Aircraft Batteries
This type of battery is susceptible to thermal runaway.
What is a nicad battery?
Amps, at rated voltage.
How are generators rated?
This has the advantage of smoother current, smaller wires, and lower current needs.
What is three-phase AC power?
How many generated AC power sources does a large 2-engine transport aircraft have, generally?
Three. One on each engine and one on the APU.
This device eliminates arcing between brushes and brush guides.
What is a brush pigtail?
This type of winding is triangle shaped.
What is a delta winding?
What is the definition of rectifying?
Turning AC current into DC current.
These are the units of a 3 unit generator regulator.
What is overvoltage protection, current limiter, reverse current protection
This tool enables to check for a shorted armature?
What is a growler?
The pole pieces and shoes belong to this part of a generator.
These are the three ways a generator can be wound.
What is series, shunt, or compound?
This law states that relative motion between a wire and a magnetic field generates an electromotive force and a flow of current in a closed circuit.
What is Faraday's Law?
This feature reduces eddy current losses in generators.
What are laminated generator poles?
This is the component that allows alternators convert AC to DC.
What are diodes?
What is the definition of inverting?
turning DC current into AC current.
This is a type of variable resistance voltage regulator used in some older aircraft.
What is a carbon pile voltage regulator?
This is high resistance situation where a conductor cannot carry current to its expected destination.
What is an open?
This could cause the deterioration of lead acid and nicad batteries.
What is charging both types of batteries in the same room?
This property is dependent on the following factors: The type of material, rhe number of turns of wire in the coil and the amount of current passing through the coil.
What is the strength of an electromagnetic field?
This is why generators on some aircraft are geared to turn faster than the engines.
Because at idle engine speed the generators won't turn fast enough.
This method enables you to increase electricity without relative motion between field and conductor
What is changing the strength of the magnetic field?
This component consumes power and contains an armature assembly, field assembly, brush assembly and end frame.
What is a DC motor?
Why don't alternators use reverse current relays?
Because the diodes will not allow current to flow through them backwards.
This type of current is called ripple DC
What is the DC created by rectified AC?
This part of a 3 part regulator has a normally open relay (points).
What is reverse current protection?
This is how we restore a generators ability to bootstrap. What does this do?
Flash the field. Restore residual magnetism.
The electrolyte of this type of battery doesn't change chemical state between charged and uncharged states.
What are nicad batteries?
What is magnetic induction?
This is an advantage of brushless generators specifically pertaining to aircraft in flight.
Brushless generators cannot arc, and are safer in flight.
How are starter motors wound? Why?
Series. To give higher torque.
Why are the brushes on an alternator smaller than on a generator?
The rotating portion of an alternator is the magnet, which needs only a small amount of current to excite it (make it magnetic). Smaller brushes are needed than for a generator which needs large brushes to carry the full generator current to the load.
This uses 6 diodes to rectify current.
What is an alternator rectifier?
This part of a 3 part voltage regulator has a normally closed relay (also called points).
What is a current limiter.
This is a low resistance situation where current goes somewhere other than its intended destination.
What is a short?
This battery needs an acidic solution to neutralize its electrolyte.
What is a Nicad battery?
This problem can happen because of weak brush springs and can be corrected with capacitors connected to ground.
What is AC hash noise caused by brush arcing?
This is a variable hydraulic pump that provides fluid power to a motor or generator.
What is a constant speed drive?
These three factors determine the strength of voltage and current created in an magnetic/inductive generation system.
•The strength of the magnetic field.
•The number of conductors.
•The speed that the magnetic field is crossed.
This rule state that when a current carrying conductor is placed inside a magnetic field, a force acts on the conductor, in a direction perpendicular to both the directions of the current and the magnetic field.
What is the left-hand rule?
Because the commutator is part of a conductor. The conductor on an alternator is the stator. A commutator relies on rotation to rectify current.
This is a multi-segmented device that turns AC current into DC current on older-style generators?
What is a commutator?
This part of a 3 part regulator has a coil wired in series with the armature.
What is a current limiter?