Quote:
Originally Posted by twoton
As I’m thinking bout this test and the “You gotta disconnect stuff” , “NO! You don’t gotta disconnect stuff” discussion, it makes me wonder about the proper operation of the condenser as part of the ignition system. I got this book some years ago;
https://www.amazon.com/dp/B002I8H4WE...V170RD6O&psc=0
it has some interesting information in it and with regards to function of the points and condenser;
from page 131… in the split second that the gap resistance starts to create a voltage drop in the battery current, the potential (voltage) stored in the condenser will be greater than the battery voltage across the contacts. This being the case, the condenser instantly begins discharging back through the circuit, in opposition to the battery current. Thus, it effectually heads off and instantly stops the battery current, so that the contacts make a clean break, without any arcing of current across them…..(and on and on blah blah blah).….. we say that the condenser discharge constitutes an oscillatory current of rapidly diminishing value”
So,.. without typing out the entire half page of info about this all (my arm is still really hurting) I would think that if one was to engage in this “test” the second battery source and the function of the points/condenser should be isolated from the starter circuit?
Sorry, just trying to figure this out…  |
That explanation of a condenser’s function is a little simplified and, from my understanding, wrong. Capacitors (condenser in this case) resist changes in voltage, while inductors (the coil) resist changes in current. Putting the two together creates a simple oscillator.
When the camshaft pushes the points open, it breaks the circuit that is completed through the primary windings in the coil. The magnetic field that is created in the core of the coil by the current flowing through the primary windings (when the points are closed) begins to collapse and this collapse induces a very large voltage into the secondary coil windings, which flows from the secondary coil windings through the spark plug electrode and jumps the gap from the electrode to the ground creating the spark. As it collapses, it also induces a relatively large voltage in the primary winding that might jump the gap in the points.
The point of the condenser isn’t necessarily to provide voltage to fire the spark plug, but it’s to stop the current flowing through the primary winding from the collapsing magnetic field from reaching the points and jumping the gap. It’s sort of like an electrical “bumper”. The condenser charges to absorb the current spike from the collapsing magnetic field and then discharges after the current stops flowing partially rebuilding the field in the coil, which then collapses again, but less this time, charging the condenser, which discharges, but less. It’s a simple oscillating circuit that “rings” when you open the points. All this happens while the points are open.
When the points close again, it completes the circuit and the magnetic field rebuilds in the coil starting the whole process over again.
In short, the engine would run fine for a while without a condenser, but the points would be sparking every time the points opened and it would shorten the life of them significantly.