Jim wrote:
> And finally, to clarify what Tom was saying, it is VERY important that you
> operate the ferrite choke in the range where it is hardly a choke at all, but
> is
> primarily resistive. Why? Simple -- any inductance will increase the current
> by resonating with the capacitance of the short antenna.
>
> I'm currently at an EMC workshop in CA lectured by Henry Ott, so don't
> have time to say a lot more.
>
> Jim Brown K9YC
I appreciate the help everybody is trying to provide me. But frankly, I know
less now than I did before I started this query...
My application is somewhat unique. I have ignition noise eminating from the 8
COPs on my Toyota. This is the same engine (4.7L V8) used in the Lexus, 4
Runner, Tundra, and possibly others. Toyota did not give me much wire to work
with on the engine harness. The connector is about 1" wide with 4 conductors
in-line. They've taken great strides to weather pack the connector to seal out
the elements. There are 4 ~ #18 or #16 wires going to the connector. There is
NO male/female connector available from Toyota, and the connector on the COP is
integrated into the injection molded assembly. I have no options available to
fabricate 8 little EMI suppressors out of available connectors. So I am stuck
attempting to wrap the existing 4 conductors into the bead/toroid or whatever.
A split bead (~ $5 each) of #43 (all I can find available) seems easy enough to
incorporate, but I have doubts about the effectiveness of the #43 material in
this application.
I have enough excess wire on the harness to allow me to slip up to several
toroids over each of the 8 wire assemblies without ripping this $30K vehicle
all apart, effectively voiding the 6 year/70,000 mile warranty. That means one
turn through each core. I would prefer to use a toroid and need to select an
appropriate mix. I will split them by hand and slip them over the wires, using
tape to secure them.
The question remains, what is the best material (among those available) and how
many single turn toroid forms should I plan to incorporate to effectively
suppress this noise? Maybe there is a better way? I'm all ears...
Ford-N0FP
ford@cmgate.com
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