Torque, Speed and Back EMF in Motors — Lesson 5

This lesson covers the fundamental concepts of torque, speed, and back electromotive force (EMF) in motors. It explains how torque is related to current, and how the optimization of this relationship is defined by the angle theta in the Maximum Torque Per Angle (MTPA) algorithm. The lesson also introduces Faraday's law, explaining how changes in flux result in the production of an electromotive force or voltage. It further discusses the concept of speed, the relationship between mechanical and electrical speed, and the impact of back EMF on motor performance. The lesson concludes with an assignment to calculate the back EMF constant and electrical frequency of an eight-pole motor.

Video Highlights

00:17 - Introduction
01:19 - Faraday's law and its application in motor operation
02:58 - Back EMF and its generation in a motor
04:51 - Explanation of PMDC motor dynamics
11:32 - Home assignment
15:14 - Concept of mechanical and electrical speed in a motor
20:40 - Concept of back EMF constant and its calculation
27:46 - Home assignment

Key Takeaways

- Torque in a motor is directly related to the current. The greater the current supplied, the more torque will be delivered.
- The relationship between torque and current is optimized by the angle theta in the MTPA algorithm.
- Faraday's law states that changes in flux result in the production of an electromotive force or voltage.
- The speed of a motor is influenced by the applied voltage and the load torque.
- The back EMF of a motor is proportional to its mechanical speed and impacts the motor's performance.