This lecture covers the principles of asynchronous machines, also known as induction machines. It begins with an introduction to the basic concepts and definitions, including the characteristics of the magnetic circuit and torque. The instructor explains the structure of the asynchronous machine, detailing the stator and rotor configurations, including the squirrel cage and wound rotor types. The functioning principle is elaborated, emphasizing the relationship between the rotating magnetic field and the rotor's speed. The concept of slip, which is the difference in speed between the rotor and the magnetic field, is introduced, along with its significance in torque generation. The lecture also discusses the equivalent circuit of the asynchronous machine, including parameters such as resistance and reactance. The instructor highlights the importance of understanding the power balance and the impact of starting methods on performance. Throughout the lecture, practical examples and visual aids are used to enhance comprehension of the theoretical concepts presented.