AC/DC Motor Theory

Overview

The AC/DC Motor Theory course was specifically developed for electricians and electronic technicians as well as for the multi-craft training needs of process and manufacturing facilities. This course consists of 11 interactive, on-line lessons that address AC and DC motor theory.

Objective

• Identify the components of an AC Motor and explain their function.
• Explain the basic principles of magnetism.
• Interpret the characteristics of a current as represented on a sine wave.
• Describe the effect of AC current on a conductor.
• Describe the methods of increasing magnetic flux in a conductor.
• Explain how a rotating field is created in an AC Motor.
• Explain and be able to calculate synchronous speed.
• Explain induction and its effect on a rotor.
• Explain the relationship between phased current and rotor spin.
• Explain slip and know its formula.
• Describe the design of a squirrel cage rotor and function of components.
• Describe the design of a wound rotor and function of a wound rotor’s components.
• Define torque and explain its role in motor operation.
• Explain the design of a reluctance motor and how it works.
• Explain the design of an externally excited motor.
• Explain how an externally excited motor works.
• Explain the function of a motor starter and the most common types of motor starters.
• Describe a variable speed drive and its effect on voltage and frequency.
• Distinguish a single-phase motor from a three-phase motor.
• Explain the design of a split-phase motor and how it works.
• Explain the design of a capacitance start motor and how it works.
• Identify the general characteristics and advantages of a DC motor.
• Identify the basic components of a DC motor.
• Explain the function of DC motor components.
• Identify the components of the armature and brush assembly; explain their function.
• Explain the effect of armature current on the main flux field and motor action
• Explain the process of commutation and how it maintains direct current in a DC motor.
• Describe how the number of windings and commutator segments effects torque and mechanical power of a DC motor.
• Explain how armature reaction shifts the neutral plane in a DC motor.
• Explain how armature reaction affects motor operation.
• Explain what measures will correct armature reaction.
• List the requirements for induced voltage in a motor.
• Explain counter-EMF.
• Explain the design of a series wound DC motor and how it works.
• Explain the design of a shunt wound DC motor and how it works.
• Explain the design of a compound wound DC motor and how it works.
• Explain the design of a permanent magnet DC motor and how it works.
• Explain how a universal motor runs off of DC power.
• Explain the design of a brushless DC motor and how it works.
• Explain why a reduced voltage starter is sometimes needed in a motor.
• Explain how a reduced voltage starter works.
• Explain what determines the direction of rotation of a DC motor.
• Explain how a reverse contactor works.
• Explain how to control the speed of a DC motor.
• Explain how a tapped resistor works.
• Explain a DC drive’s control system and how it works