Magnetic gores of thin tape insulated by cataphoresis

SPIRALLY-WOUND insulated magnetic cores of thin tape play an important role in modern communication systems. In the telephone plant, high-frequency transformers are required in connection with the simultaneous transmission of a large number of messages over a single circuit. In radar, transformers developing high-power microsecond pulses having large components of energy at high frequencies are used extensively.¹ The trend toward high frequencies forced a reduction in the thickness of core laminations. This was necessary to maintain a high effective permeability and low core loss at the operating frequency. Of course, each lamination must be effectively protected against interlaminar welding during the final heat treatment that is required by all high permeability materials to develop their magnetic properties. This welding, unless prevented, permits eddy currents and sets up mechanical stresses which may impair magnetic properties.