Ignition and electrical test review
3. 18 Which federal aviation regulations specifies that each resettable circuit protective devices requires a manual operation to restore service after the device has interrupted the circuit? A. 14 CFR Part 23. B. 14 CFR Part 43. C. 14 CFR Part 91.
A. 14 CFR Part 23.
3. 15. Arcing at the brushes and burning of the commutator of a motor may be caused A. by weak brush springs. B. excessive brush spring tension. C. Low mica.
A. by weak brush springs.
3. 6. Accoraing to the electron theory of the flow of electricity, when a properly functioning DC alternator and voltage regulating system is charging an aircraft's battery, the direction of current flow through the battery A. is into the negative terminal and out the positive terminal. B. is into the positive terminal and out the negative terminal. C. cycles back and forth with the number of cycles per second being controlled by the rotational speed of the alternator.
A. is into the negative terminal and out the positive terminal.
3. 19. Electrical switches are rated according to the A. voltage and the current they can control. B. resistance rating of the switch and the wiring. C. resistance and the temperature rating.
A. voltage and the current they can control.
3. 27. Sharp bends should be avoided in ignition leads primarily because A. weak points may develop in the insulation through which high tension current can leak. B. ignition lead wire conductor material is brittle and may break. C. ignition lead shielding effectiveness will be reduced.
A. weak points may develop in the insulation through which high tension current can leak.
3. 5. What device is used to convert alternating current, which had been induced into the loops of the rotating armature of a DC generator, to direct current? A. rectifier. B. A commutator. C. An inverter.
B. A commutator.
3. 23. Aircraft electrical wire is manufactured in sizes according to a standard known as A. Military Specification (MS) • B. American Wire Gauge (ANG) • C. Technical Standard Order (TSO) .
B. American Wire Gauge (ANG) •
3. 25. What type of electric motor is generally used with a direct-cranking engine starter? A. Direct current shunt-wound motor. B. Direct current series-wound motor. C. Synchronous motor.
B. Direct current series-wound motor.
3. 7. Electric motors are often classified according to the method of connecting the field coils and armature. Aircraft engine starter motors are generally of which type? A. Compound. B. Series. C. Shunt (parallel).
B. Series.
3. 13. What type of lubricant may be used to aid in pulling electrical wires or cables through conduits? A. Silicone grease. B. Soapstone talc. C. Rubber Lubricant.
B. Soapstone talc.
3. 8. The generating system of an aircraft charges the battery by using A. constant current and varying voltage. B. constant voltage and varying current. C. constant voltage and constant current.
B. constant voltage and varying current.
3. 12. In order to reduce the possibility of ground shorting the circuits when the connectors are separated for maintenance, the AN and MS electrical connectors should be installed with the A. socket section on the ground side of the electrical circuit. B. pin section on the ground side of the electrical circuit. C. pin section on the positive side of the electrical circuit.
B. pin section on the ground side of the electrical circuit.
3. 22. Aircraft wire size is determined by using a(n) A. Ohmmeter B. wire gauge. C. dial caliper
B. wire gauge.
3. 24. What is the maximum number of bonding jumper wires that may be attached to one terminal grounded to a flat surface? A. Two. B. Three. C. Four
C. Four
3. 3. Why is it unnecessary to flash the field of the exciter on a brushless alternator? A. The exciter is constantly charged by battery voltage. B. Brushless alternators do not have exciters. C. Permanent magnets are installed in the main field poles.
C. Permanent magnets are installed in the main field poles.
3. 9 Which of the following aircraft circuits does NOT contain a fuse/circuit breakers? A. Generator circuit. B. Air-conditioning circuit. C. Starter circuit.
C. Starter circuit.
3.1. Upon what does the output frequency of an AC generator (alternator) depend? A. The speed of rotation and the strength of the field. B. The speed of rotation, the strength of the field, and the number of field poles. C. The speed of rotation and the number of field poles.
C. The speed of rotation and the number of field poles.
3. 14. Which of the following is regulated in a generator to control its voltage output? A. Speed of the armature. B. Number of windings in the armature. C. The strength of the field
C. The strength of the field
3. 28. Which of the following are included in a typical turbine engine ignition system? A. Two igniter plugs, two transformers, and two intermediate ignition leads. B. Two igniter plugs, one exciter unit, and two low-tension igniter leads. C. Two igniter plugs, one exciter unit, and two high-tension igniter leads.
