Re: Why the differences in + and - ground electrical systems?

Posted by ltf in nc on May 28, 2000 at 11:00:18 from (206.228.214.242):

In Reply to: Why the differences in + and - ground electrical systems? posted by Alberta Mike on May 27, 2000 at 20:44:51:

1. Why did some manufacturers use + ground and others - ground?
Early on it was only a guess as to the direction of current flow and with the low reving engines it made little difference.
2. Is there any advantage of one over the other?
Yes there is. Proper arrangement gave better performance as the engine rpm and number of cylinders increased
3. Why was the - ground system the one that was eventually used?
As technology improved, the determination was made that currect flow was from newgative to positive
4. Does anyone really know 100% for sure which way the electrons really 'flow'
in a DC electrical circuit, either + to -, or - to +?
I can not prove that the scientists are correct but they state that it flows neg to pos
5. Does anyone use + ground these days on any new applications?
I am uncertain on this. The Brits were slow to change and if anyone does it is probably them.
6. What applications today use 24V electrical systems?
In large heavy duty diesels there are some arrrangements using 24 volts or more. Some of the big engines use air starters also.

I suggest that you use a search engine and research Charles Kettering and his design of the ignition system. There is frequently a lot of debate on the arrangements used in the tractor ignitions. The location of the ballast resistor is one of the major areas discussed. This is a more complicated circuit than the average individual gives credit. Many trained electronic technicians will argue that electronically the arrangements are electrically the same. This is not correct. There are many subtle and often overlooked reasons that Kettering used with his arrangement. When you do the research you will find out that the 12 volts to the primary are actually many times more than this due to what occurs in the collapse of the primary coil voltage and that the secondary voltage actually becomes a very high negative voltage. You will appreciate how the direction of the spark is affected by the heat in the engine and how the current flow in the circuit design is to benefit from the arrangement of the battery polarity.

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