S U M M A R Y This chapter explained the six types of induction motors commonly used by the HVACR industry. Induction motors have many similarities, but the operating principles differ for each type. Single- phase and three-phase motors require different connections to accomplish specific purposes. For single-phase motors, automatic start-up involves a start winding and start components. Trouble- shooting procedures require sufficient knowledge of each type of motor. Information on reversing rotation and connecting dual-voltage and multi- speed motors and how to check motor winding resistances were also covered. A discussion on the proper lubrication of motor bearings was included. The purpose, styles, and types of fans and blowers were explained, along with the importance of proper air movement to heating, refrigeration, and air conditioning systems. T E S T Y O U R K N O W L E D G E Answer the following questions using the information provided in this chapter. 1. Name two main parts of an electric motor. 2. A motor’s windings are located in its _____. 3. True or false? A magnetic field opposing the stator’s magnetic field is produced in a motor’s rotor by a process called induced magnetism. 4. One of the factors determining motor speed is the number of a motor’s stator _____. 5. Which of the motor windings determines direction of rotation? 6. True or false? The primary job of a start winding is to provide automatic starting of a single-phase motor. 7. The start winding must be disconnected at about _____% of normal motor speed. 8. On a hermetic compressor, why is the switch to disconnect the start winding located outside the shell? 9. What do the abbreviations LRA and FLA stand for? 10. Name the two most common motor problems. 11. Cycling on the overload can be caused by: A. Excess amperage draw. B. Excess motor heat. C. Excess compressor heat. D. All of the above. 12. Name five types of single-phase induction motors. 13. The PSC motor includes a _____ in series with its start winding. 14. A CSIR motor is basically a split-phase motor that includes a(n) _____ in series with its start winding. 15. A common form of motor protection uses a snap-acting _____ disc to make and break a set of contacts. 16. Name three methods used to check a capacitor. 17. True or false? Single-phase dual-voltage motors have two separate run windings. 18. How is the direction of rotation changed on a three-phase motor? 19. Name the three electrical terminals located on a single-phase hermetic compressor. 20. What test meter is used to check a motor for a short to ground or open or shorted winding? 21. Is an ECM an AC motor or a DC motor? Explain your answer. 22. List three benefits and three drawbacks of an ECM motor compared with a comparable AC motor. 520 Heating and Cooling Essentials Copyright Goodheart-Willcox Co., Inc.