kontiki99
Electrical
- Feb 16, 2006
- 510
I work in an airline Engineering Support Group that supports the aircraft maintenance division. One of our chronic problems involves troubleshooting the electrical system on older 3 engine aircraft. When an aircraft has an odd number of engine driven generators or just a lot of them (as in 747), generators are paralleled on a bus to share the load. Our older aircraft have limited fault reporting ability. I've read that aircraft fault reporting systems probably at best are capable of showing us 20% of the possible faults. The original designers are long gone from the industry. The maintenance support documentation is limited.
I'm looking around for a couple things:
Any body know of a tester that would be suitable for real time comparison of two 3 phase 400hz 115VAC generators that could display metrics that would tell us if the output of one of the generators is in fact marginal for paralleling.
Anyone know of any written material I could look at to get up to speed on different technical/design aspects of paralleling generators in general.
I remember decades ago as a turning a knob on the engineers panel of a 727-100 until two flashing light bulbs synchronized before toggling the bus tie switch. In the aircraft we support now (a newer tetradactyl), the generator control units and look for freq, current, voltage faults, and report to an electrical power control unit. Our airplanes do have a fairly detailed electrical synoptic display probably designed for the pilots, but it doesn't show us why when a GCU refuses to tie.
Typically the control unit issues cryptic codes and the parts cannon fires hoping to replace the faulty sensor, relay or generator in the hopes of making the message go away. It's not unusual for it to take several maintenance visits to resolve the issue. I can't help but to think there must be a better way.
My posts reflect my personal views and are not in any way endorsed or approved by any organization I'm professionally affiliated with.
I'm looking around for a couple things:
Any body know of a tester that would be suitable for real time comparison of two 3 phase 400hz 115VAC generators that could display metrics that would tell us if the output of one of the generators is in fact marginal for paralleling.
Anyone know of any written material I could look at to get up to speed on different technical/design aspects of paralleling generators in general.
I remember decades ago as a turning a knob on the engineers panel of a 727-100 until two flashing light bulbs synchronized before toggling the bus tie switch. In the aircraft we support now (a newer tetradactyl), the generator control units and look for freq, current, voltage faults, and report to an electrical power control unit. Our airplanes do have a fairly detailed electrical synoptic display probably designed for the pilots, but it doesn't show us why when a GCU refuses to tie.
Typically the control unit issues cryptic codes and the parts cannon fires hoping to replace the faulty sensor, relay or generator in the hopes of making the message go away. It's not unusual for it to take several maintenance visits to resolve the issue. I can't help but to think there must be a better way.
My posts reflect my personal views and are not in any way endorsed or approved by any organization I'm professionally affiliated with.