Re: Placement of Ballast Resistor

Posted by Hermit on January 15, 2006 at 17:07:59 from (69.21.48.93):

In Reply to: Placement of Ballast Resistor posted by Thomas Donahy on January 15, 2006 at 07:27:04:

Good discussion. I'll add my two cents worth. The ballast resistor and the coil make up a series resistance circuit duplicating a simple voltage divider circuit. The voltage drop across the coil and the voltage drop across the resistor will be the same no matter where they are in the circuit. So it doesn't matter where the resistor is located. In fact, Chrysler vehicles use to have the resistor between the coil and the distributor. You can adjust the maximum output voltage of the coil by adjusting the value of the resistor. We're talking the change of tenths of ohms. Lower resistance - higher voltage output but more points burning and maybe damage to the coil. Higher resistance - lower voltage output and may cause engine missing. As for secondary current return flow, I believe you may be thinking that battery current flow has something to do with coil induced current flow. They are actually two seperate electrical systems. Where electron flow from the battery causes a magnetic field to develop in the coil, it ends when the points open. The condensor just keeps the points from arcing so much. The moment the points open, the magnetic field collapses, resulting in a large electrical potential (thousands of volts) to develop. The electrical potential is like it's own battery, looking for a place to put all the excess electrons and return to a natural electrical balance. This electron flow goes toward the plugs because of the direction the wire is wound in the coil. At the plug, the electrons jump the gap because of the developed electrical potential. You could see how this electrical potential works if you look at an engine analyzer scope. On a normal running engine, the firing line may be around 5-8 kv since it takes that amount of voltage to jump the gap. However if you completely remove the plug wire, the firing line will go up to the maximum voltage the coil can put out since electrical potential will exist but has no place for the electrons to flow. In fact, that's how you can check the max voltage of the coil. Once the magnetic field collapse is complete, the electrical potential disappears and the cycle starts all over. Hope this helps. It's been fun.

Replies:

Add a Reply Name: E-Mail: Subject: Comments: Optional Link URL: Link Title: Optional Image URL: Email Notification: If you check this box, email will be sent to you whenever someone replies to this message. Your email address must be entered above to receive notification. This notification will be cancelled automatically after 2 weeks.

TRACTOR PARTS	TRACTOR MANUALS

We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]