Tacho earthing - - - coil question?

[libellav15]

Hi guys

I'm trying to get my head round why the wire between the coil '-'ve and the tachograph earthing out cause a no spark situation please?

cheers

adam

 

[Bt Doctur]

Re: Tacho earthing - - - coil question?

Bad tach, disconnect it from the tach and hook the wire back up to the coil.
runs=bad tach, dosent run=bad wire to tach.

 

[libellav15]

Re: Tacho earthing - - - coil question?

Cheers Doc

I get that bit buddy - but i am trying to get my head around why if that wire touches earth the spark stops

and indeed why when the shift interlock switch goes open circuit the spark stops - or does the switch go closed circuit when operating?

that would make more sense - ie be the same as the tacho wire earthing - but why does earthing the '-'ve side of the coil stop the spark?

i know i am thinking too much - i just love to understand things i am working on - makes it easier to remedy, remember, adjust etc

cheers again bud

adam

 

[Bt Doctur]

Re: Tacho earthing - - - coil question?

The neg side is what produces the spark, mechanical or electronic.
stop that from happening(ground) ,you have no spark.

 

[libellav15]

Re: Tacho earthing - - - coil question?

wonderful Doc cheers

above and beyond as usual

so in other words the system earths before it even gets to the points so no magnetic field is created

ok.. got it -- i know its probably obvious but if the primary winding normally creates a field by earthing through the closed points (earth) then why doesn't the primary winding charge when its earthed through a bad/'earthed tacho wire or interlock switch

or maybe it does - but surely it would just get hotter and hotter?

 

[bruceb58]

Re: Tacho earthing - - - coil question?

The primary windings certainly does have a magnetic field created when the negative side of the coils is grounded..that's how you create the circuit. Its the ungrounding of the coil which causes the field to collapse which then causes the spark out the secondary.

 

[libellav15]

Re: Tacho earthing - - - coil question?

Thankyou SOOO much guys.

Its midnight here and i have work in 3 hours - i can get some sleep now

Cannot sleep when I am trying to get something straight in the old noggin!!

Cheers again

Adam

 

[Blk-n-Blu]

Re: Tacho earthing - - - coil question?

PIP-PiP Cheerio mate