"ballasted" coils

I've read references to "ballasted" coils ( as opposed to, I assume, "non-ballasted" coils ). Is the word "ballast" being used in this context essentially the same thing as "resistor" -----------does anyone out there know for sure ?

There can be internal ballast, external ballast and non ballasted coils. I would have to see it context to understand what they are getting at.
Ballast is something that stabilizes something else, like a ballast in a ship, keeps the ship on an even keel. In electricity it refers so something that stabilizes the circuit like a ballast in a florescent lamp fixture.
In the Ign circuit a ballast resistor is used to limit the inrush current when the points close. This allows the coil to charge faster to max flux than if an unballasted coil is used.
As a general rule, four or six cyl engines on 6 volts turning less than 3200-3400 rpm (for 4 stroke) used un ballasted coils. V-8's and engines that turned faster used ballasted coils on 6 volt. Most all 12volt (and higher) use some form of ballasted coil regardless of number of cyl in the engine or how fast it turns.
Coil on plug and coil packs (that fire only 2 cyl) generally don't need ballasts.
Whether to ballast or not is a function of how fast the coil has to cycle (how many times it has to fire in a period of time) and how high the supply voltage is

I can't remember the last time I saw a ballasted coil on "new" stuff. There are lots of COPs that have the coil driver integral with it. There's usually a heat sink visible on these.
I always thought the ballast was to protect the points from burning if the dist. happened to stop in the closed position.
CB, some old vehicles use a "ballast wire" instead of the ceramic ballast. Why is that?

Wire vs. ceramic resistor was a mfg choice, the wire made it hard to find and change. I remember the wire on Ford mostly but I think IHC may have also used it at some point.
If you look at the Ford Flathead V8's and the Lincoln and LaSale V12 and V16, all were 6 volt and used a ballast, where as the 4 and 6 cyl of the day did not. It has to do with how fast the coil had to cycle. With a Ballast you can lower the impedance (effective resistance) and still limit the in rush current which tend to "buck" the magnetic flux. All coils resist a change in current the same way all capacitors resist the change in voltage. By limiting the inrush, the coil charges and a steady rate, and by lowering the impedance, the total charge is greater.
With slow turning 4 and 6 cyl this isn't a big deal, but double the rate of firing and it becomes one.
The Condenser has more to do with points not burning, but also preforms another function. Ign system theory is a whole class by itself, and it is hard to sum up each components job in a short reply.

I had the ignition class! At least twice. In college. I think that impedance and coil flux, etc. were judged to be too heady for dumbass mechanics. For example, the famous movie they show you (from the 1950s) uses BASEBALL to try to educate you about ignition systems.
We were taught to match things up on a stock ignition system. Buy and use the correct parts.
I'll look for that old movie.

http://imperialclub.com/Repair/Electrical/coil.htm


This is typical of what I've been taught in numerous classes. JC, ROP, and correspondence classes. They can't ALL be wrong, CB.
I think the ballast has SOMETHING to do with point protection. As does the condenser.
Your explanation of engine speed vs. ballast or not ballast is the rest of the puzzle.

My info come straight from the FAA Powerplant manual. It is a common repeated statement about "burning the points" but that doesn't hold up to theory. If reducing the current was for points, why then on six volt (which uses twice the current for the same work) do we not see ballasts in every case? Same for "bypassing it for starting" why then wouldn't you see it on six volts? Many places, rather than get into coil theory and deep into everything, it is just simpler to say it needed for whatever reason. In practice it is not important for most to know why, but to know that it is needed
Mag's also don't use a ballast, and the reason is the Mag generates it's own current and the amount in the primary builds as the magnet approaches the E gap setting, so it is self limiting This is true even tho a mag at speed can see much higher primary voltage than a battery and coil. Mag's aren't prone to burning points, because the primary current rises and falls as the magnet rotates into and out of the coil pole shoes.
All coils resist changes in current flow, be it a armature or field coils in a motor, or a coil on a bobbin of a relay or an ign coil. Break the circuit and you get an arc, It is not the inrush current that tends to burn points but the arcing when the circuit is opened. One of the purposes of the condenser (capacitor) is to quash the arc when the points open. The other is to store and release the induced voltage in the primary generated when the magnetic flux collapse thru the primary as well as the secondary. This gives the familiar "sawtooth" pattern seen on an ign scope. It is not one spark, but multiple sparks as the flux collapses thru both coils in the ign coil.
Likely more than you ever wanted to know!

CB, here we go again with the FAA!
Are we FLYING these old things?
The "FAA" guys that show up here know more than I ever will except they don't work on what I do. It's COMICAL.
Left RUDDER, CB! Right RUDDER, CB!
I've had any number of very knowledgeable and experienced instructors repeat "the WRONG IDEA". This includes TEXTBOOKS. You know, textbooks?
If I had to accept YOUR version or the other DOZENS I'll have to accept the others.
NO offense, of course!
Keep 'em flying, CB!

CB, here we go again with the FAA!
Are we FLYING these old things?
The "FAA" guys that show up here know more than I ever will except they don't work on what I do. It's COMICAL.
Left RUDDER, CB! Right RUDDER, CB!
I've had any number of very knowledgeable and experienced instructors repeat "the WRONG IDEA". This includes TEXTBOOKS. You know, textbooks?
If I had to accept YOUR version or the other DOZENS I'll have to accept the others.
NO offense, of course!
Keep 'em flying, CB!

No offence taken, and in reality, unless you are designing your own ign system from scratch it makes little difference why, only that you do need one.
A lot of things became clear getting my A&P lic (Aircraft mechanics Lic).
What you deal with day in, day out would leave most A&P's scratching their head (or running for the hills).
Back when I was in A&P school we still had to know radial engines back to front, like which way the cam ring turns on a specific model engine! Why you would need to know that off the top of your head, I never could figure out. This was in the time that most of my class who ended up working in the field ('Nam vets) worked on turbine engines, of which there were very few questions on the test.
I'll say this, the FAA put out some **** good textbooks, and I still have mine and refer to them every once and a while. Beats GM's school on OBD and TBI all to hell, TBI being almost an exact update of a "pressure carb" that aircraft used in the 50's.

Clear right! Clear left!
Clear out!