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Going through the Archives on this topic, I came away with the idea that if you want to bring a 1.5 ohm, 240 coil up to the ballast level of 3 ohm of the original coils that came with B18s in PVs and Amazons, you hang a 1.5 ohm resitor between the + and the - terminals on the coil. So, that's what I did, with the result that the resistor turned hot immediately, started smoking and the engine refused to start. Obviously I did something wrong: what? Yes, I know, I should get a Brazilian Bosch blue coil, but I'd still like to know why what I'm trying to do isn't working.
Bob S.
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Obviously, no one told you about people running through cabbage patches.
A resistor is to electricity as a cabbage patch is to people running. If a group of people run through a cabbage patch it offers resistance to their progress.
If you make them run through two cabbage patches in series, they encounter twice as much resistance.
If you allow them to run through two cabbage patches in parallel, there is less resistance because half the people can run through each patch.
The same holds true for current running through resistors.
--
'96 855R,'64 PV544 driver, '67 P1800 basket case, '95 855, '95 854, the first three are mine, heh, heh, 415,000 miles put on 9 bricks
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James;
..."resistor is to electricity as a cabbage patch is to people running"...that's got to be one of the funniest analogies for current flow I've ever heard! I will definately relate that to my friend the physics teacher...I expect he'll get a good chuckle out of it!
...but just how does the analogy explain running between and in line with the rows as opposed to diagonally?
I may have to use that on the SwEm site...what is your source...your high school physics teacher (like the water analogies mine used to use)?...or did it come from your own fertile little brain?
Cheers
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Ron - You are a good judge of sources.
I heard the cabbage patch theory from my high school physics teacher Mr. Connerney. We used to call him the 500 pound canary - he was cool. He drove a couple of old Fiats, but often we would see him walk in during second period after he hitched to school.
Once he told us about the two sailboats off Cape Cod that he owned the salvage rights to. Once, we asked him what his wife thought of his antics, his reply was "Fortunately she doesn't think!"
He never hit it off with the principal and was gone after one year of teaching.
--
'96 855R,'64 PV544 driver, '67 P1800 basket case, '95 855, '95 854, the first three are mine, heh, heh, 415,000 miles put on 9 bricks
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Man, that's got to be rough on the cabages,not to mention the poor babies, but, thanks!
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I know not a lot about the pre-240 Volvos, but about ballast resistors, this might help:
On the early 240s I owned, and on non-Volvo cars in my distant past, ballast resistors served a somewhat odd purpose. They reduced the voltage to the ignition coil primary coil.
That way, when battery voltage is drawn down by the starter's heavy draw, voltage to the coil could be boosted back up by bypassing the ballast resistor. That's what the other spade lug on the starter solenoid was for.
Later 240 models, I think beginning with the Bosch LH type engine management system, the ballast resistor was made unnecessary.
The coil primary winding ground side is closed then opened to create a high voltage in the secondary winding for ignition. Placing the resistor across the coil, during the time the coil was grounded (points closed), made a dead short.
Good Luck,
Bob
:>)
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When you put resistors in parallel you REDUCE the effective resistance,
did you forget already?
And the requirement for the ballast is determined mostly by the coil and
maybe partly by the number of cylinders, so the ballast it had was probably
right.
But where you put it doesn't make any sense at all! Just shorts out the coil.
--
George Downs Bartlesville, Heart of the USA!
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When you put resistors in parallel you REDUCE the effective resistance,
did you forget already?
Well, George, let's put it this way, I can't have forgotten that because I don't remember ever knowing it. You see, I was admitted to college under the condition that I'd never sign up for a Physics class - and that was before anyone had heard of Quantum Mechanics. So, to me, living with something even as elementary as PV makes for an adventurous existence. ;-)
I do remember that on other occasions you mentioned that the resistor should be installed "in series" which, in this simple set-up, would be between the ignition switch and the + on the coil; but I figured that by putting it there I would reduce not only the current for running, but that for starting as well, and that didn't seem like a good idea. So, I figured I'd see what happened if I did it the way I did, since I thought I read something to that effect in the Archives. (I think I got the notion from a post by Joaquín, which I, probably, misread.) The other way would be set up the wiring so that the coil would get its current from the starter solenoid terminal during starting and through the resistor while running, but I figured I'd save that trick for when I got really derperate.
And the requirement for the ballast is determined mostly by the coil and
maybe partly by the number of cylinders, so the ballast it had was probably
right.
The coil is definitely one that would need an external ballast under normal circumstances, but you are right, the way I'm using it, it probably doesn't. At least, during the half hour at a time that I have been running my contraption, the coil hasn't been getting excessively hot.
Bob S.
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No, that's completely wrong; what, exactly, is it that you're trying to do?
BTW, ballast resistors go between + and the coil, not across it.
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