Electrical system Part1

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.

If the positive field lead between a generator and a generator control panel breaks and is shorted while the engine is running, a voltmeter connected to generator output would indicate. zero voltage. residual voltage. normal voltage.

Which type of DC generator is not used as an airplane generator?. Externally grounded. Series wound. Compound wound.

To help minimize radio interference a capacitor will largely eliminate and provide a steady direct current if the capacitor is connected to the generator in. parallel. series. series/parallel.

The pole pieces or shoes used in a DC generator are a part of the. armature assembly. field assembly. brush assembly.

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.

When DC generators are operated in parallel to supply power for a single load, their controls include an equalizer circuit to assure that all generators share the load equally. The equalizer circuit operates by. increasing the output of the low generator to equal the output of the high generator. decreasing the output of the high generator to equal the output of the low generator. increasing the output of the low generator and decreasing the output of the high generator until they are equal.

Microswitches are used primarily as limit switches to. limit generator output. control electrical units automatically. prevent overcharging of a battery.

A certain switch is described as a single-pole, double-throw (SPDT) switch. The throw of a switch indicates the number of. circuits each pole can complete through the switch. terminals at which current can enter or leave the switch. places at which the operating device (toggle, plunger, etc.) will come to rest and at the same time open or close a circuit.

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.

Aircraft electrical junction boxes located in a fire zone are usually constructed of. aluminum sheets. carbon steel. stainless steel.

The major advantages of alternating current (AC) over direct current (DC) is the fact that its current and voltage can easily be increased or decreased. by means of a inverter. by means of a rectifier. by means of a transformer.

If it is necessary to use an electrical connector where it may be exposed to moisture, the mechanic should. coat the connector with grease. use a special moisture-proof type. spray the connector with varnish or zinc-chromate.

When handling a high voltage capacitor in an electrical circuit, be sure it. has a full charge before removing it from the circuit. has at least a residual charge before removing it from the circuit. is fully discharged before removing it from the circuit.

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.

The poles of a generator are laminated to. reduce flux losses. increase flux concentration. reduce eddy current losses.

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.

Grounding is electrically connecting a conductive object to the primary structure. One purpose of grounding is to. prevent current return paths. allow static charge accumulation. prevent development of radio frequency potentials.

(Refer to Figure 18.) Which of the batteries are connected together incorrectly?. 1. 2. 3.

When necessary during operation, CSD disconnect is usually accomplished by. a switch in the cockpit. circuit breaker activation. a shear section in the input shaft.

During inspection of an anticollision light installation for condition and proper operation, it should be determined that. electrical or mechanical interconnections are provided so that the anticollision light will operate at all times that the position light switch is in the ON position. an appropriately rated fuse is in position at the light to protect the connecting wiring against electrical faults. the anticollision light can be operated independently of the position lights.

What is required when operating two aircraft AC generators in parallel?. Amperes and frequency must both be equal. Frequency and voltage must both be equal. Amperes and voltage must both be equal.

How should a voltmeter be connected?. In series with the source. In parallel with the load. In series with the load.

The strength of the core of an electromagnet depends upon the material from which it is constructed and which of the following?. The number of turns of wire in the coil and the applied voltage. The number of turns of wire in the coil and the amount of current (amperes) passing through the coil. The size (cross section) and the number of turns of wire in the coil and the applied voltage.

What is the frequency of an alternator dependent upon?. Voltage. RPM. Current.

What is the maximum amount of time a circuit can be in operation and still be an intermittent duty circuit?. Three minutes. Two minutes. One minute.

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

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. opposite the normal direction and through the shunt field in the normal direction.

In aircraft electrical systems, automatic reset circuit breakers. should not be used as circuit protective devices. are useful where only temporary overloads are normally encountered. must be used in all circuits essential to safe operation of the aircraft.

What is the advantage of a current limiter?. It breaks circuit quickly. It can be reset easily. It will take overload for a short period.

During ground operation, aircraft generator cooling is usually accomplished by. auxiliary air cooled through an air-fuel heat exchanger. an integral fan. an external motor-driven fan.

What is the voltage drop for a No. 18 copper wire 50 feet long to carry 12.5 amperes, continuous operation? Use the formula VD = RLA VD = Voltage drop R = Resistance per ft = .00644 L = Length of wire A = Amperes. 1/2V. 1V. 4V.

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. varying current flow to generator field coil.

What kind of switch should the aviation mechanic install in a single wire circuit that requires the switch to be manually held in the ON position?. Single-pole, single-throw (SPST), two-position normally open (NO). Single-pole, single-throw (SPST), single-position. Single-pole, double-throw (SPDT), single-position normally open (NO).

A battery-generator system provides direct current. On installations requiring alternating current from the battery-generator system, it is necessary to have. a transformer. an inverter. a variable resistor between the battery and generator.

What is a cause of generator brush arcing?. Seating brushes with No. 000 sandpaper. Carbon dust particles. Low spring tension.

What is the principal advantage of the series-wound DC motor?. High starting torque. Suitable for constant speed use. Low starting torque.

What is a method used for restoring generator field residual magnetism?. Flash the fields. Reseat the brushes. Energize the armature.

If any one generator in a 24-volt DC system shows low voltage, the most likely cause is. an out-of-adjustment voltage regulator. shorted or grounded wiring. a defective reverse current cutout relay.

Which of the following factors must be taken into consideration when determining the wire size to use for an aircraft installation?. Allowable power loss, permissible voltage drop, current carrying capability of the conductor, type of load. Mechanical strength, allowable power loss, resistance of current return path through the aircraft structure, type of load. Allowable power loss, resistance of current return path through the aircraft structure, type of load.

The circuit breaker in the instrument lighting system protects the. lights from too much current. wiring from too much current. wiring from too much voltage.

An aircraft electrical circuit control relay is. an electronically operated switch. a device which converts electrical energy to kinetic energy. any conductor which receives electrical energy and passes it on with little or no resistance.

What is the ratio of turns between the primary coil winding and the secondary coil winding of a transformer designed to triple its input voltage?. Primary will have one-third as many turns as its secondary. Primary will have twice as many turns as its secondary. Primary will have three times as many turns as its secondary.

Which of the following are the major parts of a DC motor?. Armature assembly, field assembly, brush assembly, and end frame. Field assembly, brush assembly, commutator, and pole piece. Brush assembly, pole piece, rheostat, and end frame.

A CSD unit that is disconnected in flight, due to a malfunction such as overtemperature, may be reconnected. automatically if the temperature falls back into the normal operating range. manually by the flightcrew. only on the ground by maintenance personnel.