selektor 1975-06

Although Britain now seems to have finally decided not to go ahead with the Channel Tunnel project, we have heard about another Tunnel Project from this side of the Channel, which seems a good deal more likely to be successful. It is a process for winding rectangular relay" coils at a speed of 30,000 turns per minute. A conical tube is used as a winding tunnel, and the coil former is held stationary at the mouth of the tunnel as the latter rotates. The wire is led through a guide hole which is pierced through ceramic material at the tunnel mouth. The peripheral velocity of the rotating tunnel builds up to 300 km/h, and the inertia of the wire makes it follow a spiral path as it passes through. This spiral works like a spring which `takes up` the rapid changes in the speed at which the wire is paid out, as it winds onto the rectangu- lar former.