What is the fine-grained topic of the following text: An Easy to understand and also Cost-Efficient Design: A long-term magnetic industry is developed in the stator, or fixed section, of the electric motor by either irreversible magnets, which are typical in fractional horsepower applications, or electro-magnetic windings, which are made use of in applications that require 5 or even more horsepower. Only return the topic.
Design and functionality of an electric motor