The Ford Barn

rer_239 · 06-26-2019, 04:59 PM

Should both screw terminals on the coil show voltage when ignition switch is on?
Thanks
Dick

Werner · 06-26-2019, 05:14 PM

Dick, one clamp always shows constant current / voltage. The other terminal depends on whether the breaker contact is open or closed.

rer_239 · 06-26-2019, 05:54 PM

Thanks Werner makes sense if I'd stopped to think about it.

Mulletwagon · 06-26-2019, 06:13 PM

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If the system is unmodified, voltage should be present on both coil studs even with the ignition switch off. The ignition switch is wired between the downstream coil stud and the distro which allows the regular grounding through the points to collapse the coil magnetic field and produce the high voltage in the secondary coil winding. A modified system such as electronic ignition, negative ground, 12 volt upgrade is entirely different. On those systems the ignition switch normally supplies voltage to the coil.

06-26-2019, 04:59 PM	#1
rer_239 Senior Member Join Date: May 2010 Location: muskegon, mi Posts: 297	Coil Should both screw terminals on the coil show voltage when ignition switch is on? Thanks Dick

06-26-2019, 05:14 PM	#2
Werner Senior Member Join Date: Jan 2019 Location: Germany, near Aachen Posts: 1,156	Re: Coil Dick, one clamp always shows constant current / voltage. The other terminal depends on whether the breaker contact is open or closed. __________________ Beste Gruesse aus Deutschland, Werner Ford Model A, Roadster, 1928 Citroen 11 CV, 1947 Hercules W 2000, 1976; (with NSU-Wankel Rotary Engine), Canadian version

06-26-2019, 05:54 PM	#3
rer_239 Senior Member Join Date: May 2010 Location: muskegon, mi Posts: 297	Re: Coil Thanks Werner makes sense if I'd stopped to think about it.

06-26-2019, 06:13 PM	#4
Mulletwagon Senior Member Join Date: Jan 2019 Location: Florida Panhandle Posts: 585	Re: Coil Sponsored Links (Register now to hide all advertisements) If the system is unmodified, voltage should be present on both coil studs even with the ignition switch off. The ignition switch is wired between the downstream coil stud and the distro which allows the regular grounding through the points to collapse the coil magnetic field and produce the high voltage in the secondary coil winding. A modified system such as electronic ignition, negative ground, 12 volt upgrade is entirely different. On those systems the ignition switch normally supplies voltage to the coil.