Airframe electrical ch7:A

The open circuit voltage of a lead acid cell is approximately ____ volts.

2.1

Spilled electrolyte from a lead acid battery should be neutralized with ____ ____ and rinsed with ____.

Baking soda, water

Spilled nickel cadmium electrolyte can be neutralized with ____ ____ or ____.

Boric acid, vinegar

The two methods for charging a battery are the constant ____ method and the constant ____ method. Aircraft generating systems is the constant ____ method.

Current, voltage; voltage

Varying the ____ current controls generator output.

Field

The magnetizing force inside a generator is produced by an electromagnet called a ____ coil and a core called the ____ ____ or ____.

Field; field poles , shoes

Residual magnetism may be restored to a generator by ____ the field.

Flashing (polarizing)

If it becomes necessary to dilute acid to make electrolyte, it is extremely important that you always add the ____ to the ____ and never the other way around.

Acid, water

Modern jet aircraft typically use an ____ cooled ____ alternator.

Air, brushless

Battery capacity is measured in ____ ____.

Ampere hours

The coil of wire in a generator where the current is induced is called the ____.

Armature

The specific gravity of a lead acid battery checked with a ____.

Hydrometer

Some generators use ____ to counter the effect of armature reaction.

Interpoles

A reverse current cutout relay ____ necessary with a DC alternator.

Is not

The specific gravity of the electrolyte in a nickel cadmium battery ____ a measure of the state of charge of the battery.

Is not

Large aircraft use AC alternators because they can produce a ____ amount of power and are ____ in weight.

Large, light

The most commonly used aircraft batteries are the ____ ____ battery and the ____ ____ battery.

Lead acid, Nicole cadmium

Nickel cadmium batteries have a ____ internal resistance.

Low

The position where the plane of two opposite coils is perpendicular to the magnetic field of the generator is called the ____ plane.

Neutral

Each brush is connected to the external circuit by a flexible braided copper ____.

Pigtail

In any generator, current will flow whenever there is ____ motion between the wire coil and yhe magnetic field.

Relative

Solid state voltage regulators are usually ____ if the fail.

Replaced

DC generators employ a ____ ____ relay between the generator output terminal and the bus to prevent the battery from discharging through the generator.

Reverse cutout

The principle parts of an alternator are: a,b,c,d

Rotor, stator, rectifier, brush assembly

____ wound generators are not used in aircraft because of poor voltage regulator characteristics.

Series

Generators may be constructed in one of three ways. The may be:

Series, shunt, compound

The alternating current produced in a DC alternator is changed into direct current with a ____ rectifier.

Solids state

The state of charge of a lead acid battery is determined by measuring the ____ ____ of the electrolyte.

Specific gravity

The principle difference between a DC generator and a DC alternator is that the magnetic field is ____ in a generator and ____ in an alternator.

Stationary; moving

The strength of the induced current depends on the ____ of the magnetic field and the ____ at which the lines of flux are cut.

Strength, speed

Batteries must be kept ____ and the terminals must be kept ____ and free of ____.

Clean, tight, corrosion

The specific gravity of a discharged lead acid battery is about ____.

1.150

The specific gravity of a fully charged lead acid battery should be between ____ and ____ at 80 deg. Fahrenheit (27 deg. Celsius)

1.275, 1.300

In order to charge a 25 volt battery, the alternator must produce about ____ volts, and for a 12 volt battery, about ____ volts.

28, 14

Alternators used in large aircraft generally supply ____ hertz, ____ phase alternating current.

400, 3

The standard rating used to specify battery capacity is the ____ ____ rating.

5 hour discharge

The two functions of an aircraft generating system are to:

A. Carry most of the electrical loads B. Charge the battery

The field frame of a generator has two primary functions. They are to:

A. Complete the magnetic circuit B. Provide mechanical support for the other parts

What does each of the three digits represent in the left hand rule for generator A. First finger B. Middle finger C. Thumb

A. Direction of magnetic field (north/south) B. Direction of induced EMF (voltage) C. Direction conductor moves through the magnetic field

The principle parts of small aircraft DC genre for are the: a,b,c,d

A.field frame B. Rotating armature C. Commutator D. Brush assembly

The distortion of the magnetic field between the generator poles caused by the magnetic field created by the armature is called ____ ____.

Armature reaction

Corrosion and deposits can be removed from a lead acid battery or battery box by scrubbing with a soft ____ ____ and a solution of ____ ____ and water.

Bristle brush, sodium bicarbonate (baking soda)

Current is transferred from the rotating commutator to stationary ____.

Brushes

Brushes are made of high grade ____ to prevent undue wear on the ____ yet still have a reasonable service life.

Carbon, commutator

It is extremely important that nickel cadmium and lead acid batteries be serviced in separate areas because the electrolytes are ____ ____ and their fumes will ____ each other.

Chemically opposite, contaminate

The speed at which a generator begins to produce its rated voltage is called the ____ ____ speed and is usually about ____ RPM.

Coming in, 1500

The device that converts the AC current produced in the armature into DC current is called the ____.

Commutator

On jet aircraft a ____ ____ ____ unit is used between the engine and the alternator to assure a constant frequency output.

Constant speed drive

The three relays contained in a three unit voltage regulator are:

Current limiter, reverse current cutout, voltage regulator

Compound wound generators combine features of both series and shunt wound generators and may be one of three types:

Flat, under, or over compounded

The only way to determine the actual condition of a nickel cadmium battery is to ____ ____ it, then discharge it at a specified rate to measure its ____ ____ capacity.

Fully charge (deep cycle), ampere-hour

A variety of tests can be performed on DC generator and motor armatures with a specially designed test unit called a ____.

Growler

Care should be taken to avoid getting any baking soda in the cells of lead acid battery because baking soda ____ the electrolyte.

Neutralizes

Carbon brushes, riding on smooth ____ ____ carry the field current from the voltage regulator to the alternator rotor.

Slip rings

To minimize the possibility of "thermal runway," aircraft that are equipped with nickel cadmium batteries will have a battery ____ warning system installed.

Temperature (over temp)

A ____ phase alternator is used for almost all aircraft applications.

Three

If one lead from each wining of a three phase alternator is connected to a common point, the stator is ____ connected and if the phases are connected end to end the stator is ____ connected.

Y, delta