C. Two igniter plugs, one exciter unit, and two high-tension igniter leads.
3. 17. When installing electrical wiring parallel to a fuel line, the wiring should be A. below the fuel Line. B. beside the fuel line. C. above the fuel line.
C. above the fuel line.
3. 26. Igniter plugs used in turbine engines have a long service life because they A. have a high intensity spark. B. operate continuously with a lower spark. C. do not require continuous operation.
C. do not require continuous operation.
3. 10. The maximum number of terminals that may be connected to any one terminal stud in an Aircraft electrical system is À. two. B. three. C. four.
C. four.
3. 2. Alternators (AC generators) that are driven by a constant-speed drive (CSD) mechanism are used to regulate the alternator to a constant A. voltage output. B. amperage output. C. hertz output.
C. hertz output.
3. 11. The constant current method of charging a nickel-cadmium battery A. will bring it up to fully charged in the shortest amount of time. B. will lead to cell imbalance over a period of time. C. is the method most effective in maintaining cell balance.
C. is the method most effective in maintaining cell balance.
3. 29. The primary advantage of pneumatic (air turbine) starters over comparable electric starters for turbine engines is. A. a significant lack of wear to the commutator. B. that it does not disengage until the engine reaches idle. C. its high power-to-weight ratio.
C. its high power-to-weight ratio.
3. 4. The part of a DC alternator power system that prevents reverse flow of current from the battery to the alternator is the A. reverse current relay. B. voltage regulator. C. rectifier.
C. rectifier.
3. 16. ON-OFF two position engine electrical switches should be installed A. so that the toggle will move in the same direction as the desired motion of the unit controlled. B. under a guard. C. so the ON position is reached by a forward or upward motion.
C. so the ON position is reached by a forward or upward motion.
3. 21. A term commonly used when two or more electrical terminals are installed on a single lug of a terminal strip is A. strapping B. piggy backing. C. stacking.
C. stacking.
3. 20. Electrical circuit protection devices are installed primarily to protect the A. Switch B. Units C. wiring
C. wiring
41. What is the principal advantage of the series-wound DC motor a. High starting torque. b. Suitable for constant speed use. c. Low starting torque.
a. High starting torque.
36. Which of the following statements regarding magneto switch circuits is false? a. In the BOTH position, the right and left magneto circuits are grounded. b. In the OFF position, neither the right nor the left magneto circuit is open. c. In the RIGHT position, the right magneto circuit is open and the left magneto circuit is grounded. d. In the LEFT position, the left magneto circuit is open and the right magneto circuit is grounded.
a. In the BOTH position, the right and left magneto circuits are grounded.
Ch14. 4. Why are turbine-engine igniters less susceptible to fouling than reciprocating-engine spark plugs? a. The high-intensity spark cleans the igniter with heat. b. The frequency of the spark is lower for igniters. c. Turbine igniters operate at lower temperatures. d. Turbine fuel does not contain igniter contaminants.
a. The high-intensity spark cleans the igniter with heat.
Ch14. 8. Which statement is correct in regard to the ignition system of a turbojet engine? a. The system is normally deenergized as soon as the engine starts. b. It is a low-voltage, high-amperage system c. It is energized during the starting and warm-up periods only. d. The system generally includes a polar inductor-type magneto.
a. The system is normally deenergized as soon as the engine starts.
4. What is the purpose of a safety gap in some magnetos? a. To discharge the secondary coil's voltage if an open occurs in the secondary circuit b. To ground the magneto when the ignition switch is off c. To keep the magneto from delivering a spark until it reaches its coming-on speed d. To prevent flashover in the distributor
a. To discharge the secondary coil's voltage if an open occurs in the secondary circuit
27. The electrical circuit from the spark plug back to the magneto is completed by a. grounding through the engine structure to the magneto b. grounding through the fuselage to earth. c. grounding through spark plug lead shielding to the magneto. d. a ground wire through the cockpit switch.
a. grounding through the engine structure to the magneto
10. Magneto pole shoes are generally made of a. laminations of high-grade soft iron. b. laminations of high-grade alnico. c. strips of extremely hard steel. d. pieces of high-carbon iron.
a. laminations of high-grade soft iron.
40. If new breaker points are installed in a magneto on an engine, it will be necessary to time a. the magneto internally and the magneto to the engine. b. the breaker points to the No. I cylinder. c. the magneto drive to the engine. d. the distributor gear to the magneto drive
a. the magneto internally and the magneto to the engine.
