Term
| Each of the three waveforms at the at the outputs of a three phase alternator will be: |
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Definition
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Term
| How many diodes are are required for full wave rectification in a three phase alternator |
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Definition
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Term
| Which of the following is a result of rotating the field in an alternator? |
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Definition
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Term
| During alternator serviceing, the technician measures 10,000(ohms) between one stator lead and the two other stator leads of an alternator. The resistance between the two other leads measures 10(ohms). What does this mean? |
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Definition
| A stator winding is partly open |
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Term
T or F
Diodes can be measured easily in-circuit using an ohmmeter. |
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Definition
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Term
| Why will a brushless alternator (ac-generator) contain diodes? |
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Definition
| to create dc for the main generator field. |
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Term
| Why do alternators (ac-generators) aboard aircraft using AC systems require a constant speed drive unit? |
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Definition
| to insure proper output frequency |
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Term
| How is speed regulated within a constant speed drive unit? |
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Definition
| using a fly-weight type governor |
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Term
| What unit contains both the constant speed drive unit and the ac generator? |
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Definition
| the integrated drive generator |
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Term
| Which of the following are advantages of using ac electrical systems on board large aircraft? |
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Definition
Decreased weight
More efficient transfer of energy
(a and b above are correct) |
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Term
T or F
Alternators will not self-start, the field must be energized from an external source. |
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Definition
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Term
| What is the purpose of a zener diode? |
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Definition
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Term
T or F
The carbon pile works like a variable resistor. |
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Definition
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Term
| Which statement is true regarding regulation? |
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Definition
| controlling field current will control voltage output |
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Term
| An airplane has an ammeter that has a scale from 0 to +60. Where would that meter be located? |
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Definition
| between the generator and the battery |
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Term
| What is a Current Transformer? How does it work? |
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Definition
Donut shaped inductive pick ups.
Lead of an AC generator passes through the pick up and induces a voltage in the CT that is proportional to the current flowing in the lead. |
|
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Term
| What is a TRU? What does it do? |
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Definition
Transformer / Rectifiers units
Converts AC to DC |
|
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Term
| What are two different ways to cool CSD oil? |
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Definition
1. fuel heater/oil cooler
2. bypass air |
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Term
| What are three functions of a GCU? |
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Definition
Voltage Regulation
Reverse current /Differential voltage protection
Reverse polarity
Anti-cycle
Latching Field Relay Control
Flash and start control
Self Test |
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Term
T or F
DC Alternators require a reverse current relay. |
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Definition
|
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Term
| How can the direction of rotation of a dc electric motor be changed? |
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Definition
| Reverse connections to either field or armature windings |
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Term
| If a generator is equipped with a vibrator-type voltage regulator, the actual time the voltage regulator points remain open |
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Definition
| depends on the load carried by the generator |
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Term
| The only practical method of maintaining a constant voltage output from an aircraft generator under varying conditions of speed and load is to vary the |
|
Definition
| strength of the magnetic field |
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Term
| The pole pieces or shoes used in a dc generator are a part of the |
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Definition
|
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Term
| 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 |
|
Definition
| opposite the normal direction and through the shunt field in the normal direction |
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Term
| A series-wound dc electric motor will normally require |
|
Definition
| more current at low RPM than at high RPM |
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Term
| The commutator of a generator |
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Definition
| changes alternating current produced in the armature into direct current as it is taken from the armature |
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Term
| Which of the following is not one of the purposes of interpoles in a generator? |
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Definition
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Term
| The poles of a generator are laminated to |
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Definition
| reduce eddy current losses |
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Term
| 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 |
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Definition
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Term
| Residual voltage is a result of magnetism in the |
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Definition
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Term
| If the points in a vibrator type voltage regulator stick in the closed position while the generator is operating, what will be the probable result? |
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Definition
| Generator output voltage will decrease |
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Term
| In a carbon pile regulator system, the output of the generator is regulated by |
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Definition
| adjusting pressure on the carbon stack |
