REQ: Tiny Tach wiring assistance

We have a 'Robins 440 motor' that was running a tiny tach, everything ran
fine untill the motor was taken out for overhaul... (hmmmm) whomever was on
that side of the aircraft when we lifted the donk out failed to disconnect
the red tiny tach lead and now we dont know what it connects up to...

Tried every thing, the best we can get gives us 1800 idle then quickly goes
to 7100 on small throttle movement..

anyone got a hook up diagram for one of these.

Trevor.
Australia

The red lead simply makes a few wraps around the spark plug wire.

Q

"PureEmotion" <Trevor@PureEmotion.com.au> wrote in message
news:402b47db$0$4255$afc38c87@news.optusnet.com.au ...
> We have a 'Robins 440 motor' that was running a tiny tach, everything ran
> fine untill the motor was taken out for overhaul... (hmmmm) whomever was
on
> that side of the aircraft when we lifted the donk out failed to disconnect
> the red tiny tach lead and now we dont know what it connects up to...
>
> Tried every thing, the best we can get gives us 1800 idle then quickly
goes
> to 7100 on small throttle movement..
>
> anyone got a hook up diagram for one of these.
>
> Trevor.
> Australia
>
>

> The red lead simply makes a few wraps around the spark plug wire.

5 wraps to be specific with each turn touching the other, side-by-side
(ie a small tighly wound coil). Less than five may result in erroneous
readings. Greater than five, like four or five turns more, will too.

Obviously, the coil becomes an inductive pickup, transforming the
expanding and collapsing magnetic field generated by the spark pulses
into electrical voltage in the coil/wire sensed/counted by the tach.

Thanks guys, so easy, no wonder there was no sign of broken connection.....

Trevor C
Australia


"Dean Scott" <dascott@southern.edu> wrote in message
news:c0g3us$165jid$1@ID-55556.news.uni-berlin.de...
>
> > The red lead simply makes a few wraps around the spark plug wire.
>
> 5 wraps to be specific with each turn touching the other, side-by-side
> (ie a small tighly wound coil). Less than five may result in erroneous
> readings. Greater than five, like four or five turns more, will too.
>
> Obviously, the coil becomes an inductive pickup, transforming the
> expanding and collapsing magnetic field generated by the spark pulses
> into electrical voltage in the coil/wire sensed/counted by the tach.
>

Whoooopppiiiii it works...
Thanks guys


"PureEmotion" <Trevor@PureEmotion.com.au> wrote in message
news:402b95e1$0$5224$afc38c87@news.optusnet.com.au ...
> Thanks guys, so easy, no wonder there was no sign of broken
connection.....
>
> Trevor C
> Australia
>
>
> "Dean Scott" <dascott@southern.edu> wrote in message
> news:c0g3us$165jid$1@ID-55556.news.uni-berlin.de...
> >
> > > The red lead simply makes a few wraps around the spark plug wire.
> >
> > 5 wraps to be specific with each turn touching the other, side-by-side
> > (ie a small tighly wound coil). Less than five may result in erroneous
> > readings. Greater than five, like four or five turns more, will too.
> >
> > Obviously, the coil becomes an inductive pickup, transforming the
> > expanding and collapsing magnetic field generated by the spark pulses
> > into electrical voltage in the coil/wire sensed/counted by the tach.
> >
>
>