Cabin AC Power Conversion System troubleshooting aid
Effectivity: Global Express, XRS, Global 5000, Global Vision aircraft
ATA: 24
By: Sebastien Desmitt—Technical Services Bombardier would like to provide a detailed description and guidance to pilots, flight attendants and maintenance crews to prevent unnecessary 115VAC, 60Hz frequency converter removals or troubleshoooting time. In some instances, it was noted that confusion may exist between the frequency converter, the Ground Fault Interrupter (GFI) and the two (2) Amp lcircuit breaker (CB) located at each single cabin seat. New SmartFixPlus troubleshooting observed faults are also available on the Customer Portal.
Aircrew and Flight Attendant - System description and limitation
To avoid nuisance tripping of the frequency converter, the GFI, or the local CB, each cabin or cockpit electrical power outlet load limitation must be respected as described in the Cabin Handbook or illustrated on each outlet placard (e.g. passenger seat = 2 A or 230W max). Most importantly, the total current draw of the system should never exceed the frequency converter capacity. Exceedance will shorten its lifespan or may damage the unit permanently.
Refer to the following table for cabin electrical outlet load limitations and suggested appliance use.
Warning: Continuous electrical overload exceeding 30A / 3450W may affect frequency converter reliability.
Bombardier does not recommend using more than one appliance in the galley at any time. For example, using an electric kettle and a hot plate at the same time could cause the frequency converter to operate above its limitations. For aircraft with two frequency converters, the load should be split between the two units. Consult your cabin electrical design to learn how to properly distribute the load.
Note: Be sure to use the vacuum cleaner and personal appliances with high power consumption in the outlets dedicated to that kind of usage (as listed in the above CABIN ELECTRICAL OUTLET LOAD AND USAGE table).
Once again, to reduce cabin electrical outlet power outages, Bombardier recommends following load limitations as stated in the aircraft-specific Cabin Handbook. The total capacity of the frequency converter should always be considered when using off-the-shelf appliances.
Aircrew and Flight Attendant -Troubleshooting tips
The following tips assist with troubleshooting the cabin electrical power outlet system.
If only specific outlets are affected:
Verify where electrical power is not available: an entire zone (e.g. all the outlets on the R/H cabin, galley, cockpit, etc.) or only at one seat location.
If electrical power is not available in an entire zone, the affected GFI may be tripped. Refer to the Cabin Handbook for GFI locations. GFI must be powered when a reset is performed.
If electrical power is not available at only one cabin seat location, a reset or an integrity verification of the local breaker 2A may be performed.
Note 1: To activate and reset galley GFIs in the affected aircraft, the tambour doors must be fully open. In some cases, serviceable GFIs were removed due to a tambour door switch adjustment problem.
2. If 115Vac power is not available at all cockpit and cabin outlets:
Note: If an aircraft is equipped with dual frequency converters and one converter is tripped or defective, the electrical power won’t be available in the covering zone of that frequency converter.
Verify on Galley Touchscreen Equipment (GTSE) if the frequency converter fault message is displayed.
VENUE CMS Screenshot
CES-5000 Screenshot
Confirm that the aircraft is not in oxygen mode (EICAS advisory message “PASSENGER OXY ON”, all cabin reading/table lights activated, audio and video entertainment stopped, etc.).
The frequency converter is disabled when the oxygen system is ON.
Verify the ON/OFF RESET switch position on the front panel of the frequency converter in the avionics bay (requires maintenance action) —make sure it is in operational position.
Maintenance Personnel –Troubleshooting tips
System Description
The power source of the system consists of a frequency converter (some aircraft are equipped with optional dual frequency converters) located in the avionics bay. This converts the 3-phases 115VAC, 400 Hz of the Alternative Current Power Centre (ACPC) to a single phase 115VAC, 60Hz. The system supplies power to universal outlets through the Cockpit Circuit Breaker Panel (CCBP) and many Ground Fault Interrupters (GFI) throughout. The GFI protects people against electrical current leakage and will trip before a harmful electrical shock occurs. The GFI contains a TEST and a RESET button to verify the protection circuitry. In accordance with Supplemental Time Limits/Maintenance Checks (STLMC), GFIs and cabin outlets must be periodically tested every 15 months.
Refer to Supplemental Maintenance Manual (SMM) Chapter 24 and the Cabin Handbook for aircraft-specific cabin configuration.
CABIN POWER ELECTRICAL FLOW
Generic simplified schematic for VENUE cabin system
New troubleshooting tasks for isolating and diagnosing cabin outlets or frequency converter failures are now available on the SmartFixPlus troubleshooting tool, web-based format, available on the Bombardier Customer Portal.
2. With the current CB arrangement, it is possible to overload the frequency converter beyond its maximal 30 Amp rating for an extended period, which may compromise reliability. The addition of a thermal 25 Amp CB on the CCBP helps keep the total power within the limits recommended by the supplier. This minor modification is now available through these recommended service bulletins:
700-24-6013
700-24-5013
700-1A11-24-027 release Dec/2018
700-24-088 release Dec/2018
Part of the SB kit is a plastic-covered briefing card. Using simplified pictograms, it provides aircrew with examples for managing the total cabin electrical power throughout all aircraft zones (cockpit, galley, lavatories etc.).
