AMS 366, A/C Instruments - Unit 3

What is ground on the Wye?

Neutral is airframe grounded

Integrated drive generators (IDG) employ a type of high output ac generator that utilizes

a brushless system to produce current

A CSD unit drives a generator through the use of

a variable hydraulic pump & hydraulic motor

If the Integrated Drive Generator (IDG) scavenge oil filter is contaminated with metal, you should

remove and replace the IDG

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

2 generator cooling methods

- Air Cooling - Oil Cooling

How is Main Bearing fail sensed?

- Bearing Temp - Outer race end frame contact

2 types of stators

- Delta - Wye

What are the advantages of AC over DC?

- Higher Power/weight ratio - Allow smaller gauge wire - Simple to change volt values (transformers) - Easily rectified to DC

What are the two basic bus Configurations?

- Split - Parallel (Sync)

When paralleling AC Gens, what must be the same between the multiple Gens?

- Voltages - Freq. - Phases

How many Gens does it take to power essential loads?

1

How many Load Controllers are there?

1 per gen

How many GCUs are there?

1 per generator

How are Gen rated?

1. Amps 2. KVA (Power) 3. Phase # 4. Speed Rating 5. Power Factor (PF) 6. Frequency (Range) 7. Volts

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

What is the Chip Detector?

A Magnet; Samples the mag. particles in the fluid stream for inspection (Not A Filter)

Exciter Generator

A coil that provides stationary rotating magnetic field, which is used to induce the EMF in the armature coil, strengthening the magnetic field of the alternator

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

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 Auxiliary Bearings?

Back-Up for Main bearing Failure

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

AC Output Generator

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 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

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 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 the purpose of External Power?

Ground Ops

What is IDG?

Integrated Drive Generator; Combines the CSD and Generator

What are the CBs in the system?

Latching RLYs

How does Real Load Division work?

Load controller respond by signaling the CSD to adjust gen driving torque

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")

Parallel Bus System

May operate 2 or more generators on the same bus

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

PMG

Permanent Magnet Generator

What allows self excitation?

Permanent Magnet Generator; Residual voltage is produced during rotation

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?

Power supply 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 output of the Load Controller?

Signal drives the CSD RPM speed governor

Generator Oil Cooling

Spraying oil through the generator

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

Split Bus System

Two separate electrical systems

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

How does the Reactive Load Division work?

Volt Reg respond by adjusting executor current to balance the reactive component of the Apparent Power

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

What is the unit for Real Power?

Watt

What is the load priority of the APU?

Which ever sys needs more

What type of Stator is most commonly used?

Wye