(1) shell and core type iron core
The PART OF THE core winding is called "core column transformer core winding is not set, only the part of the magnetic circuit is called" yoke ". Where the core surrounds the winding is called shell; Where the winding encircles the core pillar is called the core type. Shell type and core type have their own characteristics, but the transformer manufacturing process determined by the iron core is very different, once a certain structure is selected, it is difficult to produce a structure. In China, most transformer cores are stacked core type.
(2) single-phase and three-phase cores
Single - phase iron core has a single two - column stack iron core. There are five kinds of single-phase single-column yoke four-column core, single-phase double-column stack core and single-phase radiant stack core. There are four kinds of THREE-PHASE core: THREE-PHASE column TYPE STACK core, three-phase SIDE-yoke type five-column core, three-phase double-FRAME STACK core and three-phase reactor stack core.
(3) three-dimensional and planar
The core pillar and yoke of the three-dimensional type are not in the same plane, there are radial type, involute type, symmetric type, because the magnetic flux distribution is more uniform, can reduce the loss; Flat core and yoke in the same plane, high mechanical strength, good manufacturability.
(4) Stack core and coil core
Generally are stacked iron core, from the iron core stacked. There are many forms of coil core. The air gap between the core and yoke of involute iron core is large, which affects the no-load current, so the capacity cannot be too small. However, due to the magnetic flux leakage entering the iron chip plane vertically, which affects the additional loss, the chip width should not be too large, that is, the capacity should not be too large.
The core is mainly composed of the core body, fasteners and insulation parts:
① Core body, magnetic conductor, made of electrical steel sheet.
② Fasteners, clips, screws, glass binding tape, just binding tape and pad, etc.
③ Insulation parts, clip insulation, insulation tubes and insulation pads, ground lugs and pads, etc.