Abstract: In an induction heating apparatus, direct sensing of the high frequency high power current flowing in the tank circuit to load the induction coils, is obtained with a coil current measuring transformer comprising one of the power current busses leading to the induction coil and a secondary winding of many ampere-turns wound around said one bus. The bus is given a half-loop shape to accommodate the secondary winding. The secondary winding is made of a magnetic core wound with many turns of Litz wire. Cooling tubes are cemented outside the wound secondary with conductive cement to form a heat sink with a circulation of cooling medium through the tube. The cement is divided in two parts separated by gaps to prevent circulation of induced currents. A cooling tube is installed between the core and wound wire to provide an internal heat sink.