Alternators. Test #2
What type of rectifier is required on the alternator?
3 phase full wave.
How many fingers are on each segment?
7.
How is the rotor powered?
A coil of wires wound around an iron spool between two heavy iron segments that have interlacing fingers.
What three problems will cause low voltage?
Badly pitted points, Rotor coil shorts, and damaged diodes.
What two ways can an alternator be driven?
Belt drive, and accessory drive.
A alternator rotates in what direction?
Bi-Rotational.
What transfers the DC through the rotor to the slip rings?
Brushes.
what type of advantage does a delta stator have?
Current.
What excites AC current flow in the stator?
DC current in the rotor.
What type of electricity is created by a alternator?
DC current.
What type of electricity is in the rotor?
DC current.
What relay points are in series with the rotor and are spring loaded?
Field relay.
What are the advantages of alternators over generators?
High output at low RPM, good power to weight ratio, and no commutator.
What would happen to the output voltage if the upper points developed an open?
High voltage at high RPM.
What would be the result if the VR shunt was open?
High voltage.
What would be the result if the lower VR points were stuck closed?
High voltage.
What would be the result is the VR points were pitted?
High voltage.
What would the voltage be if the split rings were glazed?
Low voltage.
Where are the positive diodes located?
Mounted on the heat sink.
Where are the negative diodes located?
Mounted on the slip ring frame.
What are are the two types of bearings in an alternator?
Needle bearing (Roller), and ball bearing.
What would cause zero voltage?
Open to field, and VR are not grounded.
What is a disadvantage of a alternator?
Requires battery power.
How can the diodes be damaged?
Reversing polarity to the battery.
Where are the bearings located?
Split end and drive end frame.
What part of the alternator is induced?
Stator.
If polarity is reversed to the alternator what might be damaged?
The rectifier assembly or the diodes.
How is the output voltage of a DC alternator controlled?
Through the vibrating points (VR).
What is the purpose of the diodes in a alternator?
To prevent reverse current through the stator.
What is the purpose of a DC alternator?
To provide DC power to the DC bus of the aircraft.
A capacitor is used for?
To smooth out alternator output voltage.
What is the purpose of the brushes in an alternator?
Used to transfer DC field to the rotor through slip rings.
What prevents the battery from over charging?
Voltage regulator.
What type of advantage does wye Stator produce?
Voltage.
What are the brushes made of?
Carbon.