Ford 9N ignition question.

Years ago my neighbor and I bought a 9N tractor together. we used the tractor for many years and then for various reasons we parked it for
several years. Deciding to use it again I wasn't able to get any spark, even though it worked fine when we parked it. After cleaning the points I was able to confirm that the points were properly adjusted and making contact. Opening and closing the points by hand resulted in an erratic and weak spark. Tracing the really simple electrics I found that the power from the battery goes through a ballast resistor. Unlike cars and other vehicles with ballast resistors that I'm familiar with the ballast resistor is bypassed during starting. But the old Ford 9N tractor doesn't do this. I ended up connecting the coil directly to the battery and this resulted in a pretty good spark. Good enough that the tractor started right up. So why the ballast resistor? Why would the current need to be limited for regular operation if the ballast resistor isn't bypassed during starting? Anyway, I am not going to run the tractor with the ballast resistor out of the circuit because It is supposed to be there. And before it was parked for several years it worked just fine. I think the reason for the poor spark must be corroded connections somewhere in the ignition circuit. But I'm still wondering why they designed the ignition circuit with a ballast resistor. Anybody know? Thanks, Eric
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 04/24/2017 3:35 PM, snipped-for-privacy@whidbey.com wrote: ...

--



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks for the link. It explains it perfectly. Eric
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

http://www.myfordtractors.com/index.shtml
http://www.learnabout-electronics.org/ac_theory/dc_ccts45.php The resistor AND a coil designed to generate the spark with a lower input voltage decreases the time for the magnetic field to build up when the points close, without overheating the coil from its internal resistive loss.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 24 Apr 2017 18:06:07 -0400, "Jim Wilkins"

It also slows the burn-up rate of the contact points. I remember very well when a tuneup lasted only 6,000 miles. I made a living from it. ;)
Hey IGGY, got any of those tractor manuals on your site?
--
Well, the trouble with our liberal friends is not that they

--Ronald Reagan
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Monday, April 24, 2017 at 4:34:08 PM UTC-4, snipped-for-privacy@whidbey.com But I'm s till wondering why they designed the

The total resistance is the wiring, the ballast resister , and the resistan ce of the coil primary. If all the resistance was zero, the current would initially be controlled by the inductance of the coil, but would be high an d burn the points. Some coil essentially have a built in ballast resistor and do not need or use an external ballast resistor.
When you are starting the engine the voltage is lower. So if you short out the ballast resistor it is closer to how it is when the engine is running. So even with the lower voltage when starting , you get a good spark.
Dan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 24 Apr 2017 16:40:39 -0700 (PDT), " snipped-for-privacy@krl.org"

I know about the shorting Dan, read my post that you replied to a little more carefully. I wanted to know why the ballast is there when it is never bypassed. dbp sent me a link and now I understand. Eric
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Monday, April 24, 2017 at 4:34:08 PM UTC-4, snipped-for-privacy@whidbey.com wrote: I think

Forgot to say that the weak spark might be caused by a bad condenser. THe condenser helps keep the spark from occurring across the points instead of at the spark plug.
Dan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@krl.org wrote:

I've got no familiarity with what a condenser is (outside of HVAC) in car circuitry. But thanks for saying what it does.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 25 Apr 2017 15:19:17 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

It is actually a Capacitor. A rose by any other name - - -
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tuesday, April 25, 2017 at 7:25:21 PM UTC-4, Clare wrote:

Right. "Condenser" is the old name for it. It disappeared in radio decades before automotive types abandoned the term.
--
Ed Huntress

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tuesday, April 25, 2017 at 7:25:21 PM UTC-4, Clare wrote:

Its just that a condenser also refers to the hot, liquid, high pressure 'low side" of a vehicle's air conditioning system. Its not always a good idea to have two different auto parts with the same name.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thursday, April 27, 2017 at 6:40:35 PM UTC-4, snipped-for-privacy@gmail.com wrote:

They've got to do something about "wheel," then. <g>
I haven't heard "condenser" for "capacitor" for a long time. I'll have to look at my really old engine books to see when it last showed up.
--
Ed Huntress

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 27 Apr 2017 16:10:06 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

Then there's two different fenders, and two different hoods, dpending where you are in the world.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

https://electronics.stackexchange.com/questions/222137/why-was-a-capacitor-called-a-condensor-condenser-in-the-early-days-of-electro "Not that anyone cares, but "condenser" seems to have faded from use from the mid 1930s through about 1950. Dubilier was using capacitor by 1940 but Allied catalogs didn't switch to capacitor until around 1950."
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 27 Apr 2017 22:51:23 -0400, "Jim Wilkins"

NAPA / Echlin was still using Condenser in 1998 (their catalog U138)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 27 Apr 2017 23:00:38 -0400, snipped-for-privacy@snyder.on.ca wrote:

I know the condenser is a capacitor. But when you say "I replaced the points and capacitor" people look at you strange. So when I am doing a tune up on a points ignition vehicle I replace the condenser. When anything else I say capacitor. Eric
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thursday, April 27, 2017 at 10:51:29 PM UTC-4, Jim Wilkins wrote:

It hung on later in reference to car ignotion, though. I remember seeing it in some tune-up manuals from the early '60s.
I really don't want to go into that corner of the attic but maybe I'll get to it. <g>
--
Ed Hunress

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Condensor is the old Latin name for them.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 4/27/2017 11:01 PM, snipped-for-privacy@gmail.com wrote:

My '78 Fiat manual used "condenser"
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.