Re: 12 volt front coil

Posted by John T on December 26, 2007 at 16:11:15 from (66.244.83.147):

In Reply to: Re: 12 volt front coil posted by TractormanNC on December 26, 2007 at 15:41:47:

Hi Leonard, Something that could have contributed to the difference is the ohms values of the coil and the ballast resistor you used.

In the IDEAL situation the ballast resistance (around 1.5 ohms) would be near the same as the coils primary (also around 1.5 ohms) such that a true 50/50 voltage divider existed and the coil saw a full 6 volts as designed for. HOWEVER coils varied from maybe 1.25 ohms to under 2 ohms and likewise Ive seen those ballast from 1.5 to 1.85 ohms SOOOOOOOOOOOOOO when you bought an of the shelf ballast it may have been on one end of the spectrum and if the coil was on the opposite end you may have ended up with a voltage divider that only applied 4.5 to 5 volts on the coil i.e low current and a weak spark. HOWEVER that problems not there on that full true 12 volt coil.

Or else maybe (say the voltage divider left sufficient voltage on the coil) the old coil was simply showing its age and that brand new just yielded more spark gap energy as there were less losses to heat or other inefficiencies.

Fun chat, theres other possibilities but I gotta run, will check back later

John T another oldddddddd lol retired EE

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