This lesson covers the methods of controlling the speed of a DC motor. It delves into the armature voltage control method and the use of external resistance in the armature circuit. The lesson explains that to control the speed using the armature voltage method, the field circuit must be separated and a variable DC voltage applied. This is a crucial concept for anyone interested in understanding the mechanics of DC motors and their speed control mechanisms.
01:19 - Introduction to the field control method, also known as field current control
08:32 - Discussion on the impact of reducing the field current on the armature current and the electromagnetic torque developed by the machine
16:04 - Explanation of the unsuitability of the field control method for constant mechanical load
27:52 - Discussion on the suitability of the field control method for constant power load