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Transcript
Student__________________ Chapter 20 Review Questions Troubleshooting Electric Motors October 2010 WEEK 8b HVAC Tyrrell 1. True or False If a sleeve bearing fails in a small fractional horse power motor, the motor is generally replaced 2. An open winding in an electric motor means a. The winding is making contact with the motor frame b. One winding is making contact with another one c. A wire in the winding is broken d. The centrifugal switch is open to the start winding 3. There is a short circuit in an electric motor winding when a. There is an adverse weather condition b. A winding conductor is worn bare and touches another part of the conductor that is also bare c. There is a defect in the centrifugal start switch d. The motor will not start 4. An opened winding or a shorted winding can be determined with which of the following instruments? a. Voltmeter b. Ammeter c. Ohmmeter d. Speedometer 5. Decreased resistance will cause the amperage to a. Decrease b. Increase c. Not increase or decrease d. None of the above 6. A_____________________ may be used to detect resistances in the millions of ohms? 7. What resistor size do they recommend for discharging a capacitor?__________ohm 8. State the physical difference between the start and run capacitor 9. In 3 phase motors in good condition, should the resistance be the same across any 2 windings? - circle YES NO 10. Describe what may happen to an electric motor if the drive belt is too tight. 11. Loose electrical connections may result in a __________- in voltage and an ________________________ in amperage 12. Amperage is checked with a _______________ 13. TRUE or FALSE - If a motor bearing is dry or worn out you can expect to see an increase in amperage. 14. Tag the different components in this motor drawing 1. Start winding 2. Run winding 3. Capacitor 4. Centrifugal switch