29. When the ignition switch of a single (reciprocating) engine aircraft is turned to the OFf position, a. the primary circuits of both magnetos are grounded. b. the secondary circuits of both magnetos are opened. c. all circuits are automatically opened. d. the high-tension lead from the battery is grounded.
a. the primary circuits of both magnetos are grounded.
32. The numbers appearing on the ignition distributor block indicate a. the sparking order of the distributor. b. the relation between distributor terminal numbers and cylinder numbers. c. the ratio of the distributor rotor speed to the crankshaft speed. d. the firing order of the engine.
a. the sparking order of the distributor.
7. What is the electrical location of the primary condenser in a high-tension magneto? a. Across the ignition switch b. Across the breaker points c. In series with the breaker points d. Between the ignition switch and the breaker points
b. Across the breaker points
Ch14. 3. In a turbine-engine de capacitor discharge ignition sys-tem, where are the high-voltage pulses formed? a. At the breaker b. At the triggering transformer c. At the rectifier d. At the multilobe cam
b. At the triggering transformer
38. Which of the following would be cause for rejection of a spark plug? a. Carbon fouling of the electrode and insulator b. Cracked insulator tip c. Light gray coloration of the center electrode d. Lead fouling of the electrode and insulator
b. Cracked insulator tip
2. The greatest density of flux lines in the magnetic circuit of a rotating magnet-type magneto occurs when the magnct is in what position? a. The neutral position b. Full alignment with the field shoe faces c. A certain angular displacement beyond the neutral position, referred to as the E-gap angle or position d. The position where the contact points open
b. Full alignment with the field shoe faces
21. Failure of an engine to cease firing after the magneto switch has been tumed off is an indication of a. a grounded magneto lead. b. an open in the low-tension lead to ground. c. a grounded condenser. d. a grounded magneto switch.
b. an open in the low-tension lead to ground.
43. The commutator of a generator a. changes direct current produced in the armature into alternating current as it is taken from the armature. b. changes alternating current produced in the armature into direct current as it is taken from the armature. c. reverses the current in the field coils at the proper time in order to produce direct current.
b. changes alternating current produced in the armature into direct current as it is taken from the armature.
13. In an aircraft ignition system, one of the functions of ine condenser is o a. regulate the flow of current between the primary and secondary coils. b. facilitate a more rapid collapse of the charge in the primary coil. c. stop the flow of magnetic lines of force when the points open. d. act as a safety gap for the secondary coil.
b. facilitate a more rapid collapse of the charge in the primary coil.
42. The pole pieces or shoes used in a DC generator are a part of the a. armature assembly. b. field assembly. c. brush assembly.
b. field assembly.
14. As an aircraft engine's speed is increased, the voltage induced in the primary coil of the magneto a. remains constant. b. increases. c. varies with the setting of the voltage regulator. d. decreases.
b. increases.
30. A spark plug's heat range is the result of its specific design, and therefore of a. the area of the plug exposed to the cooling airstream. b. its ability to transfer heat from the firing end to the cylinder head. c. the area of the plug terminal. d. the heat intensity of the spark.
b. its ability to transfer heat from the firing end to the cylinder head.
25. Magneto breaker points must be timed to open when a, the rotating magnet is positioned a few degrees before neutral. b. the greatest magnetic field stress exists in the magnetic circuit. c. the least magnetic field stress exists in the magnetic circuit. d. the rotating magnet is in the full register position.
b. the greatest magnetic field stress exists in the magnetic circuit.
31. The term "reach," as applied to spark plug design and/or type, indicates a. the length of the center electrode insulation exposed to the flame of combustion. b. the linear distance from the shell gasket seat to the end of the shell skirt. c. the length of the center electrode exposed to the flame of combustion. d. the length of the shielded barrel.
b. the linear distánce from the shell gasket seat to the end of the shell skirt.
22. Alignment of the marks provided for internal timing of a magneto indicates that a. the breaker points are just beginning to close for the No. I cyninder. b. the magneto is in the E-gap position. c. the No. 1 cylinder is at TDC of the compression stroke. d. the distributor gear is correctly aligned with the rotor shaft.
b. the magneto is in the E-gap position.
35. If a spark plug lead becomes grounded, a. the magneto secondary winding will become overloaded and break down. b. the magneto will not be affected. c. the distributor rotor finger will discharge to the next closest electrode within the distrioutor. d. the condenser will break down.
b. the magneto will not be affected.
