Chapter 2 Troubleshooting and Testing the DC Machine

44. What will happen to the armature if the shunt field opens while it’s operating with no load (page 90)?

45. Loose coils can lead to a grounded or open circuit (page 91). T_ Fclip_image002

46. An open coil in a two-parallel circuit shunt field willclip_image004 of the shunt field (pages 91-92).

a. lower the resistance

b. raise the resistance

47. An insulation breakdown between the shunt and series fields is usually caused by high amperes in the series field (page 94). T_ Fclip_image006

48. Running a compound DC machine without the series field is a quick way of ruling out the series field as the problem (page 94). T_ Fclip_image008

49. The resistance of the series field has very little effect on the amperes of its circuit (page 94). T_ Fclip_image010

50. A grounded series field coil may not show a problem (page 95). T_ Fclip_image012

51. The shunt field should never have AC voltage applied to it, because the series field will be destroyed by the high voltage being transformed into it (page 97). T_ Fclip_image014

52. Leads Fl and F2 are usually larger than the rest of the DC machine’s leads (page 99). T_ Fclip_image016

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