AMS 366 - Unit 3
How are Gen rated?
1. Amps 2. KVA 3. Phase # 4. Speed Rating 5. Power Factor 6. Freq 7. Volts
What is a Split Bus?
No operation of 2 or more generators operating the same AC bus(es)
A CSD unit drives a generator through the use of
a variable hydraulic pump & hydraulic motor
What is the input to the load controller?
signal from the CT Loop
What is the flight deck control and indication for Ext Pwr?
"Power Available" Light and a Selector Switch
What is Reactive Power?
"Reflected" by the loads "Back" to the generator; Volt is NOT in phase w/ the current; Power is NOT consumed by the Loads
How many Load Controllers are there?
1 per gen
How many GCUs are there?
1 per generator
How do you Service CSD fluid?
1. Check Level w/in 1 hour of shutdown 2. Sight Glass checked for level 3. Some may require to service to determined correct level 4. Location on A/C may determine level
What does the BPCU do?
1. Controls per distribution through the "Tie (Sync)" Bus 2. Manages Ext Pwr 3. Provides protection for the Tie/Sync bus & Ext pwr 4. May contain APU Controls
How does the VR Control Gen Output Volt?
1. Controls the executor field 2. Controls the GCB 3. Controls the BTB
How is the APU monitored?
1. Gen Freq 2. Gen Volts 3. Engine Annunciator Lights 4. Engine EGT 5. Gen Ammeter
What does a GCU contain?
1. Volt Reg 2. Field RLY 3. Output RLY control 4. "Bus Tie" RLY Control 5. Protection
How are Gens monitored?
1. Volts (Phase to Neutral) 2. Freq 3. Amps (Ammeter, Apparent Pwr, Real Pwr, Reactive Pwr)
What can the Wye Stator output?
120 VAC Single phase 208 VAC Single Phase 208 VAC Three Phase
Paralleling of AC generator require how many paralleling circuits?
2
How many cycles of ac voltage are produced in a six-pole alternator of the revolving-field type for each revolution of the rotor?
3
What is the Chip Detector?
A Magnet; Samples the mag. particles in the fluid stream for inspection (Not A Filter)
Aircraft which operate only ac generators (alternators) as a primary source of electrical power normally provide current suitable for battery charging through the use of
A step down transformer and a rectifier
When necessary during operation, CSD disconnect is usually accomplished by
A switch in the cockpit
What is the DC Receptacle on the External power plug used for?
APU Starting
When is CSD Disconnect performed?
Above Idle
How are Gens cooled?
Air Cooling or Oil Cooling
A battery-generator system provides direct current. On installations requiring alternating current from the battery-generator system, it is necessary to have
An Inverter
What is the purpose for the Aux Bearings?
Back-Up for Main bearing Failure
How is Main Bearing fail sensed?
Bearing Temp and Outer race end frame contact
What does BPCU stand for?
Bus Power Control Unit
The major advantages of alternating current (AC) over direct current (DC) is the fact that its current and voltage can easily be increased or decreased
By means of a transformer
How is CSD monitoring accomplished?
Chip Detector, Fluid Temp, Annunciator Light, Filter and Fluid Inspection
What is the purpose of the BTB?
Connects gen to other gen busses
What does a GCU do?
Contains several functions to mange a particular generator
What is the Voltage Regulator?
Control gen output volt
What does the Output Generator do?
Converts DC to AC
What is a Constant Speed Drive?
Converts the variable engine speed to a constant speed output to drive the gen @ a fixed rpm
What are usually out of phase?
Current and Volt
The inductor-type inverter output voltage is controlled by the
DC stator field current
How is fluid cooling accomplished?
Dedicated Oil Cooler (Heat Exchanger Oil/Air)
What type of Stator is not used?
Delta
What does the Exciter Generator do?
Driven by the Engine and produces AC
What is the Load Controller?
Electronic sensing and control device for real load division
What type of Annunciator lights are there?
Excessive Fluid temp or Low fluid Press or BOTH
Where is the Permanent Magnet located?
Exciter Gen
What is the Filter Indicator?
Filter Bypass/Clogged (Excessive debris on the filter)
What is the Breech mounting?
Flange turns and tightens gen to CSD or CSD to engine
What is required when operating two aircraft ac generators in parallel?
Frequency and Voltage must both be equal
What are some examples of DC Essential Loads?
