<VV> Electrical curiosity

Frank DuVal corvairduval at cox.net
Mon Dec 30 13:36:28 EST 2019


But the positive terminal of the coil should never be zero volts. With points closed it is 9 or so. And points open is 12 or more volts. So it varies between 9 and 14 ish running. Then there is the inductive kick of the coil that throws that off and the noise susceptibility of a digital meter and all bets are off to a good reading. 

Frank DuVal

> On Dec 30, 2019, at 8:12 AM, Hugo Miller via VirtualVairs <virtualvairs at corvair.org> wrote:
> 
> To expand on my previous post - the voltage will be bouncing around very rapidly between 9 volts and zero as  the points open and shut. That's going to throw any volt-meter into a state of confusion!
> 
>> On 2019-12-30 13:08, Frank DuVal via VirtualVairs wrote:
>> Was the meter on the coil a DVM?  If so, the leads were picking up
>> the high voltage impulses from the HV side of the coil. Electrical
>> noise.
>> 
>> Frank DuVal
>> 
>>>> On Dec 30, 2019, at 4:00 AM, Smitty via VirtualVairs <virtualvairs at corvair.org> wrote:
>>> 
>>> While working on another issue I came across a situation I can not believe possible.  Car is a 62 with an alternator conversion complete with Late regulator.  In my troubleshooting for the other problem I had two volt meters clipped into the system .  One across the battery terminals and one from ground to the positive terminal of the coil.  This of course was reading through the resistance wire which would normally be showing around 9 volts in the RUN condition.  The battery meter was showing a rock solid 14.2 volts.  The one at the coil though was flashing all over the place showing voltages as high as 19 volts and as low as 8 or 9 volts.  I find it hard to believe that this is normal.  So what gives here?
>>> 
> 



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