On 25/07/2015 14:26, Greg Fuchs wrote:
> Richard-or anrman, you tried 4 new Regulators, WOW! Why did they not work
> for you, and was it related to the 5 Cycle/second current pulses? (I will
> need to get a new one at some point). Interesting point about the analog
> gauge..
> Regards,
> Greg
I know I was amazed ! My first (Ducati) R/R died at 175
hours. I bought one from the Rotax importers in the UK.
When connected up to exactly the same wiring as the
original one the (analogue) ammeter needle vibrated
between 2 and 10 amps 5 times per second. This meant that
the voltage was moving between 14v and someting else (16v
?) on the same frequency, but the voltmeter needle is
damped and so it didn't show up.
I sent it back and got another. Same result. Bought one
---From Lockwood in the US, same result, and sent it back,
and the replacement did the same.
OK at this point I really thought it was me or the plane.
Then borrowed an older R/R from someone else. No
vibration. Unfortunately it was only a loan ! What i
decided was that at some point they changed the circuit
and after that date the voltages were controlled
differently. I did have an approx date for that cut off
(the manufacture date is stamped on the casing) but i
don't have it to hand. Sometime around 2005 I think.
As I say it may just be me, but my analogue needles showed
me something that digital wouldn't have shown; and nor
would a voltmeter (or an ammeter) alone.
So I bought a Schicke. Slightly lower max current but a
whacking great heat sink. That has done 600 hours now with
no problem or vibration whatsoever (I expect because I
have a spare which I carry in the aircraft !)
Apparently there is a Deere Tractor R/R which is built
like a br*ck-sh*thouse which also works and has spare
capacity for ever and ever. I found that on Google somewhere.
Sorry about the rant. I was worse at the time; you have
re-awakened my thinking on this !
HTH
Richard
> i am going to offer my 10 cents worth
>
> These problems are why you need to have an ammeter AND a voltmeter to give
> sufficient information. Ammeters can either show current in and out of the
> battery (with a -30 0 +30 type scale), or measure the current out of the
> alternator (0 +30 scale). In and out of the battery is more useful.
>
> And i go further and say that digital meters only sample maybe 5 times a
> second. You need analogue meters with pointers. Without my analogue ammeter
> I would not have known that my charging system was fluctuating from 2 to 10
> amps on a 5 cycles per second basis.
>
> I tried 4 new rectifier/regulators and they were all the same. Apparently
> they had changed the design ! I put a Schicke regulator on and all was well.
> I did try a used but older R/R and it was fine as had been my original.
>
> Electrics are really simple but you have to go back to first principles and
> understand what is actually happening.
>
> The stator on the flywheel is very reliable. The wiring and R/R are not. I
> would do comprehensive checks on the wiring and the R/R (and maybe the rest
> of your electrics) befor eeven considering fiddling with the stator.
>
> Is the body of your R/R earthed ?
>
> Richard Holder
> aka anrman :-)
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