Induction furnace
You probably did use low wattage unit.
An Induction Furnace is an electrical furnace in which the heat is applied by induction heating of metal. Induction furnace capacities range from less than one kilogram to one hundred tonnes capacity and are used to melt iron and steel, copper, aluminium and precious metals.Yes, there's a difference between a furnace and a stove top! :) But, it's that reversing magnetic field that gets those atoms excited. In case of the furnace the metal has to a conductor of electricity and have the eddy currents give the metal magnetic properties. And naturally, electrical resistance to the currents play a role in generating heat as well.
You probably did use low wattage unit.