Beechcraft B350 GPU starting problems
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Beechcraft B350 GPU starting problems
Anyone had experience with Beechcraft 350's drawing a lot (2000 amps) at start and tripping the GPU ? What GPU's (28vdc) can handle this or is it back to the battery cart?
Join Date: Jan 2006
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help
Hi
kingairs do draw large amps at start up, causing spikes but should reduce quickly and some times the GPU cant deliver sufficient power. What I would try starting only the right engine with GPU, check current draw. Start only left engine and check current draw. if both generators draw same current I think the chances are the GPU is your problem.
If not
You notice a larger current draw from one of the generators you have a short in either the main wires on terminal B and C. You can check this with a multimeter by disconnecting the leads off the generators(the thick leads, mark them with tape when removing or you will blow a GCU if connected wrong). check for grounds, ensure master batt is off, this condition normally will show excessive charging on cabin amp meters and usually you have the problem of constantly replacing generators. Inspect wiring for signs of burning and chaffing. you can trace up to the contactor,
If not
or one of the windings(generator or terminal block), In the terminal block there are capacitors for suppression, if these short they can give you a ground, you must use a cap tester to check the caps, a tell tale sign will normally be static on headset when that gen is selected to on position.
If not
short in the generator winding,shorts down to ground due to carbon, this can be repaired, removing the gen and bench testing it will quickly indicate the status of the gen, A simple 220 volts test light will normal show up the track of carbon by giving a spark. I suggest you do not attempt this if you not licenced as generators are class 1 items and you have the experience, you are also working with 220 Volts so be carefull. You will require manuals and a Licenced signature for the repair of the generator.
Hope this helps, if the problem still persists and you find no solution to the problem I suggest you contact Raethem their technical staff are very sharp and will gladly assist you.
regards
kingairs do draw large amps at start up, causing spikes but should reduce quickly and some times the GPU cant deliver sufficient power. What I would try starting only the right engine with GPU, check current draw. Start only left engine and check current draw. if both generators draw same current I think the chances are the GPU is your problem.
If not
You notice a larger current draw from one of the generators you have a short in either the main wires on terminal B and C. You can check this with a multimeter by disconnecting the leads off the generators(the thick leads, mark them with tape when removing or you will blow a GCU if connected wrong). check for grounds, ensure master batt is off, this condition normally will show excessive charging on cabin amp meters and usually you have the problem of constantly replacing generators. Inspect wiring for signs of burning and chaffing. you can trace up to the contactor,
If not
or one of the windings(generator or terminal block), In the terminal block there are capacitors for suppression, if these short they can give you a ground, you must use a cap tester to check the caps, a tell tale sign will normally be static on headset when that gen is selected to on position.
If not
short in the generator winding,shorts down to ground due to carbon, this can be repaired, removing the gen and bench testing it will quickly indicate the status of the gen, A simple 220 volts test light will normal show up the track of carbon by giving a spark. I suggest you do not attempt this if you not licenced as generators are class 1 items and you have the experience, you are also working with 220 Volts so be carefull. You will require manuals and a Licenced signature for the repair of the generator.
Hope this helps, if the problem still persists and you find no solution to the problem I suggest you contact Raethem their technical staff are very sharp and will gladly assist you.
regards
