The utility model relates to an intermediate frequency electric welding unit belongs to spot welding unit technical field. It includes engine body, engine output axle, rotor subassembly and stator module, and rotor subassembly inner circle is equipped with stator module, is equipped with the clearance between rotor subassembly and the stator module, and stator module fixes on engine body, the rotor subassembly includes the rotor base, is equipped with a 12N stator slot on the inside wall of rotor seat surface to stator module, and N is the positive integer, and every stator slot is embedded adorns a magnet steel, and the magnet steel magnetic pole in the adjacent stator slot sets up on the contrary. The utility model discloses be 12 multiple with the design of the stator number of slots, the rotor adopts the permanent magnet to N S N S's order is inlayed respectively in the rotor inboard, provides the permanent flux volume, the stator coil winding for the winding of different pitches establish ties, parallelly connected, provide special wave form, cut ripples and fine ripples effectively, provide high efficiency, energy -conserving reliable electric welding voltage for the welding.