A magnetic Yoke is a portable device for detecting surface and sub-surface cracking in any ferro-magnetic material.
Electromagnetic yokes produce their magnetism by wrapping a ferrite or soft iron “U” shape with a wire coil. Often the legs are adjustable to allow for irregular shaped parts. Because the coil is an electromagnet, the field can be turned “OFF” and “ON,” allowing easy removal of the part from the coil.
A yoke has an electric coil in the unit creating a longitudinal magnetic field that transfers through the legs to the examined part. The yoke technique is easy to use with minimal training. It can be used indoors, outdoors, inside vessels and tanks, and in all positions.
The magnetic yoke consists of a backing bar, permanent magnets, pole shoes and brushes.