Section 3B

AC Power supplies

03/03/04 AC power coupling installed, port trailing edge wing.

03/2004. Currently all ac power supplies are disabled, and fuses removed to prevent inadvertent operation of the main AC bars, until all supplies can be tested.

The 115V three phase standby inverter supplies have been isolated and fully tested and are safe. However there is currently a problem with the type 100A-inverter overheating, due to an unknown load or phase problem. This will be investigated and rectified in due course.

01/5/2004

After a thorough investigation into the power drain on the type 100A-inverter, no drain has been found. Final conclusion lead to removing the inverter and type 12 controller to investigate overheating further.

The inverter was sent to ‘J Booker’ for inspection and overhaul where required. Upon disassembly, it was found that the main bearings and commutator were badly worn and water damaged. The inverter was stripped fully overhauled, then bench tested for 18 hours straight, no further faults are found. Type 12 controller required no overhaul. Type 12 surpressor was tested also, and found to be faulty. One 450V 0.05 Mf capacitor had broken down, causing a short and the resultant outage of one AC phase, hence the overheating problem with the inverter. All capacitors have been replaced. Inverter and controller are due for refit, completing restoration of the standby inverter circuits.

The normal XA, XG and XF AC bars will be tackled next.

Above type 12 stand by inverter controller and filter, removed from airframe