2A672 Volume 2 Frequency Converter Components

76 Questions | By Chorne1787 | Updated: Mar 21, 2022 | Attempts: 243

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Volume URE for 2A672 Volume 2

Questions and Answers

1.

During operation of the EPU-6/E frequesncy converter it is determined that E and F pin voltage in not needed for the aircraft. The operator places the Loop/bypass/28 V to aircraft switch to what position?
- A.
  
  28 V to aircraft
- B.
  
  Neutral
- C.
  
  Bypass
- D.
  
  Loop
2.

Which of the following components provides 525 VAC to the control transformer of the EPU-6/E frequency converter?
- A.
  
  Input auto transformer
- B.
  
  Output auto transformer
- C.
  
  Input phase sequence transformer
- D.
  
  Output phase sequence transformer
3.

What EPU-6/E components receive potential directly from the input auto transformer?
- A.
  
  Analog board and alarm display
- B.
  
  Control transformer and voltage control
- C.
  
  Input circuit breakers and display power supply
- D.
  
  SCR voltage regulator and phase sequence transformer
4.

The control transformer perform on the EPU-6/E frequency converter provides
- A.
  
  28 VDC for the aircraft contactor
- B.
  
  240 VDC for the aircraft contactor
- C.
  
  120 VAC for the operation of E and F line 28 VDC power supply
- D.
  
  240 VAC for operation of E and F line 28 VDC power supply
5.

What EPU-6/E frequency converter components must be inspected prior to use?
- A.
  
  Air inlets for blockage
- B.
  
  Wiring for secure mounting
- C.
  
  Maintenance panels for corrosion
- D.
  
  Interior air vents for secure mounting
6.

During operation you determine that there is an undervoltage fault problem with the EPU-6/E frequency converter unit. What component could be malfunctioning?
- A.
  
  Analog board has failed
- B.
  
  Output trim potentiometer is centered
- C.
  
  Voltage control board potentiometer is shorted
- D.
  
  Audible alarm switch is in the silence position
7.

During operation of the EPU-6/E frequency converter you determine that one phase voltage is lower than the other two phases. What could cause this malfunction?
- A.
  
  Malfunctioning transister
- B.
  
  Burnt control transformer fuse
- C.
  
  Improper SCR firing adjustment
- D.
  
  Loose push-on connector on the output filter capacitor
8.

What -95 gas turbine compressor section supplies high-volume, low-pressure air for combustion, cooling, and bleed air output?
- A.
  
  Turbine section
- B.
  
  Accessory section
- C.
  
  Compressor section
- D.
  
  Air regulator section
9.

The function of the deswirl ring on the -95 gas turbine compressor is to
- A.
  
  Accelerate air
- B.
  
  Increase air pressure
- C.
  
  Decrease air velocity
- D.
  
  Smooth turbulent air flow
10.

What -95 component isolates the second-stage air from the operation of the first-stage compressor?
- A.
  
  Interstage ducts
- B.
  
  Interstage seal
- C.
  
  Impellers
- D.
  
  Inducers
11.

What prevents overpressurization of the bearing cavity on a -95?
- A.
  
  Oil jet
- B.
  
  Oil cooler
- C.
  
  Scavenge pump
- D.
  
  Oil tank vent line
12.

What -95 chambers are pressurized when the butterfly valve is closed?
- A.
  
  1 and 3
- B.
  
  2 and 4
- C.
  
  1, 2, and 3
- D.
  
  1, 3, and 4
13.

The -95's rate-metering valve prevents the butterfly valve from snapping open by bleeding air through the atmospheric bleed port from chamber
- A.
  
  1
- B.
  
  2
- C.
  
  3
- D.
  
  4
14.

What -95 component closes to complete the electrical circuit to the fuel solenoid and ignition unit?
- A.
  
  Load switch
- B.
  
  Oil pressure switch
- C.
  
  Turbine start switch
- D.
  
  35 percent centrifugal speed switch
15.

What preliminary set-up step, if skipped, prevents the -95 from starting?
- A.
  
  Set-up controls
- B.
  
  Set parking brakes
- C.
  
  Open and secure the exhaust door
- D.
  
  Ensure the turbine air inlet and exhaust doors are free of obstructions
16.

On the -95, discharge air pressure at 100 percent engine speed should indicate
- A.
  
  55 +2 psig
- B.
  
  45 +2 psig
- C.
  
  35 +2 psig
- D.
  
  25 +2 psig
17.

The -95 does not shut down when the charging rate decreases to 12 amperes. What is the probable cause of this trouble?
- A.
  
  Air load switch
- B.
  
  Fuel level relay K5
- C.
  
  2 speed solenoid SV4
- D.
  
  Battery charging module
18.

When heat is applied to an ice cube and the ice starts to melt, it is
- A.
  
  Super heat
- B.
  
  Latent heat
- C.
  
  Sensible heat
- D.
  
  Convection heat
19.

The three methods of heat transfer are
- A.
  
  Sensible, latent, and super heat
- B.
  
  Sensible, convection, and conduction
- C.
  
  Conduction, convection, and radiation
- D.
  
  Conduction, convection, and super heat
20.

The air flowing through an air conditioner is also called
- A.
  
  Heat
- B.
  
  Heat load
- C.
  
  Pounds per minute (ppm)
- D.
  
  Cubic feet per minute (cfm)
21.

While you are doing an ops check of an air conditioner, you notice the unit is short cycling. What do you do to correct this trouble?
- A.
  
  Increase the heat load
- B.
  
  Lower the refrigerant charge
- C.
  
  Check the receiver outlet valve
- D.
  
  Decrease the setting of the LPCO
22.

Bubbles in an air conditioner refrigeration system sight glass probably indicate
- A.
  
  Refrigerant overcharge
- B.
  
  A low refrigerant charge
- C.
  
  High discharge temperature
- D.
  
  Low discharge air temperature
23.

What MA-3D air conditioner component controls refrigerant flow into the evaporator?
- A.
  
  Quench valve
- B.
  
  TXV solenoid valve
- C.
  
  Hot gas bypass circuit
- D.
  
  Electric expansion valve
24.

The temperature controller on an MA-3D air conditioner opens the hot gas bypass valve if the
- A.
  
  Air pressure is too low so the boiling point of the R134a must be increased
- B.
  
  Suction air pressure is too high so the boiling point of the refrigerant can be decreased
- C.
  
  Suction pressure is too low so the boiling point of the refrigerant must be increased to increase the output air temperature
- D.
  
  Suction pressure is too high so the boiling point of the refrigerant must be decreased to decrease the output air temperature
25.

You place the MA-3D air conditioner SW1 in the START position, but the engine does not operate. What is the probable cause of this trouble?
- A.
  
  K7 contacts are closed
- B.
  
  Overspeed switch is closed
- C.
  
  Oil pressure switch is closed
- D.
  
  Override switch is not closed