Chapter 9 Review Questions Essay

1118 WordsNov 23, 20125 Pages
Fred Bear MAIR 1449.02 3-24-11 R.Q. Unit 9 (E.B.) 1. What is magnetism? When two pieces of iron are attracted to each other by physical means or electrical means. 2. Torque is A. Strength that a motor produces by turning. 3. A magnetic field is D. All the above. 4. True or False: A permanent magnet is a piece of material that has been magnetized and can hold its magnetic strength for a reasonable length of time. True. 5. How is an electromagnet produced? Through electricity. 6. Which of the following produces the best electromagnet? B. soft iron 7. Unlike poles of a magnet repel each other and like poles attract each other. 8. What part does polarity play in the operation of an…show more content…
The method of splitting the phase of incoming power to produce a second phase of power, giving the motor enough displacement to start. 20. What removes the starting winding from the electrical circuit of an open type split phase motor once it reaches 75% of its operating speed? Centrifugal switch. 21. What are the three probable areas of trouble in a split phase motor? The bearings, windings, and the centrifugal switch. 22. What is the unit of measurement for the strength of a capacitor? C. microfarad. 23. What is the purpose of the capacitor? To boost the starting torque or running efficiency of a single phase motor. 24. What is the difference between a running and a starting capacitor? Starting capacitors are usually made of plastic and used to assist a single phase motor in starting. A running capacitor has an oil filled case and is mainly used to increase a motor’s running efficiency. 25. List the five capacitor replacement rules. 1. The voltage of any capacitor used for replacement must be equal or greater than that of the one being replaced. 2. The strength of the starting capacitor replacement must be at least equal to but not more than 20% greater than the one being replaced. 3. The strength of the running capacitor replacement may vary by plus or minus 10% of the strength of the one being replaced. 4. If capacitors are installed in parallel, the
Open Document