Sistemas eléctricos I

17. A series-wound dc electric motor will normally require. more current at high RPM than at low RPM. approximately the same current throughout its operating range of speed. more current at low RPM than at high RPM. high resistance will develop in stripping nicks.

18. A voltage regulator controls generator output by. introducing a resistance in generator- to-battery lead in the event of overload. shorting out field coil in the event of overload. Series wound. varying current flow to generator field coil.

19. Aluminum wire must be stripped very carefully because. high resistance will develop in stripping nicks. stripping nicks can cause short circuits. individual strands will break easily after being nicked. to prevent circuit failure due to terminal disconnection.

20. An ammeter in a battery charging system is for the purpose of indicating the. amperage available for use. total amperes being used in the airplane. rate of current used to charge the battery. stripping nicks can cause short circuits.

21. For general electrical use in aircraft, the acceptable method of attaching a terminal to a wire is by. crimping. soldering. crimping and soldering. Rolling.

22. How can it be determined if a transformer winding has some of its turns shorted together?. Measure the input voltage with an ohmmeter. The output voltage will be high. The transformer will get hot in normal operation. A high internal resistance condition.

23. How does the magnetic brake used to stop rotation of an electric motor armature operate?. Centrifugal force releases a rotating brake cog from a stationary notch when the armature reaches a certain speed and magnetic force re-engages the cog when the electrical power is turned off. A friction brake is applied by a magnet and released by a spring. approximately the same current throughout its operating range of speed. A friction brake is applied by a spring and released by a magnet.

24. How many cycles of ac voltage are produced in a six-pole alternator of the revolving-field type for each revolution of the rotor?. Four. Three. Six. Two.

25. If a generator is equipped with a vibrator-type voltage regulator, the actual time the voltage regulator points remain open. depends on the load carried by the generator. is controlled by the reverse- current cutout relay point clearance. is increased when the external load is greater than the generator output. motor can be operated in either direction.

26. If the reverse current cutout relay contact points fail to open after the generator output has dropped below battery potential, current will flow through the generator armature. in the normal direction and through the shunt field opposite the normal direction. and the shunt field opposite the normal direction. Centrifugal force releases a. opposite the normal direction and through the shunt field in the normal direction.

27. One purpose of a growler test is to determine the presence of. an out-of-round commutator. a broken field lead. a shorted armature. power output of the motor can be more closely controlled.

28. The commutator of a generator. changes direct current produced in the armature into alternating current as it is taken from the armature. changes alternating current produced in the armature into direct current as it is taken from the armature. reverses the current in the field coils at the proper time in order to produce direct current. total amperes being used in the airplane.

29. The method most often used in overcoming the effect of armature reaction is through the use of. interpoles. shaded poles. drum-wound armatures in combination with a negatively connected series field. opposite the normal direction and through the shunt field in the normal direction.

30. The only practical method of maintaining a constant voltage output from an aircraft generator under varying conditions of speed and load is to vary the. strength of the magnetic field. number of conductors in the armature. speed at which the armature rotates. amperes and frequency must both be equal.

31. The pole pieces or shoes used in a dc generator are a part of the. armature assembly. field assembly. brush assembly. Inverter drive motor.

32. The starting current of a series-wound dc motor, in passing through both the field and armature windings, produces a. low starting torque. speed slightly higher when unloaded. high starting torque. Starter motor.

33. The type of electric wire terminals used for most aircraft applications, in addition to providing good current carrying capabilities, are designed primarily. to prevent circuit failure due to terminal disconnection. for uncomplicated and rapid circuit connection and disconnection. for permanent connection to the circuit. Reduce field strength.

34. To test generator or motor armature windings for opens,. place armature in a growler and connect a 110V test light on adjacent segments; light should light. check adjacent segments on commutator with an ohmmeter on the high resistance scale. use a 12/24V test light between the armature core segments and the shaft. rate of current used to charge the battery.

35. To what depth is the mica insulation between the commutator bars of a dc generator undercut?. One-half the width of the mica. Equal to twice the width of the mica. Equal to the width of the mica. Three-half the width of the mica.

36. What is a cause of generator brush arcing?. Seating brushes with No. 000 sandpaper. Carbon dust particles. Low spring tension. amperes and voltage must both be equal.

37. What is the color and orientation of the position lights for navigation on civil airplanes?. Left side - green, right side - red, rear aft - white. Left side - red, right side - green, rear aft - white. Left side - white, right side - green, rear aft - red. Left side - White, right side - red, rear aft - white.

38. What is the minimum bend radius for an electrical wire bundle?. Forty times the outside diameter of the bundle. Five times the outside diameter of the bundle. Fifteen times the outside diameter of the bundle. Ten times the outside diameter of the bundle.

39. What is the most accurate type of frequency-measuring instrument?. Integrated circuit chip having a clock circuit. Electrodynamometers using electromagnetic fields. Electromagnets using one permanent magnet. checked with a milliamp ammeter.

40. What is the principal advantage of the series-wound dc motor?. High starting torque. Suitable for constant speed use. Low starting torque. speed of the motor can be more closely controlled.

41. When ac generators are operated in parallel, the. amperes and frequency must both be equal. frequency and voltage must both be equal. amperes and voltage must both be equal. shaded poles.

42. When approved, splices may be used to repair manufactured harnesses or installed wiring. The maximum number of splices permitted between any two connectors is. Four. Two. Three. One.

43. Which motor would be most likely to have an armature brake?. Starter motor. Landing light retraction motor. Inverter drive motor. field assembly.

44. Which of the following is most likely to cause thermal runaway in a nickel-cadmium battery?. A high internal resistance condition. Excessive current draw from the battery. Constant current charging of the battery to more than 100 percent of its capacity. has at least a residual charge before removing it from the circuit.

45. Which type of dc generator is not used as an airplane generator?. Externally grounded. Series wound. Compound wound. Shunt-type ohmmeter.

46. Electric wire terminals for most aircraft applications must be what type?. Slotted. Hook. Ring. Tappered.

47. How should the splices be arranged if several are to be located in an electrical wire bundle?. Staggered along the length of the bundle. Grouped together to facilitate inspection. Enclosed in a conduit. soldering.

48. In a generator, what eliminates any possible sparking to the brush guides caused by the movement of the brushes within the holder?. The brush pigtail. Brush spring tension. Undercutting the mica on the commutator. A friction brake is applied by a magnet and released by a spring.

49. Some electric motors have two sets of field windings wound in opposite directions so that the. speed of the motor can be more closely controlled. power output of the motor can be more closely controlled. motor can be operated in either direction. a broken field lead.

50. What type of instrument is used for measuring very high values of resistance?. Megohmmeter. Shunt-type ohmmeter. Multimeter. introducing a resistance in generator-to-battery lead in the event of overload.