OPERATION

OPERATION

1. AIRCRAFT PRIMARY AC POWER SOURCES

   • Primary power sources include main generators, inverters, and transformers. You must have a basic understanding of the components of these electrical systems and power distribution systems in order to maintain them in proper operating condition.

2. AC GENERATORS

   • Alternating current (ac) generators supply the electrical energy for operating aircraft avionics equipment. A generator is a machine that converts mechanical energy into electrical energy by electromagnetic induction.
   • Los sistemas de energía ac resultan en un mejor diseño y uso de equipo que los equipos electrónicos más antiguos accionados por corriente continua (dc), que tienen inversores para la alimentación de CA y dinamizadores para suministrar potencia de CC de mayor voltaje. Estos componentes son muy pesados ​​en comparación con su salidas de potencia relativa. No son confiables y aumentar los costos de mantenimiento y el tiempo.
   • En el día de hoy aeronave, el mismo equipo con motor ac obtiene varios voltajes de ca y potencia de cc mediante el uso de simples transformadores y transformadores-rectificadores. Estos componentes son livianos, simples y confiables. Los aviones navales modernos usan el trifásico, 120- / 208-voltios, 400-hertz (Hz) sistema de alimentación de CA
   • Types of Ac Generators
     • Controlling the strength of the magnetic field regulates the voltage.
     • The stator (stationary armature winding) provides the ac output.
     • The ac generator field (rotor) is a rotating magnetic field with fixed polarity
     • Regulating the rpm of the rotating magnetic field controls the voltage frequency.

3. generador de corriente alterna Consiste en un generador de CA y un pequeño generador de excitación de CC como una unidad.

4. INVERTERS

   • Inverters consist of a speed-governed dc motor, an armature and brush assembly, and a permanent magnet inductor-type ac generator in one unit. The armature and the permanent magnetic rotor mount on a common shaft.
   • Inverters are an emergency source of ac power when normal ac power fails. The backup system of the F/A-18 aircraft is an example of this type. The standby attitude indicator receives power from the right 115-volt ac bus. If the aircraft’s generators fail to supply power to this bus, the standby attitude indicator receives power from an inverter. Because of a wide variety of inverters in use on aircraft, only one is discussed in this NRTC.

5. TRANSFORMERS

   • A transformer, by itself, is not a true electrical power source. A true electrical power source can produce electrical energy from another type of energy, such as chemical or mechanical. Transformers take electrical energy in the form of an ac voltage and convert it to a different usable ac voltage
   • Transformer-Rectifiers
     • Ac-powered equipment is more efficient than the larger, heavier dc-powered equipment. Therefore, ac generators now power naval aircraft; but dc power is needed for lighting and for controlling ac-powered equipment. The most common device now used to provide the necessary dc voltage is the transformer-rectifier (TR)
   • Autotransformers
     • The autotransformer is like an ordinary transformer, except that it has one winding that is common to both primary and secondary windings. Within the limits of its application, autotransformers offer savings in both size and cost over conventional units

6. ELECTRONIC POWER SUPPLIES

   • are for a 120-/208-volt, three-phase, four-wire, 400-Hz electrical power input. Autotransformers T4, T5, and T6 produce the majority of the output voltages. The autotransformers have taps from each transformer winding at the proper position to produce the required voltage. Under fairly constant load conditions, no further voltage regulation is necessary. Full-wave rectifiers
     • In high performance aircraft, avionics systems help the pilot communicate, navigate, or fire missiles. Other systems, such as radar and autopilot (AFCS), ease the pilot’s workload. Each of these systems requires precision voltage inputs for proper operation

7. EMERGENCY/BACKUP POWER SOURCES

   • Los aviones navales tienen respaldo (emergencia) eléctrico poder si las fuentes primarias de energía eléctrica fallan. los varias formas de suministrar este poder de emergencia son baterías de almacenamiento de aeronaves, unidades de potencia auxiliar y generadores impulsados por motor hidráulico.
     • Batteries
       • The most common aircraft batteries used today are lead-acid and nickel-cadmium batteries. These batteries have a color-coded case for ease of identification, with red for lead-acid and blue for nickel-cadmium.
       • Most wet-cell batteries emit some type of gas when being charged or discharged. This is especially true of lead-acid batteries and, to a lesser degree, the nickel-cadmium batteries. For this reason, a vent in the filler plug allows each cell to vent gas and moisture into the void of the battery. Allowing the moisture to stand in the battery void could cause shorting of the cells and corrosion, so openings at each end of the battery provide ventilation of the void area

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