Physical Considerations on Magnetic Circuit with an Air-Gap

The changes in magnetic flux density distribution which occur when air gaps from 1 to 30 mm long are opened in an I-shape magnetic body were measured. The magnetic flux density distribution was found to be shifted relative to the distribution at an isolated end of the body, due to the magnetic interaction between the bodies across the gap. By taking this interaction into account, it is possible to determine the change in flux density due to the gap.