Posted by John T on March 10, 2015 at 12:11:58 from (71.55.236.60):
In Reply to: points diagnosis posted by IanC on March 10, 2015 at 06:16:02:
Here's the deal as I understand it but remember I graduated EE school almost 50 years agooooooooo
When the points are closed and the coil is conducting current there's obviously no current through the shorted out condenser, its a big discharged empty electron bank sittin there. Then when the points open and voltage rises across the points and condenser, the condenser is initially at Time T = 0 +, like a short circuit and conducts current for a short time until its charged up after which it no longer conducts and appears as an open circuit to DC. Then when the points close again that stored condenser energy dissipates and its discharged. If the condenser is sized properly and the LC circuit is correctly sized current is near the same each time so points wear is equal on both sides. If its not the same due to an incorrect condenser value, you get a pit on one side and a hill build up on the other.
The condenser saves the points from premature burning as it accepts current and acts as a shock absorber reducing the burning and arcing across the points. If its open or no condenser at all, she still fires but a weaker spark plus the points burn up too fast. If the condenser is too big she will never fire at all. If its sized correct you get a strong spark plus the points last longer.
Electrons have mass so their bumping into the points sides has an effect and if you figure they are negative charged particles you can figure which way the pit or hill builds up.
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