Farmall Cub Forum -- Questions and answers to all of your Cub related issues.
Tue Feb 17, 2004 9:26 pm
I wouldn't think that the points would wear any faster with the polarity reversed. If the polarity is reversed the contacts would wear just as much but reversed from the original. The current flow determines how and which contact wears (peaks vs pits).
The hole theroy I started investigating when I was about 16. I will be 49 in 8 days and still haven't figured it out.
Tue Feb 17, 2004 10:39 pm
I just love these threads-getting into all this high tech debate. After reconsideration I agree with Bigdoggy. I thought, but can't find it anywhere, that the time constant would change on the cap if you reversed polarity but I haven't anything to support that. Anyway if you buy points and condenser they don't specify polarity. So the long and short of it is the ignition system doesn't care.
Tue Feb 17, 2004 10:44 pm
WKPoor wrote:I just love these threads-getting into all this high tech debate. After reconsideration I agree with Bigdoggy. I thought, but can't find it anywhere, that the time constant would change on the cap if you reversed polarity but I haven't anything to support that. Anyway if you buy points and condenser they don't specify polarity. So the long and short of it is the ignition system doesn't care.
That would make one wonder why the polarity is marked on the coil? To me it seems coil polarity would determine polarity for the points and condenser.
Tue Feb 17, 2004 10:58 pm
The polarity is marked because both the primary and secondary windings are attached to the + terminal. Only the primary windings are attached to the - terminal. The coil will work either way but if connected improperly may cause damage over a long period of time. Also it may take much more voltage to create a spark. Resulting in a power loss.
I have a very good textbook that I can scan and send to Rudi explaining the ignition system. This may help clear up a few topics that have been brought up lately.
Tue Feb 17, 2004 11:26 pm
Bigdog wrote: I've heard theories on "hole" flow vs. "electron" flow (although it's been a few years and I probably don't remember much) and it gets a lot of arguments started between engineers and technical people.
Hole flow, versus electron flow theory, is just a theory. What actually makes elctronics work is smoke. Anytime the smoke leaks out, the electronic circuit quits working. If you can seal the smoke in, it will run forever!
Wed Feb 18, 2004 12:05 am
I was under the impression that the hole vs. electron flow only had relevance inside semiconductors. Otherwise it doesn't matter.
We have gone around on the behavior of coils and if positive and negative ground coils are different. I'm not convinced I have heard a satisfactory exlanation yet. Not going to take the time to dig into my reference material now either.
Whichever way a system is grounded, the condenser is what keeps the points from burning. To do that, the capacitance has to be the right value. If it is too low, the points burn from spark jumping one direction. Too high, they burn the other way. The correct value has to be effected by virtually any change to the system. Reversing the ground and coil connections has to make a difference. I would expect ballast resistors and anything else in the circuit to make a difference too. If you believe the engineers did a erasonable job of selecting the condenser in the first place, any change has to be detrimental to ignition point life.
By the way, all 6-volt Cubs were originally positive ground, including the '62 models.
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