The role of cut to length in the transformer core making

Transformer core is the heart of transformers. Cut to length line play an important role in the transformer core manufacturing.

It directly affects the transformer product technical performance, efficiency, material loss and series of problems. The experts agree that the transformer core cutting machine is the key equipment in the transformer manufactory.

 In order to improve the transformer products development, and improve the low efficiency, poor accuracy, core cutting waste, products of higher no-load loss and backwardness, China design research units and manufacture factory invested a lot of manpower and work in the development of transformer core cutting machine from the 1960s.There are four generations of core cutting machine have been developed before and after.

1. The first generation line is a simple mechanically positioned cut to length. This design based on less cost, fast design, so it is simple in structure, and less mechanization of production line. Workers manually assist the position, take the laminations, and the V notching and the tip of middle leg need punched in the open type press machine, and the electrical part is also simplified.

2. The second generation line is a mechanical center position cut to length, with a higher mechanization degree. At the end of 1970s, the transformer can be adopted by the core without hole, and could be mitered core, and low loss transformers, but must be improve the quality and enhance the international competitiveness of small and medium-sized transformer products to make the mitered core cutting to produce in mass. Domestic research unit cooperated with transformer factory to develop the cut to length, which is succeeding in 1983. This line can cut 50-60 thousand KVA annually. The quality is good, length tolerance is not more than 0.2mm, angle degree not more than 0.025, lamination burr is less than 0.03mm, average iron loss is less than 824W, less than the design insurance requirement value of 920W.

Mechanical block center position, V notching, punching adopted cylindrical rolling guide, cutting tools are made of hard alloy steel, feeding machine with small inertia DC motor. The operation is simple and labor saving, but the main control circuit is the sequential control made, with more relay, high failure rate and the mechanical block position also restrict the high speed, so the production efficiency is low.

3. The third generation line is a microcomputer controlled cut to length, this mostly adopted the second generation design principle, which difference is that the position method controlled by computer. Through the measuring roller and numerical control constant feeding, it can improve the cutting precision and can better ensure the cutting precision, max feeding rate is 150m/min.

4. The fourth generation line is Model of 600-900 numerical control cut to length, this line is on the basis of actual situation of our country and digestion and absorption of foreign cut to length lines. The line is controlled by computer and the automation is high, operation is simple. The operation control knob can automatically complete the cuttings.

At present, its automation, control degree and performance nearly reached to the international level and basically achieved the substitution for similar products in Europe and America.