Re: [doc] Coil Pulse Duty?

[Nick Tomlinson <nickandkathryntomlinson@xxxxxxxxxxx>]

I test distributors from scrap yards by mounting them in a vice and then using an electric drill on the shaft to spin it. If it's electronic then I use an oscilloscope on the hall effect pickup or on old contact breaker systems apply 12v to contact breaker and oscilloscope to the switched contact point.
   
  NickT

Nick Tomlinson <nickandkathryntomlinson@xxxxxxxxxxx> wrote:
    Hi,
   
  Who said my car was running? ok, it is.
   
  What do you exactly mean by pulse duty?
   
  The switching of the coil is dependant on engine rpm.
  For example (assuming even fire for simplicity)
  1000 rpm is 6000 'coil sparks' per second (6 cyl per enigne)
  Periodicity is 1/6000 seconds i.e. 0.16ms (milli seconds)
   
  5000 rpm is 30,000 'coil sparks' per second
  Peridiocity is 1/30,000 seconds i.e. 0.03ms
   
  if you are referring to the 'dwell' i.e. the open to close time ratio of the switching action, the ratio of voltage applied to the coil to in DC voltage (similar to the old contact points 'dwell) then according to my info this is electronically calculated.
   
  You could get a rough idea if it is switching if you put a dwell meter on the -1 side of the coil and see if it is triggered.
   
  If you have a non runner and want to confirm switching of ignition amplifier use a 'scope on the -1 of ignition coil. 
   
  Don't forget a dodgy or even short noise suppressor my effect this switching as it is parrallel in circuit to 0v (car earth -ve battery terminal)
   
  If you are refering to the coil pickup then the waveform would vary on engine speed and voltage would be from 0.3v at idle to 100v at full revs.
   
  dv = -dH/dt
   
  NB The trigger / stator pole gap should be 0.25mm
   
  Would a photo of an oscilloscope waveform of the switching action on the -ve coil terminal or across the distributor coil pickup answer your questions?
   
  NickT
   
  p.s. ok, you can all wake up now..........

Martin Gutkowski - DMC Ltd <martin@xxxxxxxxxxxxxx> wrote:
  
Hi All, especially those electronically inclined who have access to a 
running DeLorean and an oscilloscope.... (ruling our Rich H due to head 
gaskets, and Rich J due to his engine being in bits on our floor) So 
that'd be Nick then? :-)

Can you tell me or do you know the pulse duty on the coil trigger?

Best Wishes

Martin



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