After switching on, a fan starts, which cools the components inside the appliance and thus protects them from overheating. This fan makes a slight noise. A fan is essential for induction technology, its operating noise is part of the normal operation of an induction cooking plate and should not bother you. After a long period of operation, it is normal for the fan to run on in standby mode. Incidentally, operating noises are more audible on a free-standing induction cooking plate than on a built-in induction cooking plate.