24. The amount of voltage generated in any magneto secondary coil is determined by the number of windings and by a. the rate of buildup of the magnetic field around the primary coil. b. the rate of collapse of the magnetic field around the primary coil. c. the amount of charge stored by the capacitor. d. the amount of charge released by the capacitor.
b. the rate of collapse of the magnetic field around the primary coil.
1. The E-gap angle is usually defined as the number of degrees between the neutral position of the rotating magnet and the position a. where the contact points close. b. where the contact points open. c. of greatest magnetic flux density. d. at which the secondary current is lowest.
b. where the contact points open.
34. Hot spark plugs are generally used in aircraft power-plants a. with comparatively high compression or high operating temperatures. b. with comparatively low operating temperatures. c. which are loosely baffled. d. which produce high power per cubic inch of dis-placement.
b. with comparatively low operating temperatures.
Ch14. 10. Why do turbine-engine ignition systems require high energy? a. For ignition of the fuel under conditions of high altitude and high temperatures. b. Because the applied voltage is very high. c. For ignition of the fuel under conditions of high altitude and low temperatures. d. Because the applied voltage is very low.
c. For ignition of the fuel under conditions of high altitude and low temperatures.
28. Which of the following will cause the center electrode insulator of ceramic spark plugs to fracture and/or break? a. Improper timing b. Electrical erosion c. Improper gapping procedures d. Excessive magneto voltage
c. Improper gapping procedures
8. In a high-tension ignition system, the current in the magneto secondary winding is a. conducted from the primary winding via the discharge of the condenser. b. conducted from the primary by the counter emf develoned across the condenser. c. Induced when the primary circuit is interrupted. d. induced when the primary circuit discharges via the breaker points.
c. Induced when the primary circuit is interrupted.
39. What will be the result of using an excessively hot spark plug? a. Failure of the engine b. Fouling of the plug c. Preignition d. Burning of the condenser
c. Preignition
12. What component(s) make(s) up the magnetic system of a magneto? a. Pole shoes, pole shoe extensions, and primary coil b. Primary and secondary coils c. Rotating magnet, pole shoes, pole shoe extensions, and coil core d. Rotating magnet
c. Rotating magnet, pole shoes, pole shoe extensions, and coil core
20. What is the purpose of using an impulse coupling with a magneto? a. To absorb impulse vibrations between the magneto and the engine b. To compensate for backlash in the magneto and the c. To produce a momentary high rotational speed of the magneto d. To prevent the magneto speed from fluctuating at high engine speeds
c. To produce a momentary high rotational speed of the magneto
11. Capacitance afterfiring in most modern spark plugs is reduced oy te use or a. massive electrodes. b. fine wire electrodes. c. a built-in resistor in each plug. d. aluminum oxide insulation.
c. a built-in resistor in each plug.
18. The spark is produced in a magneto ignition system when the breaker points are a. beginning to close. b. fully open. c. beginning to open. d. fully closed.
c. beginning to open.
16. A defective primary condenser in a magneto is indicated by a. broken breaker points. b. a fine-grained frosted appearance of the breaker Points c. burned and pitted breaker points. d. weak spark.
c. burned and pitted breaker points.
3. Magneto breaker-point opening relative to the position of the rotating magnet and distributor rotor (internal timing) can be set most accurately a. after magneto-to-engine timing has been completed. b. during the magneto-to-engine timing operation, with subsequent in-service readjustment for wear and pitting. c. during assembly of the magneto before installation on the engine. d. by setting the points roughly at the required clearance before installing the magneto and then making the fine breaker-point adjustment after installation to compensate for wear in the magneto drive train.
c. during assembly of the magneto before installation on the engine.
17. A magneto ignition switch is connected a. in series with the breaker points. b. in series with both the breaker points and the primary condenser. c. parallel to the breaker points. d. in series with the primary condenser and parallel to the breaker point
c. parallel to the breaker points.
Ch14. 5. The constrained-gap igniter plug used in some gas-turbine engines operates at a lower temperature occause a. it projects into the combustion chamber. b. the applied voltage is less. c. the construction is such that the spark occurs beyond the face of the combustion chamber liner. d. it has multiple electrodes to share the voltage arcing
c. the construction is such that the spark occurs beyond the face of the combustion chamber liner.
