Magnetic core structure

Claim 1

A MAGNETIC CORE COMPRISING A PLURALITY OF LAYERS OF LAMINATIONS OF MAGNETIC STRIP MATERIAL ASSEMBLED TO FORM AT LEAST ONE CLOSED LOOP HAVING A CROSS-SECTIONAL AREA OF THE CRUCIFORM TYPE, SAID CORE HAVING A CENTRAL PORTION, SAID CENTRAL PORTION OF SAID CORE INCLUDING A FIRST GROUP OF LAMINATIONS PREDOMINANTLY FORMED FROM MAGNETIC STRIP MATERIAL OF A FIRST PREDETERMINED WIDTH, THE BALANCE OF THE LAMINATIONS IN SAID FIRST GROUP BEING OF A SECOND PREDETERMINED WIDTH LESS THAN SAID FIRST PREDETEMINED WIDTH AND INTERLEAVED WITH THE LAMINATIONS OF SAID FIRST PREDETERMINED WIDTH IN SAID FIRST GROUP TO PROVIDE A PLURALITY OF DUCTS THROUGH WHICH A COOLING MEDIUM MAY PASS, THE NUMBER OF LAMINATIONS OF SAID FIRST PREDETERMINED WIDTH BEING GREATER THAN THE NUMBER OF LAMINATIONS OF SAID SECOND PREDETERMINED WIDTH IN SAID CENTRAL PORTION TO MAKE THE DUCTS NARROWER THAN THE DISTANCE BETWEEN THE DUCTS, A PLURALITY OF GROUPS OF OTHER LAMINATIONS DISPOSED ON OPPOSITE SIDES OF SAID CENTRAL PORTION, THE WIDTHS OF THE LAMINATIONS IN THE GROUPS OF SAID OTHER LAMINATIONS DECREASING IN STEPS IN EACH GROUP IN A DIRECTION AWAY FROM SAID CENTRAL PORTION, AND THE WIDTH OF THE LAMINATIONS IN ONE OF THE GROUPS OF SAID OTHER LAMINATIONS BEING SUBSTANTIALLY THE SAME AS THE WIDTH OF THE LAMINATIONS OF SAID SECOND PREDETERMINED WIDTH IN THE FIRST GROUP.