Flux Guides

Flux guides are geometric features — ferrite rails, C-cores, or shaped steel laminations — that channel magnetic flux from transmitter to receiver while limiting spill into the environment. In docks they improve k for a given coil area and help separate power flux from FOD sense zones when designed with FEM.

Guides interact with all nearby permeable and conductive materials; a flux guide that helps in CAD can hurt when a steel bolt head sits in the wrong place on the production line.

01Design approach

• Define intended flux tube between TX and RX in 3D FEM.
• Minimize flux crossing conductive loops (cable harnesses, frame rails).
• Include saturation checks on guide sections at max current.

02Manufacturing

Machined ferrite guides are precise but costly; molded ferrite suits volume. Tolerance on guide air gaps (similar to transformer gaps) tunes inductance — document shim procedures if used.

03Maintenance

• Debris in flux channels (metal swarf) detunes pads — sealed encapsulation helps.
• Guides chipped in collisions change field shape — inspect after impacts.
• Replacement guides must be paired sets TX/RX when coupling is optimized together.