Understanding How the DC Generator Works
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| 1. A generator is a device that converts ____ energy into ___ energy | mechanical electrical
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| 2. What happens when a conductor cuts magnetic flux lines? | Voltage is induced into the conductor
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| 3. DC generators operate on the principle of ___ | electromagnetic induction
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| 4. Explain, according to Flemings Generator Rule, the meaning of the extended digits. Label what each digit represents. | thumb = thrust
pointer= point of field
middle finger = current
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| 5. How much voltage is being produced when the rotating conductor is parallel to the magnetic flux lines? | zero
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| 6.Maximum voltage is induced into a conductor when it cuts the magnetic field at ___ degrees. | 90 degrees (? page 225 in text)
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| 7. ___ voltage is induced into the conductor when the loop is at 0degrees, 180, and 360 in relation to the field. | zero
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| 8. When a conductor loop is continuously rotated in a magnetic field, the ___ output voltage follows the ___ function | AC sine
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| 9. To convert the AC voltage from the armature to DC voltage, DC generators make use of a | commutator
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| 10. How does a commutator cause the AC voltage that is generated appear as a DC voltage output | cuts off half the AC wave
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| 11. When AC voltage is generated and then converted to DC voltage by use of a commutator, is the voltage a constant output? | No, it is pulsating
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| 12. The frequency of the pulsating DC output voltage of a generator is ____ that of an AC generator | twice
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| 13. What is the name of the rotating member of the DC generator | armature
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| 14. What three components make up the armature | iron core, commutator, windings
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| 15. What are the three types of armature windings found in generators. | lap wound, wave wound, and frog leg
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| 16. The wires connected to the brushes of a generator are designated ___ and ____ | A1, A2
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| 17. ____ wound armatures are probably the most commonly used because they are designed for moderate voltages and moderate currents. | frog leg
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| 18. ___ wound armatures are used in machines designed for low voltage and high current. | lap
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| 19. ____ wound armatures are used in machines designed for high voltage and low current. | wave
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| 20. What are brushes made of and why | carbon based materials because they can deal with a lot of heat
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| 21. What is the function of pole pieces installed in the generator housing | To concentrate the magnetic field
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| 22. What is the physical relationship between the pole pieces and the field windings in the generator | pole pieces mounted on generator. field windings wound around pole
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| 23. Are permanent magnets ever used as the field poles in a generator | yes, they are used when the field is permanently mounted in stator
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| 24.What are the two types of connections for generator field windings | series and shunt
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| 25. The Series Field windings are made up of ___ (few/many) turns with large wire and the leads are labeled ___ and ____ | few, S1, S2
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| 26. How is the Shunt Field connected in a generator? How are the leads tagged? | Paralell / F1, F2
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| 27. The Shunt Field has a ___(high/low) resistance because it is made of ____ (large/small) wire | high, small
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| 28. When a load is connected to a series generator, the output voltage _____ | increases
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| 29. A series generator is ___ with residual magnetism | self excited
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| 30. As additional loads are connected to a series generator, the output voltage will continue to ___ until the iron in the pole pieces and armature becomes ____ | increase, saturated
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| 31. What three factors determine the level of the output voltage of a series generator | 1. strength of magnetic field produced by pole pieces.
2. number of turns of wire on the armature
3. speed of rotation or armature
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| 32. Based on your answers to the two previous questions, series generators would be best used with a (constant/varying) load | constant
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| 33. Self-excited shunt generators make use of __ to start the generation process | residual magnetism
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| 34. The shunt type of generator provides ____ output voltage before the load is applied | full
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| 35. As the load is increased on a shunt type generator, the output voltage will _____ | decrease
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| 36. To control the output of a shunt generator, a(n) ___ is installed to sense changes to the output current and to make adjustments to the shunt field current | electronic voltage regulator
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| 37. compound generators make use of a(n) ___ field winding and a(n) ____ field winding. | series shunt
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| 38. What is the primary advantage of a compound generator | overcome voltage problems
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| 39. A long shunt compound generator has the ___ in parallel with the ___ winding and the armature | shunt winding (into larger connection point) series
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| 40. The short shunt compound generator has the shunt field connected in parallel with the ___ | armature
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| 41. What is Cumulative Compounding | fields aid each other
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| 42. What is Differential Compounding | oppose each other
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| 43. In an Over-compound Generator, the load voltage is____(less than/equal to/ greater then) the no load voltage | greater
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| 44. In an Under-Compound Generator, the load voltage is ____(less than/equal to/ greater than) the no load voltage | less than
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| 45. In a Flat Compound Generator, the load voltage is ___(less than/equal to/ greater than) the no load voltage | equal to
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| 46. The greatest generator loss is due to the ___ of the windings | resistance
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| 47. Power loss due to induced currents in the core material of a generator is called ___ loss | eddie current
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| 48. ___ loss is due to molecular friction | hysteresis
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| 49. Almost all power losses in a generator, with the exception of flux linkage, are manifested in the form of ____ | heat
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| 50. The two primary magnetic flux fields in a generator are field flux and ___ flux | armature
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| 51. The magnetic neutral plane will shift in the direction of the ____. | armature rotation
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| 52. To prevent a shift in the neutral plane, ___ windings are installed in the generator to cancel the effects of self-induction in the armature. | interpole
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| 53. When DC generators are connected in parallel, an equalizing connection is used to connect the ___ fields of the two mahines in ___ with each orther | series, parallel
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| 54. What might happen if two DC generators are simply connected in parallel without an equalizer connection | generator will work against each other
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Created by:
JoshHampton