H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
H01F29/00—Variable transformers or inductances not covered by group H01F21/00
H01F29/08—Variable transformers or inductances not covered by group H01F21/00 with core, coil, winding, or shield movable to offset variation of voltage or phase shift, e.g. induction regulators
H01F29/10—Variable transformers or inductances not covered by group H01F21/00 with core, coil, winding, or shield movable to offset variation of voltage or phase shift, e.g. induction regulators having movable part of magnetic circuit