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Leburg tacho signal

Posted: Sun Jan 24, 2021 7:24 pm
by JimCrawford
I need to discover the format of the Leburg unit tacho signal - in particular the pulse width and if it is constant width or variable with speed. Voltage and positive going or negative going would also be useful.

Thanks in advance for any information.

Jim

Re: Leburg tacho signal

Posted: Mon Jan 25, 2021 9:49 pm
by Neil Spooner
Gosh,
What are you trying to achieve?
Neil

Re: Leburg tacho signal

Posted: Mon Jan 25, 2021 9:51 pm
by Neil Spooner
.......I doubt Skycraft would have a clue either....best get out the Oscilloscope and see for yourself?

Re: Leburg tacho signal

Posted: Tue Jan 26, 2021 6:35 pm
by JimCrawford
Nothing too exotic Neil !

I've removed the mechanical tacho link from my VW and want to use the Leburg output. Some time ago I speculatively bought some lovely surplus meters, 270 degree needle sweep and in a case which is geometrically compatible with the standard 80mm instrument format. Even marked 0 to 4 on the face so all I need add is a red line at 3300. I'll get a friend with a 3D printer to print an overlay so that it looks exactly like a purpose made aircraft instrument and so match the flight instruments very nicely.
I need to know the Leburg characteristics so that I can design an interface between the pulse signal and the analogue meter.

Jim

ps I've just spent a day in the garage roughing out some new engine mounts which move the engine 3mm forwards to clear the Leburg style alternator. Seems to have generated an amazing amount of swarf!

Re: Leburg tacho signal

Posted: Tue Jan 26, 2021 6:38 pm
by Neil Spooner
My guess would be a square wave at about 5v.

If you move your engine forward you are going to change the CofG..........

Re: Leburg tacho signal

Posted: Tue Jan 26, 2021 9:22 pm
by JimCrawford
Ah but if I move the batteries aft I can tune the CofG to exactly where I want it :D

Also it will give some clearance between the back of the prop and the front of the cowling. They were perilously close :shock: I think the engine mounts weren't Nipper original.

Jim