Ch14. 6. When a turbine-engine igniter plug is removed, in order to eliminate the possibility of the technician receiving a lethal shock, the ignition switch is turned off. In addition to this precaution, a. the ignition switch should be disconnected from the power-supply circuit. b. insulating rubber gloves should be wor. c. the igniter lead should be disconnected from the plug and the center electrode grounded to the engine after the transformer-exciter input lead has been disconnected from the plug and the prescribed waiting period observed. d. the transformer-exciter input lead should be disconnected from the plug and the center electrode grounded to the engine after the igniter lead has been disconnected from the plug and the prescribed waiting period observed.
c. the igniter lead should be disconnected from the plug and the center electrode grounded to the engine after the transformer-exciter input lead has been disconnected from the plug and the prescribed waiting period observed.
15. During internal timing of a magneto, the breaker points begin to open when a. the piston has just passed TDC at the end of the compression stoxe. b. the resultant flux flow is zero. c. the magnet poles are a few degrees beyond the neutral position. d. the magnet poles are fully aligned with the pole shoes
c. the magnet poles are a few degrees beyond the neutral position.
5. When a magneto is being timed internally, the alignment of the timing marks indicates that a. the breaker points are just closing. b. the magnets are in the neutral position. c. the magnets are in the E-gap position. d. the breaker points are open to their widest gap.
c. the magnets are in the E-gap position.
Ch14. 2. How does the ignition system of a gas-turbine engine differ from that of a reciprocating engine? a. One igniter plug is used in each combustion chamber. b. Low-energy igniter plugs are used in place of spark plugs. c. Magneto-to-engine timing is not critical. d. A high-energy spark is required for ignition.
d. A high-energy spark is required for ignition.
23. What is the difference between a low-tension and a high-tension ignition system? a. A low-tension system produces relatively low voltage at the spark plug compared with a high-tension b. A low-tension system does not require high-voltage leads, but a high-tension system requires all leads to transmit high voltage. c. A high-tension system is designed for high-altitude aircraft, whereas a low-tension system is designed for low- to medium-altitude aircraft. d. A low-tension system uses a transformer coil near the spark plugs to boost voltage, whereas a high-tension system has constant voltage from the magneto to the spark plugs.
d. A low-tension system uses a transformer coil near the spark plugs to boost voltage, whereas a high-tension system has constant voltage from the magneto to the spark plugs.
6. When a magneto is being timed internally, the breaker points begin to open when the rotating magnet is a. in the neutral position. b. fully aligned with the pole shoes. c. a few degrees past full alignment with the pole shoes d. a few degrees past the neutral position.
d. a few degrees past the neutral position.
Ch14. 9. The type of ignition system used on most turbine air- crat cheines is al a. nigh-resistance sysicm. b. magneto system. C. low-tension system. d. capacitor-discharge system.
d. capacitor-discharge system.
Ch14. 1. The capacitor-type ignition system is used almost universally on turbine engines because of its high voltage and a. low amperage. b. long life. c. low temperature range. d. high heat intensity.
d. high heat intensity.
33. Compensated timing provides for the firing of the cylinders a. at the position of crankshaft travel that provides the balance between the inertia of the reciprocating mass and the force that results from compressing the fuel-air charge. b. at the piston position which produces peak compression regardless of the degree of crankshaft travel required to obtain that position. c. an equal number of degrees of crankshaft travel apart regardless of variations in piston position caused by articulation of the connecting rod assembly. d. in relationship to piston position regardless of variations in crankshaft travel required to obtain that position.
d. in relationship to piston position regardless of variations in crankshaft travel required to obtain that position.
37. A spark plug is fouled when a. its gap is too small. b. its magneto wire is not connected. c. it causes preignition. d. its spark grounds without jumping electrodes.
d. its spark grounds without jumping electrodes.
9. When a "Shower of Sparks" ignition system is activated at an engine start, a spark plug fires a. as soon as the retard breaker points close. b. as soon as the advance breaker points open. c. only while both the retard and advance breaker points are closed. d. only while both the retard and advance breaker points are open.
d. only while both the retard and advance breaker points are open.
19. Shielding is used on spark plug and ignition wires to a. prevent leakage of current which results in a weak spark. b. protect the wires from short circuits as a result of chafing and rubbing. c. protect the wires from oil and grease. d. prevent interference with radio reception.
d. prevent interference with radio reception.
26. In a low-tension ignition system, each spark plug requires an individual a. condenser. b. cam assembly. c. breaker assembly. d. secondary coil.
d. secondary coil.
Ch14. 7. Igniter plugs used in turbine engines are subjected to much higher voltage than reciprocating-engine spark plugs, and yet their service life is longer. This is because a. they operate at much lower temperatures. b. their electrode gap is much smaller. c. they are not placed directly in the combustion area. d. they are not required to operate continuously.
d. they are not required to operate continuously.
