tegwin
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posted on 28/8/13 at 04:54 PM |
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Haha.. Yes I had thought about using a blow-torch to light the thing...
But my designs are a little more suffisticated. I intend to have a fully automated digital electronic control (FADEC) unit for a 1 button start and
run..... So I need everything to work properly from the off
The start sequence will involve an electric blower puffing through the combustor to provide air for the ignition and to spool the turbine up. I think
you are right that two or three good quality sparks a second would be more than sufficient.
I don't like the idea of using the transistor as it gets hot and is obviously not the ideal design...I think I need to try something a bit more
inteligent.
Do we think the ignition amp from maplins (link above) would do the job if driven with a small transistor from the 555?
I will post some pics in a week or so once I get things bolted back together. Just at the stage of testing the ignition and fuel systems. once that is
done I can plumb up the lubrication and monitoring systems and see if she will run
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MikeRJ
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posted on 11/9/13 at 03:35 PM |
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quote: Originally posted by BaileyPerformance
It's the diode across the 2055 that's clamping the fly back and preventing the coil from releasing the charge to the secondary.
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If you look at the circuit carefully, this diode is not doing any clamping from flyback voltages. When the 2N3055 switches off, and the current in
the coil primary starts to collapse, the voltage at the collector will rapidly increase. This means the 1N4007 is being increasingly reverse
biased rather than forwards biased, so is not conducting.
A suitable value of zener diode in this position could be used to clamp the C-E voltage, but the power dissipation if limiting the voltage under 60v
would be pretty high.
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