Previous Thread
Next Thread
Print Thread
Page 2 of 2 1 2
Re: ballast resistor [Re: moparpro] #2579668
11/17/18 09:24 PM
11/17/18 09:24 PM
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax Offline
top fuel
Mattax  Offline
top fuel

Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Even a stock system usually has left over energy. That's the ringing seen after the spark ends.

Below is a borrowed image so every can see what we're talking about.


You guys who are into this stuff might find this post interesting even though its not the same systems we're discussing. Different coils are being tested to see which one is the overall best for the system and use.
https://bmw.spoolstreet.com/threads/ignition-coil-comparison-primary-energy.1613/

secondary-sparkline.jpg
Last edited by Mattax; 11/17/18 09:35 PM.
Re: ballast resistor [Re: SportF] #2579671
11/17/18 09:39 PM
11/17/18 09:39 PM
Joined: Sep 2007
Posts: 14,889
up yours
Supercuda Offline
About to go away
Supercuda  Offline
About to go away

Joined: Sep 2007
Posts: 14,889
up yours
Originally Posted By SportF
I usually agree with most everything you state Supercuda.

My opinion here, is there is no need to limit anything to the coil, or we'd be building better coils.

These high energy ignitions are high energy because we are putting more in, and getting more out. That's all.

I used to teach electronics, real electronics. Magnetism, transformer action, induction are just some fascinating topics.

Off topic, but part of magnetism, "is aluminum affected by magnetism?" Yes, its repelled. EVERYTHING is affected by magnetism.

And its magnetism that makes a coil work. That concludes todays topics for me.


More specifically, the collapse of the magnetic field is what makes the spark. But the point is if you want a specific output voltage from a transformer you have a couple ways to do it. Overdrive an existing transformer by pumping up the input voltage, like a CD setup, or rewind the transformer to increase
the secondary ratio. One of them increases the voltage in, the other the current. You have to balance the current thru the system and it's cheaper to just use a ballast resistor than it is to use more copper in a coil. We aren't limited to cost considerations and until it became more expensive to not have a high power ignition system the OEM's didn't change what worked, for certain values of work. Emissions got tighter and then things didn't work anymore.

Oh, what causes ringing isn't "left over energy". In electrical circuits, ringing is an unwanted oscillation of a voltage or current. It happens when an electrical pulse causes the parasitic capacitances and inductances in the circuit (i.e. those that are not part of the design, but just by-products of the materials used to construct the circuit) to resonate at their characteristic frequency.

Last edited by Supercuda; 11/17/18 09:41 PM.

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
Re: ballast resistor [Re: Mattax] #2579754
11/18/18 03:07 AM
11/18/18 03:07 AM
Joined: Jan 2003
Posts: 27,421
Balt. Md
3
383man Offline
Too Many Posts
383man  Offline
Too Many Posts
3

Joined: Jan 2003
Posts: 27,421
Balt. Md
Originally Posted By Mattax
Even a stock system usually has left over energy. That's the ringing seen after the spark ends.

Below is a borrowed image so every can see what we're talking about.


You guys who are into this stuff might find this post interesting even though its not the same systems we're discussing. Different coils are being tested to see which one is the overall best for the system and use.
https://bmw.spoolstreet.com/threads/ignition-coil-comparison-primary-energy.1613/



Boy that pic brings back memories from high school when we used the osilliscopes. The points close voltage fluctuations was called the Coil & Condenser oscillactions before electronic ign came out. Of course we were also taught different things to control coil output like the amount of secondary windings and the size and number of the primary windings (primary ohms) which contribute to primary amps along with dwell. Course electronic units can control primary amps and output also by controlling dwell. I like the charts posted in the links and it makes you realize the engineers work hard to build the correct ign systems. When I first got out of high school in 1974 I remember the average coil ohms was about 1 ohm on the primary and about 10,000 on the secondary as it was a general rule of thumb I used on point systems. I can see in the charts on the links how much its has changed with electronic and MSD units. I also remember when Mopar went to coil packs and then the coil secondary windings had to go out the coil wire and to ground to fire two plugs as most coils before had the secondary windings tied to the coil wire and the primary winding when it fired just one plug and not two at one time like the coil packs do. That link is a good read. Thanks for posting it. Ron

Last edited by 383man; 11/18/18 03:09 AM.
Page 2 of 2 1 2






Powered by UBB.threads™ PHP Forum Software 7.7.1