Alternators

Which type of stator connection winding is not suitable for aircraft use?

"Delta" connected

How are the stator leads connected together for aircraft use?

"Wye" connected.

What would be the output voltage of an alternator with the alternator switch and circuit breaker on, if the engine has been hand propped tp start because the battery was removed?

0 (zero) volts

What would be the voltage output of a 12 volt alternator having an open field circuit?

0 volts

How many electrical degrees apart are the three stator windings of the 14/28 volt alternator?

120 degrees

The purpose of a rectifier in an electrical system is to change:

Alternating current into direct current

The difference between a DC generator and a alternator is:

Alternator has a rotating field, the generator has a stationary field

One of the advantages of an alternator over a generator system is.

Alternator has a stationary armature

The process of increasing and decreasing field current is performed by what type of newer (Solid state)

An ACU (Alternator Control Unit)

A negative diode is identified by what markings

Black or green dot or part number

How is the output voltage of a DC alternator controlled?

By controlling field current through the rotor

How is a 12 volt alternator field excited?

By passing direct current through the rotor assembly?

The solid state full wave rectifier unit used in the alternator system performs what function?

Changes the alternating current produced in the stator of a 14 volt alternator to DC.

The diodes as used in the alternator system take the place of what component in the generator system?

Commutator and brushes

Which of the following is NOT a use for diodes in an electrical circuit.

Current limiters

Where is the voltage generated in an alternator?

In the stator

Which of the following is a correct test procedure if a alternator has zero voltage output?

Jump battery positive (+) terminal to "F" terminal

What would be the result if a 12 volt alternator's direction of rotation was reversed?

Normal operation with a possible loss of cooling

What function other than rectification does the six diodes perform for the alternator system?

Prevent the battery from discharging through the stator windings.

What is one of the functions of the field relay in an alternator system?

Prevents battery from draining current thru the field circuit when the system is secured.

The alternator rectifier unit performs which of the following functions?

Prevents reverse current through the stator

A positive diode is identified by what markings?

Red dot or part number.

Which of the following would be considered an advantage of a 12 volt alternator?

Requires very little maintenance High output at low RPM -Both answers are correct

What type of bearings are used in the alternator slip ring end housing?

Roller (needle)

What type of bearings is used in the alternator drive end frame?

Sealed ball bearing

What is the purpose of the capacitor on terminal #4 of the vibrating point type alternator control unit used for the 14 volt alternator?

Smooths out output voltage

The alternating current produced in the stator of a alternator, is changed to DC by the use of what?

Solid state full wave rectifier unit.

The alternator VR works on what principle

Spring tension versus electromagnetic force

What may be the cause of damage to the diodes.

The battery leads were connected backwards

Why are the brushes of a DC alternator more efficient and have a longer service life than those of a DC generator

The brushes pass only field current

What would be the result in alternator system if the battery leads are connected with reverse polarity?

The diodes would probably be damaged

The stator of an alternator is excited by what?

The field assembly

What prevents voltage from dropping to zero when the lower VR points are open?

The field resistor

Why is an RCCR not required in a 14 volt alternator system?

The output is rectified by diodes which also prevent reverse current.

The field induces voltage into what part of an alternator

The stator assembly

High voltage at high RPM may be the result of which of the following?

The upper points of the VR are open to ground

Which of the following prevents overcharging the battery in a alternator system?

The voltage regulator

What is the purpose of the rotor in an alternator

To induce AC into the stator

What is the purpose of the rotor in an alternator?

To produce a DC magnetic field to induce an ac voltage in the three phase stator.

What is the purpose of the slip rings?

Transfer DC current to the rotor (field)

The field gets its current through the field resistor:

When the alternator voltage regulator points are open.

If the Upper points if the VR vibrating regulator are stuck to the stationary center point, what will be the effect on voltage output?

Zero Voltage