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F. Engine electrical
Engine electrical 6
Question | Answer |
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When the engine is operating, what does an ammeter/loadmeter indicate when connected to: 1. Battery positive lead? 2. Generator output lead? | When connected to the battery positive lead, the ammeter indicates whether the battery is charging or discharging. When connected to the generator output lead, it indicates the current produced by the generator, or electrical system load. |
What is done to ensure that each generator shares the load in a multiple generator system? | The generators are paralleled. |
Where would you find generator rating and performance data? | On the data plate attached to the generator. |
How is the voltage of a DC generator controlled? | By varying the field current strength. |
What is the most common type of alternator used in most aircraft AC-DC systems? | The three phase alternator. |
How does a voltage regulator control the voltage of an alternator? | By regulating the voltage output of the DC exciter. |
What does the speed of rotation and number of poles of an alternator determine? | The frequency of the alternator output. |
What are some of the methods used to maintain 400 hertz alternator output frequency on large turbojet or turbofan engines? (3) | Constant speed drives, integrated drive generators, and variable- speed constant frequency power systems. |
Name the major parts of a DC motor. (4) | The armature, field, brushes and frame assembly. |
Name the components of a direct cranking electric starter system.(4) | An electric motor, reducing gears, and an automatic engaging and disengaging mechanism. |
Name the three types of DC motors. | Series, shunt and compound. |
What type of DC motor is commonly used for a reciprocating engine starter and why? | A series wound motor is commonly used because it has a high starting torque under heavy loads conditions. |
What are the operating modes of a turbine engine starter generator? (2) | It operates first as a starter, then as a generator once the engine is running. |
What is a possible indication when a starter drags? | A dirty or worn starter commutator. |
Where would wire with high temperature insulation material be used? | When they run close to high temperature areas such as exhaust stacks or heating ducts. |
What is the size standard for electrical wire used in US manufactured aircraft? | The American wire gauge. |
How are wire sizes represented? | By a numbered gauge size. The smaller wires are represented by larger numbers. The smallest size wire normally used in aircraft is 22 gauge. |
What is the maximum slack allowed between the supports of a single wire or bundle installation? | Not over .5 inches. |
Why are wires bonded on powerplant installations? | To provide a current return path for electrical accessories, and to prevent static discharge. |