Javier,
Assuming that you have a 912 the size of the air gap of the trigger coil
is critical. If you look at the Rotax installation manual for the 912 on
page 51 you will see the graphs of the voltage output from the trigger coil.
Although there is only one major peak in 360 degrees there are some minor
ones. I suspect that at high rpm, when the voltages produced are relatively
high, the secondary peaks can become significant if the gap is incorrectly
set, giving two or more impulses per revolution. I had the problem that you
describe but it disappeared when Rotax Service Bulletin SB-912 026/E was
incorporated (replacement of the stator assembly) part of which was to reset
the coil gaps. The gap for an old type trigger coil should be 0.016" to
0.020" and for the trigger coil with clamps should be 0.012" to 0.016"
Hope this helps,
Roger. (G-BXTD)
----- Original Message -----
From: "Barahona Alonso, Francisco Javier" <javier.barahona@aeasa.com>
Subject: rpm gauge malfunction
> I have a repetitive problem with my rpm gauge. First time, after about 35
> hours of working, at full power the indication started to oscillate
reaching
> even the maximum range. I decided to change de gauge and the problem
> disappeared. After about 15 hours of flying the problem has been repeated
> with the new gauge.
>
> Has somebody any idea about what the problem is?
>
> Thank you very much
>
> Javier Barahona
> Spain
> (Classic 187)
>
|