Lesson 1 - Introduction to Single-Phase Motors
Motor parts; NEMA motor standards and enclosures; Nameplate data; Induction motors; Stator, rotor field; Split-phase starting; Synchronous speed; Starting switches
Learning Objectives:– List the parts of a rotor.
– List the data given on a typical motor nameplate.
– Explain how an induction motor works.
– Demonstrate how to calculate the number of electrical degrees in one complete rotation of a motor.
– Explain how a centrifugal switch works.
Lesson 2 - Split-Phase Motors
Motor connections; Skein and consequent-pole windings; Two-speed, three-, four-winding, and dual-voltage motors; Troubleshooting
Learning Objectives:– State the reason why a second stator winding is important in the single-phase induction motor.
– Explain how to identify motor leads when there are no tags or colors to identify them.
– Describe a skein winding.
– List the ways to change the speed of a motor by changing the number of poles.
– Discuss some common motor problems.
Lesson 3 - Capacitor Motors
Kinds and operation; Rotating magnetic fields; Single-voltage, dual-voltage, reversible, capacitor-start, and capacitor-run motors
Learning Objectives:– State the definition of a capacitor.
– Explain how to make a split-phase motor operate as a capacitor-start motor.
– Explain how the running windings are connected to make a dual-voltage motor run on either 120 or 240 volts.
– List problems that cause the circuit breaker to trip when you turn on a capacitor motor.
Lesson 4 - Repulsion Motors
Repulsion principle; Purpose of brushes; Short circuiter; Commutator; Repulsion, compensated repulsion, and repulsion-induction motors
Learning Objectives:– Discuss the operating principles of a repulsion-start induction-run motor.
– Explain how to seat new brushes on the commutator.
– Discuss the functions of the major motor components.
– List the reasons a repulsion motor might fail to start.
Lesson 5 - Universal Motors
Performance characteristics; Speed control; Motor life; Universal motor assemblies; Ventilation; Brush mounting and selection
Learning Objectives:– Explain eddy current loss in the universal motor.
– List the advantages of a universal motor.
– Explain how the speed of the universal motor is controlled.
– List the criteria for selecting carbon brushes for universal motors.
– State reasons why a universal motor might have poor torque.
Lesson 6 - Special Motors
Shaded-pole, synchronous, hysteresis, unexcited synchronous, induction, reluctance, and permanent-magnet motors
Learning Objectives:– State the definition of a salient pole.
– Explain the operating principles of a shaded-pole motor.
– Discuss the operating principles of a hysteresis motor.
– Explain the difference between an unexcited synchronous motor and an excited synchronous motor.
Lesson 7 - Synchros
Rotor and stator construction; Synchro assembly and transmitter operation; Receivers; Control synchro systems; Control transformer
Learning Objectives:– State the definition of the term synchro.
– Describe motor construction in a synchro.
– Demonstrate how to calculate terminal-to-terminal stator voltage.
– State the reason why the control transformer is important in a synchro control system.
– Explain how to connect a differential synchro system.
Lesson 8 - Servos
Servomechanisms; Amplidyne operation; Overtravel control; DC and AC servomotors; Servo-control bridges; Servo actuators
Learning Objectives:– State the definition of a servomechanism.
– List the four characteristics needed to keep a regulated quantity matched to a reference valve in a servomechanism.
– Explain how an amplidyne control system works.
– Discuss how to control overtravel in a servomechanism.
Lesson 9 - Motor Installation
Conductor size; Preventing shorts and grounds; Controllers; Overcurrent protection; Guards; Grounding; Fuses; Starters; Service factor
Learning Objectives:– Explain how to determine conductor size for motors.
– State the definition of a controller.
– List the conditions under which the frames of stationary motors must be grounded.
– Demonstrate how to determine the size of a dual-element when two or more motors are connected to one feeder.
– List the electrical and mechanical factors to consider in selecting a motor for a specific application.
Lesson 10 - Motor Maintenance
Procedures; Testing capacitors and stator windings; Armature defects; Noisy operation; Bearing problems; High temperatures; Incorrect speed
Learning Objectives:– Demonstrate how to test bearings for wear.
– Explain how to test capacitors.
– State the reason why proper belt tension in important.
– List the common causes of excessive brush sparking.