|
|
Term
| Which statement is true regarding regulation? |
|
Definition
| controlling field current will control voltage output |
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|
Term
| What is the purpose of a growler test? |
|
Definition
| Check for shorts in the armature |
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Term
| With respect to a DC Generator, what is armature reaction and how does it affect generator operation? |
|
Definition
distortion or bending of the lines of magnetic flux between the pole of the generator
-arcing
-generator output reduced |
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Term
| What is meant by flashing the field? Why is it done? |
|
Definition
| restore the residual magnetism by momentarily passing current through the field coils in the same direction that it normally flows. |
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|
Term
| How does a voltage regulator control generator output? |
|
Definition
| A rheostat decreases/increases resistance in the field circuit into the field coils |
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Term
| What is the purpose of the reverse current relay? |
|
Definition
| prevent battery discharge through the generator armature when the generator voltage falls below that of the battery |
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Term
| What are 2 ways to compensate for armature reaction? |
|
Definition
-interpoles
-shifting the brushes to the plane of commutation |
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Term
| The correct way to connect a test voltmeter in a circuit is |
|
Definition
|
|
Term
| Through which material will magnetic lines of force pass the most readily? |
|
Definition
|
|
Term
| What unit is used to express electrical power? |
|
Definition
|
|
Term
| Which is correct concerning a parallel circuit? |
|
Definition
| Total resistance will be smaller than the smallest resistor |
|
|
Term
| The ability of a material to conduct magnetic lines of flux is known as _____ |
|
Definition
|
|
Term
| The ____ of a material refers to its ability to retain magnetism after a magnetic force is applied. |
|
Definition
|
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Term
| Name 2 things that happen when current flows in a conductor. |
|
Definition
|
|
Term
| List 3 methods for electricity to be produced |
|
Definition
|
|
Term
| Explain Kirchoffs Law of Voltage |
|
Definition
| The sum of all the voltage drops in a circuit is equal to the sum of the voltage applied |
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|
Term
| Explain Kirchoffs Law of Current |
|
Definition
| In a series circuit, the current flow is always the same |
|
|
Term
| List three factors that determine the resistance of a conductor |
|
Definition
|
|
Term
| What is the difference between a rheostat and a potentiometer? |
|
Definition
|
|
Term
| How do changes in frequency affect an AC circuit? |
|
Definition
| changing the rated frequency that an AC circuit can be used |
|
|
Term
| What factors affect impedance in an AC circuit |
|
Definition
frequency
wire capacitance
distance (length of wire) |
|
|
Term
| If frequency increases, ____ ____ will increase, and ____ ____ will decrease. |
|
Definition
inductive reactance
capacitance reactance |
|
|
Term
| When current flows in the coils of a generator armature, a magnetic field is set up within the armature that is at right angles to the generator field. What is this called? |
|
Definition
|
|
Term
| What supports armature bearings in a generator? |
|
Definition
|
|
Term
| How is current induced in the windings of a DC generator? |
|
Definition
|
|
Term
| Without filtering, what type of output is produced by a DC generator? |
|
Definition
|
|
Term
| What controls the output power of a DC generator? |
|
Definition
|
|
Term
| Where is the field winding grounded in “A” and “B circuit” generators? |
|
Definition
|
|
Term
| Which generator brush(es) will be insulated? |
|
Definition
|
|
Term
| What materials are used in brushes? |
|
Definition
|
|
Term
| When should brushes be replaced? |
|
Definition
|
|
Term
| How is residual magnetism used in DC generators? |
|
Definition
|
|
Term
| What type of field winding is used in aircraft generators? |
|
Definition
Series (for starting)
Shunt (for generating) |
|
|
Term
| Why are interpole windings integrated into a generator? |
|
Definition
Help maintain a constant neutral plane
(counter armature reaction) |
|
|
Term
| How are DC alternators and generators regulated? |
|
Definition
|
|
Term
| When the contacts of a vibrating regulator are closed, what happens? |
|
Definition
shorts the field rheostat
terminal voltage starts to rise |
|
|
Term
| How does a carbon pile regulator work? |
|
Definition
| relies on the resistance of carbon disks arranged in a pile or stack |
|
|
Term
| How are over current conditions prevented in a DC generator system? |
|
Definition
| carbon pile current limiter |
|
|
Term
| How is DC created in a DC alternator? |
|
Definition
| Alternators create AC which is then converted to DC before entering the system |
|
|
Term
| How is the transistor(s) used in a solid state regulator? |
|
Definition
|
|
Term
What should you measure between the rotor slip rings on an alternator?
What symptoms would shorts and opens show? |
|
Definition
|
|
Term
What should you measure between the rotor slip rings and the rotor shaft on an alternator?
What symptoms would shorts and opens show? |
|
Definition
| resistence (should be infinite) |
|
|
Term
What should you measure between the stator leads on an alternator?
What symptoms would shorts and opens show? |
|
Definition
|
|
Term
|
Definition
must remove to test.
test resistance but only one direction |
|
|
Term
| Why use an ac electrical systems on board large aircraft? |
|
Definition
| high power to weight ratio |
|
|
Term
| How are switches de-rated? (Specifics) |
|
Definition
| by multiplying the amperage by the factor determined |
|
|
Term
| What are the spare requirements for fuses? |
|
Definition
|
|
Term
| What is the difference between a fuse and a current limiter? |
|
Definition
| current limiters protect entire bus bars against over current. fuses are used for smaller loads |
|
|
Term
| Name the two different types of circuit breakers? |
|
Definition
| those that open due to excessive heat and those that open due to magnetic field |
|
|
Term
| What does trip free mean? |
|
Definition
|
|
Term
| How do you reverse a DC motor? |
|
Definition
| Change the current through the field or the armature, but not both. |
|
|
Term
| What causes the current and power to lower as the motor speeds up? |
|
Definition
|
|
Term
Name 4 types of tachometers
How does each work? |
|
Definition
| mechanical-flyweights, magnetic-magnet inside drag cup, electric- tach generator, electronic- electric polses |
|
|
Term
Name three types of pressure indicating systems
What is a possible use of each |
|
Definition
| burdon tube, diaphragm, pressure capsule |
|
|
Term
| What are some different ways for indicating power setting in an aircraft? |
|
Definition
|
|
Term
Describe how a resistance type temperature indicating system works.
Name two different types |
|
Definition
ratiometer- decreases resistance as heat increases.
thermocouple- creates voltage when heated |
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Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| SERVICING - ROUTINE MAINTENANCE |
|
|
Term
|
Definition
| STANDARD PRACTICES - AIRFRAME |
|
|
Term
|
Definition
|
|
Term
|
Definition
| ENGINE - FUEL AND CONTROL |
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Term
|
Definition
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