coil thing onto an AC current carrying wire as the lower sketch. 

Will the winding present some voltage proportional to the big wire current ?

 

-Ignore the decorative print at lower right-