Pancake Coil

Pancake coils are a form of rigid coil wound flat. These coils produce a radial field emanating from the centre of the coil to the outer edge.

Due to flux travelling radially, pancake coils are usually used to locate circumferential discontinuities.

The geometrical shape of the coils means the flux produced is more concentrated in the centre of the coil in comparison to the outer edge, resulting in a considerable difference in flux density. To account for the lower flux density at the outer edge, pancake coils should have a radius of at least 50mm larger that the component radius.