This animated video explains the basic principles underpinning the operation and control of the Brushed DC motor. We start with an easy to understand mental model rooted in fundamental physics (the Lorentz Force and the Left Hand Rule), then progress to a basic model of the DC motor (incorporating back EMF) and how they can be controlled using modern chopper circuits. I focus on 4 types of DC motor - Permanent Magnet and then the 3 wound varieties: Separately Excited, Shunt and Series.
I also explore some more in-depth topics such as flux weakening and armature control.
Please let me know if you have any comments on this video!
00:00 Introduction
00:19 Summary of topics
01:00 The Lorentz Force
01:49 The 3 Basic Requirements
03:00 The Permanent Magnet DC Motor
05:15 Commutators
07:35 Back EMF
08:37 The Voltage Balance Equation
10:19 The Speed/Torque Regulation curve
11:19 Why is regulation so good in constant flux machines?
12:00 DC motor control
15:36 The need for more efficient voltage control
16:00 How chopper circuits work and control loops to regulate torque and speed
19:03 The Separately Excited DC Motor
19:49 Why is speed inversely proportional to field? - intro to flux weakening
22:30 The Shunt DC Motor
24:07 The Series DC Motor
26:00 Conclusion
