April 5, 2018

World’s widest core-cutting line now also in operation in Taiwan

Abstract Since steelmakers have started to produce grain-oriented electric strip in widths of up to 1,250 mm, producers of transformers have been increasingly demanding core-cutting...

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Abstract
Since steelmakers have started to produce grain-oriented electric strip in widths of up to 1,250 mm, producers of transformers have been increasingly demanding core-cutting lines capable of handling such wide strip. By processing wider strip, manufacturers reduce production costs while increasing the power efficiency of the transformers. GEORG is the only manufacturer in the world to offer core-cutting lines designed for these strip widths.

Keywords: core-cutting line, core laminations, 1,250 mm grain-oriented electric strip

Introduction
Taiwanese Manloy Trading Co., Ltd produces laminations for distribution and power transformers in its service centre in Nankan, to the north of Taipei. A GEORG core-cutting line for up to 600 mm wide sheet has already been in operation there for 28 years. In 2016, Manloy installed two new core-cutting lines from GEORG as part of a modernization and expansion program: a GEORG precision-cut TBA 1200 S for up to 1,250 mm wide sheet for power transformer cores, and a GEORG precision-cut TBA 400 ecoline machine for up to 440 mm wide sheet for distribution transformer cores.

Established 60 years ago, the service centre in Nankan was the first in Taiwan to specialize in electric steel strip processing for power and distribution transformers and electric motors. Today, three slitting machines and three core-cutting lines enable the company to meet market demands with flexible and high-capacity production capabilities. At 7,500 square metres, the warehouse can store up to 11,000 tons of steel coils.

Widest transformer core-cutting line in the world
Core-cutting lines of the GEORG precision-cut TBA 1200 series are worldwide the only ones capable of producing centre leg laminations of 1,250 mm width as single pieces. Manloy is among the first customers in the world to operate one of these lines.

Before now, core-cutting lines could only handle strip widths of up to 1,020 mm. For transformer cores requiring wider laminations, e.g. centre legs of 1,200 mm width, two sizes of laminations had to be cut , e.g. 400 and 800 mm wide, and then arranged in two adjacent stacks. With more and more steel producers offering grain-oriented electric strip in widths of up to 1,250 mm, the demand for core-cutting lines designed for such strip widths has recently seen a significant growth.

Wider strip provides various advantages. Fewer laminations need to be cut and manually stacked to a core. Additionally, centre legs consisting of one stack of laminations that fills the complete width provide a higher power efficiency than cores with two separate stacks of smaller laminations.

On the new line, Manloy produces laminations with centre lengths of up to 5,500 mm and thicknesses down to 0.23 mm, at a production capacity of 400 tons per month. Even at the maximum processing speed of 240 m/min, it achieves a cutting accuracy of one tenth of a millimetre.

A double coiler is arranged in the entry section of the line. Each coiler shaft is designed for a six-ton load. The coiler is equipped with an automatic threading unit and a forward feeding device. The punching section features two V-notch units and two CNC-controlled crosswise adjustable hole punch units for off-centre holes. The line also incorporates a slot punching unit and four tip-cutting shears.

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