6VAC Breaker-Point Ignition Coil: Primary & Secondary Resist

This forum is a continuation of the printed column "Q&A", where I answer questions about all aspects of electronics, including computer hardware, software, circuits, electronic theory, troubleshooting, and anything else of interest to the hobbyist. Feel free to participate with your questions, comments or suggestions on answers printed in the magazine. Send all NEW questions to: [email protected]
Post Reply
EddyCurr
Posts: 2
Joined: Thu Mar 10, 2011 2:35 pm
Contact:

6VAC Breaker-Point Ignition Coil: Primary & Secondary Resist

Post by EddyCurr » Mon Apr 14, 2014 12:46 pm

This thread is to ask about the role of resistance in the
primary and secondary windings of an ignition coil.

Of particular interest is the 6VAC breaker-point ignition
circuit common to older Japanese motorcycles, where an
A/C generator consisting of a stator and flywheel produces
6VAC output for the primary windings of the ignition coil.

Results from testing resistance for a selection of used coils
and one new coil (for a similar but different model series)
revealed some discrepancies, but not enough is known to
determine whether they are significant or trivial. This testing
also stirred curiosity about the ignition performance consequences
arising from the practice of adding resistance to the secondary
side as a means of inhibiting broadcast signal interference.

** === About the ignition coils ======================= **

A Service Manual gives values of 4-5 kΩ for the secondary
coil winding. No value is offered for the primary winding, but 1 Ω
is presumed.

Three used coils for the model tested at 8 kΩ and 0.7 Ω. Another
tested at 8.54 kΩ and 1.7 Ω. A new 6VAC coil from the same mfr,
but for a different model, tested at 5.4 kΩ and 1.4 Ω

Used Resistance Spark Plug caps tested at 5.81 kΩ. (One example
was fitted with a non-resistance cap that tested 0 Ω.) A new
cap tested at 4.77 kΩ.

** === The questions: ============================== **
  1. All other things equal, what would the consequence of
    increasing resistance on the coil primary side from 0.7 Ω
    to 1.4 Ω and 1.7 Ω be on the intensity of energy across the
    electrodes of a spark plug.
    .
  2. Does an increase from 0.7 Ω to 1.4 Ω and 1.7 Ω on the
    coil primary present a possibility of coil input requirements
    exceeding output of the existing 6VAC generator.
    .
  3. All other things equal, what would the consequence
    of increasing internal resistance on the coil secondary side
    from 4-5 kΩ to 8 kΩ and to 11 kΩ be on the intensity of energy
    across the electrodes of a spark plug.
    .
  4. Is there any difference between increasing secondary
    resistance internally at the windings versus externally
    by way of introducing resistance in the spark plug cap
    and or in the spark plug?
.

EddyCurr
Posts: 2
Joined: Thu Mar 10, 2011 2:35 pm
Contact:

Re: 6VAC Breaker-Point Ignition Coil: Primary & Secondary Re

Post by EddyCurr » Wed Apr 16, 2014 12:09 pm

I see NOW the concluding sentence for the lengthy
description for the Q&A forum: "Submit NEW
questions" to the eMail address mentioned.

May I respectfully suggest that this condition be moved
towards the BEGINNING of that missive. The visually
impaired, the impatient and the functionally illiterate
like myself will appreciate the gesture.

Since posting, I have learned a bit from print resources
that, in part, answers the questions I posed. I think I
can work out more of the answers with a little testing.

No need to respond to the thread.

Post Reply

Who is online

Users browsing this forum: No registered users and 10 guests