Gen Controls IDG Disconnect Flight station lights Air/Fuel sys isolation valves Landing Gear controls Cam/Nav Sys Caution/Warning Indication
What is a GCU?
Generator Control Unit
One advantage of using ac electrical power in aircraft is
Greater ease in stepping up or down
What is ground on the Wye?
Ground
What is the purpose of External Power?
Ground Ops
What are the advantages of AC?
Higher Pwr to Wgt Higher operating Volt allows smaller gauge wire Simple to change volt values Easily rectified to DC
What is IDG?
Integrated Drive Generator; Combines the CSD and Generator
What are the CBs in the system?
Latching RLYs
What is the purpose of a CT?
Looking @ current signals
What is the Buss Distribution?
Main Bus feeds many smaller busses
What is a Standby/Essential loads/busses?
Main Bus; Loads that are critical to maintain the flight integrity of the A/C ("Loads that get you home")
What is a Parallel Bus?
May operate 2 or more generators on the same AC bus(es)
How is the disconnect accomplished in the CSD?
Mechanically OFF to Gen and CSD
How is the stud mount accomplished?
Nut started on the CSD/Gen then rotate the whole thing then torque
CSD driven generators are usually cooled by
Oil Spray
What are the two types of Fluid temp taken from the CSD?
Oil Temp In/Out and Oil Temp Rise
A CSD unit that is disconnected in flight, due to a malfunction such as overtemperature, may be reconnected
Only on the ground by maintenance personnel
How is reactive load division accomplished?
Parallels reactive power; Voltage Regulation
How is Real Load Division Accomplished?
Parallels real power; Controlled by generator drive torque
How is Self-Excitation accomplished?
Permanent Magnets and PMG
What is Real Power?
Power "Consumed" by the loads; When Current/Volt are in phase
What is Apparent power?
Power produced by the gen w/ no regard to volt/current lead/lag
What is the PMG Rotor used for?
Powersupply for components
What is CSD Disconnect?
Provide a means to uncouple the gen & its drive during engine op
What is the frequency of an alternator dependent upon?
RPM
What paralleling circuit is the VR a part of?
Reactive Load Division
What parallel circuit does the Load Controller control?
Real Load Division
What are the two paralleling circuits called?
Real Load Division and Reactive Load Division
In an ac circuit with no phase lead or lag, which is true?
Real power equals apparent power
Certain transport aircraft use ac electrical power for all normal operation and battery furnished dc electrical power for standby emergency use. In aircraft of this type that operate no dc generators, the batteries are kept charged by
Rectifiers which use the A/Cs AC Gen as a power source
What are some AC examples of Essential Loads?
Select Engine Instruments A/C Electronics Com Sys Flight Data recorder Nav Sys
What is the PMG Stator used for?
Self-Excitation
What is the output of the Load Controller?
Signal drives the CSD RPM speed governor
What are the two basic bus Configurations?
Split and Parallel
How are CSD Installed?
Stud Mount and Breech Mount
What system are Load Controllers on?
Sync
What is Oil Temp Rise?
Temp Increase of the fluid as it flows through the CSD (Temp Out minus Temp in)
What is oil Temp In/Out?
Temp of fluid enter or depart the hydro-mechanical activities
How is the gen freq controlled on the APU?
The APU runs at the On Speed required
How is External power plugged in?
Through 1 (Maybe 2) AC Receptacles on the front lower fuselage
What are the external power types?
Trailer and Jetway Power pack
What is CSD fluid?
Turbine Engine Oil
What is the APU?
Turbine engine driving a gen and air compressor
What is a Current Transformer?
Used to determine current through a conductor
What is the Fluid Inspection?
Visual Inspection; Should be the color of light beer
What is the Unit for Reactive Power?
Volt-Amp (VAR)
What is the Units for Apparent Power?
Volt-Amps (VA)
The voltage output of an alternator may be regulated by controlling the
Voltage output of the dc exciter
When paralleling AC Gens, what must be the same between the multiple Gens?
Voltages, Freq and Phases
What is the unit for Real Power?
Watt
What is on speed?
When RPM is enough to maintain 400 Hz
What is the load priority of the APU?
Which ever sys needs more
What type of Stator is commonly used?
Wye
Integrated drive generators (IDG) employ a type of high output ac generator that utilizes
a brushless system to produce current
If the Integrated Drive Generator (IDG) scavenge oil filter is contaminated with metal, you should
remove and replace the IDG
