Automatic EI-300 Lamination Stacking Machine for Large Power Transformer Core Assembly Line The EI-300 inserts E & I silicon steel laminations into transformer coil bobbins under PLC control. Positioning accuracy is ±0.02 mm, stacking accuracy ±0.1 mm, and cycle time is adjustable from 1 to 60 seconds, giving up to 250 stacks per minute. It is specified for the 8000-15000 VA band of large power transformers, where a single core carries a lot of lamination and a bad stack is